Department of Nephrology Hopital Pitie-Salpetriere 83, boulevard de l'Hopital 75013 Paris France
vincent.launay-vacher@psl.aphp.fr
Dr Vincent Launay-Vacher is Clinical Pharmacist in the Department of Nephrology at Pitie-Salpetriere Hospital in Paris, France. Since 1999, he is in charge of ICAR, a national medical advisory service on drug management in patients with renal failure (renal tolerance, dosage adjustment, …) dedicated to French physicians. Dr Launay-Vacher is the author of a number of publications mainly in international journals, on drug pharmacokinetics and renal effects. His clinical research activities have focused on the study of drugs’ pharmacokinetics and dosage adjutsment in patients with renal insufficiency. He coordinated a National study called “IRMA” (Renal Insufficiency and Anticancer Medications)on the prevalence of renal insufficiency in French cancer patients. This study included near 5000 patients and demonstrated the high prevalence of impaired renal function in cancer patients and the consequences on anticancer drugs handling regarding their potential toxicity and their dosages in such patients. The results of “IRMA” have been presented at the 2005 ECCO and 2006 ASCO meetings, and has been published in 2007 in “Cancer”, the Journal of the American Cancer Society. Dr Launay-Vacher is member of the French Society of Nephrology, the International Society of Geriatric Oncology (SIOG), the European Society of Clinical Pharmacy (ESCP), and is Vice-President of the European Fellowship for Pharmacists (EFP). He is member of the Education and Training Committee of ESCP and on the board of the ESCP Special Interest Group on Cancer Care. He also collaborates on the Task Force on Renal Insufficiency and Safety in the Elderly Cancer Patient of the SIOG and on the Task Force in the Elderly of the EORTC.
In December 2010, the website dedicated to the Adjustment of drug dosage in patients with renal insufficiency has been launched : SiteGPR (http://www.sitegpr.com).
Abstract: BACKGROUND: Glomerular filtration rate (GFR) decline with age increases the risk of inappropriate dosing of drugs. We investigated the determinants and the mortality associated with the use of drugs that are contraindicated or require dose adjustment according to kidney function among the community-dwelling elderly. METHODS: The Three-City population-based study included 8701 participants â¥65 years from 1999 to 2001. Exposure to the risk of inappropriate drug dosage was defined as reported use of either a contraindicated drug or one requiring dose adjustment according to the individual baseline glomerular filtration rate estimated (eGFR) with the Modification of Diet in Renal disease study equation. Six-year mortality was analysed using Cox models adjusted for several sociodemographic, biologic and clinical risk factors. RESULTS: The overall percentage of exposure to the risk of inappropriate drug use was 13.3% (contraindication, 0.8%): it was 52.5% (4.5%) in those with an eGFR of 30-59 and 96% (48%) in those <30mL/min/1.73 m(2). Antihypertensive agents, fibrates and psycholeptics accounted for most of the drugs with dosing recommendations and antidiabetic agents and antihistamines for those contraindicated. Individuals at risk were more likely to be men, older, and under treatment for hypertension or hypercholesterolemia. Exposure to either risk was independently related to higher all-cause mortality (hazard ratio 1.4, 95% confidence interval 1.0-1.9) in participants with eGFR <60 mL/min/1.73 m(2). CONCLUSIONS: Contraindicated drug prescription was uncommon but >10% of the population took drugs requiring renal dosing adjustments. Regular monitoring of eGFR may prevent excess mortality associated with inappropriate drug prescription in the elderly.
Abstract: Drug-induced renal dysfunction is frequent in clinical practice. Outcomes may be severe, with increased morbidity and mortality. Kidneys are particularly vulnerable to drug toxicity, especially since they are highly vascularized, thus receiving about 25% of cardiac output. Furthermore, interstitial accumulation of toxic agents in papilla and the medulla often occurs due to the existence of a corticomedullary osmotic gradient. Moreover, the key role played by the renal tubule in the reabsorption processes of a number of endogenous and exogenous substances further increases the exposure of the kidney to high concentrations of potentially toxic agents, both in the tubular lumen and cells. As a result, drugs may be toxic to all of the four structures of the kidney: glomerulus, tubule, interstitium, and blood vessels. This chapter reviews the main mechanisms of drug-induced renal toxicity and then focuses on the nephrotoxicity of anti-infectious drugs: antibacterial drugs, antifungal agents, antimalariae, and antiviral drugs. NSAID and anticancer drugs renal toxicity are detailed elsewhere in this textbook. Methods used to prevent drug-induced nephrotoxicity, when known, are detailed. Risk factors are also listed, such as high-risk populations, identification and elimination of risk factors, and drug dosage adjustment in patients with baseline abnormal renal function.
Abstract: The Renal Insufficiency and Anticancer Medications (IRMA) study is a French national, observational study which demonstrated the high prevalence of abnormal renal function in a population of 4,684 solid tumour patients. Among them, 50-60% had decreased renal function defined as CrCl below 90 and 80% were treated with anticancer drugs that either necessitated dosage adjustment in case of RI or were potentially nephrotoxic drugs. Since patients and drugs used differ depending on the type of tumour, the IRMA Study Group started analyses in different subgroups of patients. In the 1898 IRMA patients with breast cancer, the prevalence of RI was still very high in spite of a normal serum creatinine in almost all cases. Some anticancer drugs, as in particular some bisphosphonates, capecitabine and platinum salts, may be nephrotoxic and/or need dosage adjustment. However other important drugs in breast cancer do not require dose reduction, and do not present with potential nephrotoxicity (anthracyclines, taxanes, trastuzumab). Both issues seem to be slightly but significantly more important in patients with bone metastases as compared to patients with a non-metastatic disease.
Abstract: Kidney disease has been shown to be highly prevalent in cancer patients in the IRMA studies (Renal Insufficiency and Anticancer Medications). Furthermore, anticancer drugs used in those patients, among which half have abnormal renal function, necessitate dosage adjustment in case of reduced renal function and/or is potentially toxic to the kidneys in the vast majority of cases. Observations performed in IRMA-2 showed that the survival rate at 2 years was significantly lower for patients with KD (aMDRD<60). This reduced survival has been hypothesized to be related to the cardiovascular complications of KD or as a consequence of inappropriate drug dosage adjustment.
Abstract: half of anticancer drugs are predominantly excreted in urine. Dosage adjustment in renal insufficiency (RI) is, therefore, a crucial issue. Moreover, patients with abnormal renal function are at high risk for drug-induced nephrotoxicity. The Belgian Renal Insufficiency and Anticancer Medications (BIRMA) study investigated the prevalence of RI in cancer patients, and the profile/dosing of anticancer drugs prescribed.
Abstract: PURPOSE: Side effects of antiangiogenic agents are moderate compared with other therapies. The most frequent adverse events are of a renovascular origin and manifest as hypertension (HTN) and thrombotic microangiopathy. To date, data are scanty on the renal tolerance of such drugs regarding renal function as itself, i.e., glomerular filtration rate (GFR). We report on the evolution of GFR in patients receiving antiangiogenic therapy after unilateral nephrectomy for kidney cancer. PATIENTS AND METHODS: Data from 73 patients followed in our oncology department for kidney cancer, who had undergone unilateral nephrectomy, and received any antiangiogenic therapy were reviewed. Their GFR was calculated using the aMDRD formula. RESULTS: All patients showed a declining renal function over time (-1.23 and -2.51 mL/min/1.73 m(2) using the slope of the curve or the difference between GFR at baseline and that at the end of treatment, respectively). Among them, patients who were recorded as having HTN before initiation of antiangiogenic therapy showed a higher decrease in their GFR of -13.28 and -12.06 mL/min/1.73 m(2). CONCLUSION: We recommend that blood pressure should be measured closely in those patients before initiation of antiangiogenic therapy. When HTN is diagnosed, it should be treated and renal function should be monitored since those patients may be at risk for rapidly decreasing renal function under therapy.
Abstract: Antiangiogenic therapy has now become a cornerstone in the treatment of several solid tumor cancers. Those drugs present with a renal toxicity profile manifesting as proteinuria and hypertension, often reported in the literature to be linked to bevacizumab, a monoclonal antibody targeted at the circulating vascular endothelial growth factor (VEGF). However, there is evidence that those side effects are most probably related to the pharmacological action of those drugs: the inhibition of the VEGF pathway. Thus, they may occur with any antiangiogenic therapy, either those acting on circulating VEGF (bevacizumab or VEGF-trap), or those acting on VEGF receptor(s) (sunitinib, sorafenib, or axitinib). Clinicians should thus be aware of such a 'class effect' to appropriately monitor and treat their patients, regardless of which antiangiogenic drug is used.
Abstract: The prevalence of renal insufficiency before and at 1, 12, and 60 months after liver transplantation (LTx; primary endpoint) and the changes in the glomerular filtration rate (GFR) at same time points according to the immunosuppressive regimen (coprimary endpoint) were investigated. The primary outcome was determined for the entire cohort, whereas the coprimary endpoint was determined only for 2 groups of patients: those who started and remained on a calcineurin inhibitor (CNI) alone, that is, the CNI-alone group (n = 624), and those who started and remained on a CNI in combination with mycophenolate mofetil (MMF), that is, the MMF group (n = 117). GFR was <60 mL/minute/1.73 kg/m(2) in 11%, 48%, 51% and 58% of the patients at baseline and at 1, 12, and 60 months, respectively. The decrease in GFR was significantly lower in the MMF group compared to the CNI-alone group at 12 and 60 months (-16% versus -30% and -15% versus -33%, respectively), whereas the GFR decrease at 1 month was not different between the 2 groups. There were no significant differences between the 2 groups in CNI doses or blood levels at 12 and 60 months. In conclusion, there was a worsening of renal failure in 83% of patients post-LTx; 58% and 5% had GFRs of <60 and <30 mL/minute/1.73 kg/m(2), respectively, at 5 years after LTx. The reduction of the GFR was significantly less marked in the MMF group compared to the CNI-alone group, and this could be related to less important CNI exposure early after LTx. It seems likely that early intervention for CNI reduction is best for reducing the use of CNIs in the long term.
Abstract: Contrast medium (CM)-induced nephropathy (CIN), defined as acute renal failure after administration of CM when alternative causes of renal damage have been excluded, is the third leading cause of acute renal injury necessitating hospitalization. However, the pathophysiology of CIN is complex and not fully understood. Gadolinium chelates, originally introduced as intravenous CM for magnetic resonance imaging and regarded as nonnephrotoxic, have been recommended to replace iodinated contrast agents in patients at risk for acute renal failure. Since then, some gadolinium-based CM have been reported to be associated with CIN, especially in patients with advanced renal disease. However, the biochemical and physicochemical properties of the gadolinium-chelates that are responsible for such nephrotoxicity have not been clearly defined, and the issue of gadolinium-induced nephrotoxicity remains controversial. This review surveys the literature with the purpose of clarifying the renal effects of gadolinium-based CM in patients with renal insufficiency.
Abstract: The Renal Insufficiency and Anticancer Medications (IRMA) study is a French national, observational study which demonstrated the high prevalence of abnormal renal function in a population of 4684 solid tumor patients. Among them, 50-60% had decreased renal function, and 80% were treated with anticancer drugs that either necessitated dosage adjustment in case of renal insufficiency (RI) or were potentially nephrotoxic drugs. Since elderly patients are well-known to have reduced renal function, either due to physiological aging or their disease/medication history, a subgroup analysis of this particular population of patients was performed. In 1553 IRMA patients whose age was > or =65 years, the prevalence of RI was very high in spite of normal serum creatinine values in most cases. Anticancer drugs used may be nephrotoxic or need dosage adjustment in a high number of cases.
Abstract: The Renal Insufficiency and Anticancer Medications (IRMA) study reported the high prevalence of renal insufficiency in cancer patients. In this special report, we focused on patients with lung cancer, emphasizing some specific findings in this population of patients. Data on patients with lung cancer who were in the IRMA study were analyzed. Renal function was calculated using Cockcroft-Gault and abbreviated Modification of Diet in Renal Disease (aMDRD) formulas to estimate the prevalence of renal insufficiency (RI) according to the KDOQI-KDIGO definition. Anticancer drugs were studied with regard to their potential renal toxicity and need for dosage adjustment. Of the 445 IRMA lung cancer patients, 14.4% had a serum creatinine (SCR) level > or =110 micromol/L. However, when they were assessed using the formulas, 62.1 and 55.9% had abnormal renal function. Of the 644 anticancer drug prescriptions, 67.5% required dose adjustments for RI or were drugs with no available data, and 78.3% of the patients received at least one such drug. Furthermore, 71.6% received potentially nephrotoxic drugs. Seventy percent of the patients had anemia but prevalence was not significantly associated with the existence of associated renal insufficiency. In the 445 IRMA patients with lung cancer, the prevalence of RI was high in spite of a normal SCR in most cases. Some anticancer drugs such as platinum salts may be nephrotoxic and need dosage adjustment. However, other important drugs such as gemcitabine do not require dose reduction and do not present with a high potential for nephrotoxicity. Lung cancer patients often present with anemia, which was not associated with the presence of RI.
Abstract: Dermatological effects are among the most frequent side-effects in patients receiving erlotinib (Tarceva). However, there no official recommendations on the preventive or curative management of those erlotinib-related skin effects (ERSE). The "Prise En Charge des Effets Dermatologiques sous Erlotinib" (PRECEDE) study was designed to study how ERSE are being managed in France.
Abstract: The Renal Insufficiency and Anticancer Medications (IRMA) study reported a renal insufficiency (RI) prevalence of 50%-60% in a population of almost 5000 patients with solid tumors, 80% of whom were being treated with anticancer drugs that either necessitated dosage adjustment or were potentially nephrotoxic drugs. A national multicenter study from 15 cancer centers in France analyzed IRMA data on patients with prostate cancer.
Abstract: Antineoplastic drugs used in the treatment of cancers present with variable renal tolerance profiles. Among drugs with a potential for renal toxicity, platinum salts, methotrexate, and gemcitabine are well-known. The mechanisms of their renal toxicity and the means of its prevention are presented in this article. Anti-angiogenic drugs, recently marketed or still under clinical development, may also interact with the kidneys. In general, optimising the renal tolerance of anticancer drugs requires an appropriate evaluation of patients'renal function, before and during treatment, at each course. Serum creatinine alone is not a reliable index of renal function. Its evaluation must be performed with the use of Cockcroft-Gault or aMDRD formulae. In patients with abnormal renal function, dosage adjustment is often required to improve the renal tolerance, and also to limit the risk of extra-renal toxicities (such as haematological toxicities) induced by a drug overdosage, in those patients with reduced drug-elimination.
Abstract: Antineoplastic drugs used in the treatment of cancers present with variable renal tolerance profiles. Among drugs with a potential for renal toxicity, platinum salts, and especially cisplatin is a well-known agent that may induce acute and chronic renal failure. The mechanisms of its renal toxicity and the means of its prevention are presented in this article which represent the Clinical Recommendation from the Special Interest Group on Cancer Care of the European Society of Clinical Pharmacy (ESCP).
Abstract: The prevalence of kidney disease (KD) indicators together with the profile of RA drugs prescribed in RA patients was investigated in the MATRIX study (MeThotreXate And Renal Insufficiency).
Abstract: BACKGROUND: The Renal Insufficiency and Cancer Medications (IRMA) study is a French national observational study. The results from this study of nearly 5,000 patients demonstrated the high prevalence of renal impairment in a population of patients with solid tumors. METHODS: Every cancer patient who presented at oncology departments that participated in the study over at least 1 of 2 predefined periods during 2004 were included. Renal function was calculated using Cockcroft-Gault and abbreviated Modification of Diet in Renal Disease (aMDRD) formulae to estimate the prevalence of renal insufficiency (RI) according to the Kidney Disease Outcomes Quality Initiative-Kidney Disease Improving Global Outcomes definition and stratification. Anticancer drugs were studied with regard to their potential renal toxicity and dosage adjustment. RESULTS: Of the 4,684 patients from the 15 centers, 7.2% had serum creatinine levels >110 micromol/L. However, when they were assessed using Cockcroft-Gault and aMDRD formulae, 57.4% and 52.9% of patients had abnormal renal function or RI, respectively. Of the 7,181 anticancer drug prescriptions, 53.4% required dose adjustments for RI. Of the patients treated, 79.9% received at least 1 such drug. And 80.1% received potentially nephrotoxic drugs. CONCLUSIONS: RI was common in patients with cancer, and drug dosage adjustments often were necessary. Renal function should be evaluated in all cancer patients using either the Cockcroft-Gault formula or the aMDRD formula, including patients with normal serum creatinine levels. In patients who are at high risk for drug toxicity, the dosage should be adapted to renal function, and the use of nephrotoxic therapies should be avoided whenever possible.
Abstract: BACKGROUND: Elderly cancer patients commonly have renal function decline. This warrants particular caution during the administration of renally excreted cancer drugs or those with established nephrotoxicity. DESIGN: An International Society for Geriatric Oncology task force was formed to discuss treatment recommendations for this group of patients. RESULTS: Before drug therapy, the assessment and optimization of hydration status and evaluation of renal function is required. Serum creatinine alone is insufficient as a means of evaluating renal function, and creatinine clearance should at least be calculated in every patient by the abbreviated modification of diet in renal disease or Cockcroft-Gault equations. In the extremes of obesity and cachexia and at very high and low creatinine values, no single tool is really accurate. In these patients, the best estimate of glomerular filtration rate is provided by direct methods such as (51)Cr-EDTA or inulin measurement. Within each drug class, preference may be given to agents less likely to be influenced by renal clearance, which are minimally nephrotoxic, or for which appropriate methods of prevention for renal toxicity exist. Coadministration of known nephrotoxic drugs should be avoided or minimized. CONCLUSIONS: Future trials should be designed to present data in a way that allows evaluation of the contribution of renal function to toxicity and efficacy.
Abstract: BACKGROUND: Several studies have revealed the frequency of antiretroviral (ARV) drug prescription errors. We analyzed highly active antiretroviral therapy (HAART) prescribing practices for human immunodeficiency virus (HIV)-infected patients undergoing hemodialysis in France. METHODS: Prescribed ARV drug doses in our cohort (consisting of all HIV-infected patients who underwent hemodialysis from 1 January 2002 and were prospectively followed up until 1 January 2004) were compared with the recommended doses for patients undergoing hemodialysis. The log-rank test was used to compare the outcomes among different groups of treated patients. RESULTS: One hundred seven of the 129 patients in our cohort received a total of 317 ARV drugs, 59% of which were improperly prescribed. The dosing was too low for 18% of the patients and too high for 39% of the patients. Twenty-eight patients (26%) did not receive any of their ARV drugs at the recommended dose. The lowest prescribed dose (8% of the daily recommended dose) was observed with indinavir and zidovudine, and the highest prescribed dose (1000% of the recommended dose) was observed with stavudine. Among patients who received HAART, those who were prescribed an insufficient dose of a protease inhibitor had more-severe HIV disease and worse 2-year survival than did the other patients (mean rate of survival+/-standard deviation, 79.5%+/-7.5% vs. 95.4%+/-2.6%, respectively; P<.02). For dialyzable ARV drugs, the delay between ARV drug receipt by the patients and dialysis sessions was not respected in 9% of cases, and in 73% of cases, it was not known whether the patients took the ARV drugs before or after dialysis sessions. CONCLUSION: This is, to our knowledge, the first study to show a significant association between ARV drug prescription errors and survival in patients undergoing dialysis.
Abstract: Amprenavir is an HIV-1 protease inhibitor which is hepatically metabolized (>80%) with a low renal elimination. It has thus been suggested that no dosage adjustment is necessary in patients with renal dysfunction. However, no data are available on the pharmacokinetics of amprenavir in patients with renal insufficiency. We report on the pharmacokinetics of amprenavir in two HIV patients with severe and end-stage renal insufficiency. Amprenavir pharmacokinetics did not differ in our patients as compared with normal renal function subjects. Furthermore, amprenavir was not dialysable (FHD<25%). As a result, the drug may be administered at its normal dose in patients with renal failure, even when severe. In dialysis patients, amprenavir may be administered before or after the session.
Abstract: A SIOG taskforce was formed to discuss best clinical practice for elderly cancer patients with renal insufficiency. This manuscript outlines recommended dosing adjustments for cancer drugs in this population according to renal function. Dosing adjustments have been made for drugs in current use which have recommendations in renal insufficiency and the elderly, focusing on drugs which are renally eliminated or are known to be nephrotoxic. Recommendations are based on pharmacokinetic and/or pharmacodynamic data where available. The taskforce recommend that before initiating therapy, some form of geriatric assessment should be conducted that includes evaluation of comorbidities and polypharmacy, hydration status and renal function (using available formulae). Within each drug class, it is sensible to use agents which are less likely to be influenced by renal clearance. Pharmacokinetic and pharmacodynamic data of anticancer agents in the elderly are needed in order to maximise efficacy whilst avoiding unacceptable toxicity.
Abstract: Drug-induced kidney injury is a major side effect in clinical practice. Renal injury associated with drugs may involve several components of the kidney: glomerulus, tubules, interstitium, and blood vessels. Acute renal failure may occur as a major reaction to many drugs. Moreover, therapeutic agents may induce an allergic reaction leading to interstitial inflammation and tubular damage. In this article, we present an updated version of the bibliography containing the case reports of nephrotoxicity published in the international literature from January 2003 to December 2005.
Abstract: BACKGROUND: Chronic kidney disease (CKD) is extremely common in adults, although often undiagnosed and thus untreated. Cardiovascular disease is the leading cause of death among patients with CKD and reducing its risk in this population is an important priority. Dyslipidemia is almost always present when proteinuria is above 3 gr/24 hours. Roughly two thirds of all patients with end-stage renal failure and kidney transplants suffer from dyslipidemia and should receive lipid-lowering therapy, as suggested by recent Afssaps (French drug agency) and NKF-K/DOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) guidelines. We reviewed recent studies on efficacy, tolerability and prescription recommendations of statins in CKD and renal transplant patients. METHODS: We searched Medline, the international medical database, to conduct a systematic review of the literature on the efficacy and tolerability of statins in CKD and renal transplant patients and on specific recommendations for dosage adjustments in this population. RESULTS: The efficacy of statins in decreasing total cholesterol and LDL-cholesterol levels in dialysis and renal transplant patients is similar to that in the general population. On the other hand, large-scale randomized clinical trials among CKD (4D) and renal transplant (ALERT) patients do not demonstrate that statins significantly decrease rates of cardiovascular disease. They have a beneficial effect on proteinuria and lower the rate of kidney function deterioration in patients with dyslipidemia. Early introduction of a statin in transplant patients did not lead to improved kidney function or prevent loss of the graft. Although most statins are not excreted by the kidneys, the dosage of some must be adapted in CKD patients because of pharmacokinetic modifications induced by renal impairment. CONCLUSION: Statins at appropriately adapted doses have the same efficacy in CKD patients as in subjects with normal kidney function, and tolerance is not a problem. Their effectiveness in cardiovascular prevention in this population has not been demonstrated to date. Results about statin-induced kidney protection are encouraging but further and more specific studies are needed.
Abstract: Normal renal function depends upon an intact glomerular apparatus. Many drugs and chemicals are capable of damaging the glomerulus, causing its increased permeability to large molecules. Glomerular lesions are usually responsible for proteinuria and the nephrotic syndrome. This also holds true for the drug-induced glomerulopathies, of which membranous glomerulo-nephritis is the most frequent type of lesion encountered. Apart from this, several cases of different glomerular changes such as focal segmental glomerulosclerosis and crescentic glomerulonephritis have also been reported. The drug-induced glomerulopathies are probably immune mediated. This is, for instance, reflected in the fact that patients with drug-induced nephritic syndrome frequently have the HLA-B8 and DR3 antigens. In depth information is provided for the previously mentioned disorders.
Abstract: Blood pressure (BP) varies according to cycles characterized by a reduction during sleep and an increase on awakening. The nighttime decrease is absent or blunted in some patients (termed "non-dippers"). Cross-sectional and prospective data have shown that non-dippers have more target organ damage than have dippers in normotensive and hypertensive subjects. We reviewed the English language literature regarding this association. A non-fortuitous association seems to exist between non-dipper status and cardiovascular risk such as stroke and cardiac events. Among diabetic patients, this phenomenon has been described to occur more often in individuals with autonomic neuropathy and with different degrees of diabetic nephropathy. In normoalbuminuric normotensive type I diabetic patients without any degree of autonomic dysfunction, according to traditional cardiovascular tests, diastolic BP (dBP) night/day ratio is associated with an increased glomerular filtration rate and an increased extracellular volume. The disruption of the circadian rhythm of sympathovagal activity in non-dipper patients was associated with higher levels in systolic BP (sBP) and dBP and with a reduced decline in sBP and dBP levels during the night. Therefore, the prognostic implications of the non-dipper status may be important since the overall 24-h blood pressure load is elevated in these individuals. These data suggest that patients in whom blood pressure decreases during the night incur less damage to their brain, kidneys, heart, and blood vessels than people with elevated nocturnal BP.
Abstract: The kidney plays an important role in the elimination of numerous hydrophilic xenobiotics, including drugs, toxins, and endogenous compounds. It has developed high-capacity transport systems to prevent urinary loss of filtered nutrients, as well as electrolytes, and simultaneously to facilitate tubular secretion of a wide range of organic ions. Transport systems for organic anions and cations are primarily involved in the secretion of drugs in renal tubules. The identification and characterization of organic anion and cation transporters have been progressing at the molecular level. To date, many members of the organic anion transporter, organic cation transporter, and organic anion-transporting polypeptide families have been found to mediate the transport of diverse organic ions. It has also been suggested that ATP-dependent primary active transporters such as MDR1/P-glycoprotein and the multidrug resistance-associated protein family function as efflux pumps of renal tubular cells for more hydrophobic molecules and anionic conjugates. Tubular reabsorption of peptide-like drugs such as beta-lactam antibiotics across the brush-border membranes appears to be mediated by two distinct H+/peptide cotransporters: PEPT1 and PEPT2. Renal disposition of drugs occurs through interaction with these diverse secretory and absorptive transporters in renal tubules. Studies of the functional characteristics, such as substrate specificity and transport mechanisms, and of the localization of drug transporters could provide information regarding the cellular network involved in renal handling of drugs. Detailed information concerning molecular and cellular aspects of drug transporters expressed in the kidney has facilitated studies of the mechanisms underlying renal disposition as well as transporter-mediated drug interactions.
Abstract: BACKGROUND: Tenofovir disoproxil fumarate (TDF) was developed for the treatment of human immunodeficiency virus (HIV) infection. However, controlled data are sparse on the long-term renal tolerability of TDF at the currently approved daily dose of 300 mg in treatment-naive HIV-infected patients. METHODS: Over 144 weeks, this 600 patient, multicentre randomized, placebo-controlled, double-blind trial compared stavudine (301 patients) and TDF (299 patients), both administered in combination with lamivudine and efavirenz, in antiretroviral-naive patients. TDF or placebo and stavudine or placebo were administered in an open-label fashion. All medications were taken orally. At screening, all patients had serum creatinines <1.5 mg/dl, calculated creatinine clearances > or =60 ml/min and a serum phosphorus > or =2.2 mg/dl. RESULTS: The incidences of grades 1 (> or =0.5 mg/dl increase from baseline), 2 (2.1-3.0 mg/dl) and 3 (3.1-6.0 mg/dl) serum creatinine elevations at week 144 were 4, <1 and 0%, respectively, in the TDF group and 2, 0 and <1% in the stavudine control group (P = NS). There were no grade 4 (>6 mg/dl) serum creatinine elevations. At week 144, there was no change from baseline in the mean (0.83 mg/dl) serum creatinine in the TDF group compared with a 0.1 mg/dl decrease from baseline (0.83 mg/dl) in the stavudine control group. The incidences of grades 1 (2.0-2.2 mg/dl), 2 (1.5-1.9 mg/dl) and 3 (1.0-1.4 mg/dl) hypophosphataemia at week 144 were 4, 3 and <1%, respectively, in the TDF group and 4, 2 and <1% in the control group (P = NS). No patient experienced grade 4 (<1.0 mg/dl) hypophosphataemia. At week 144, the decrease (Delta) of mean serum phosphorus levels from baseline in both groups was similar (Delta 0.2 from 3.6 mg/dl for the TDF group, and 0.1 from 3.5 mg/dl for the stavudine control group). No patient developed Fanconi's syndrome or proximal renal tubular dysfunction during the study. CONCLUSION: Through 144 weeks, TDF and stavudine, each administered in combination with efavirenz and lamivudine, had similar renal safety profiles in treatment-naive HIV-infected patients with normal renal function at baseline.
Abstract: Tuberculosis is re-emerging in patients with altered immune status, such as those with chronic renal failure. Clinicians should thus be aware of the pharmacokinetics and dosage adjustment of antitubercular drugs in patients with renal insufficiency. Among patients with renal insufficiency, those who are dialysed should be treated with special care. Indeed, dosage should always be closely adjusted in these patients and potential removal by dialysis must be taken into account. However reliable the dosage adjustment recommendations are for these drugs in patients with renal failure, further pharmacokinetic investigations need to be performed, especially in dialysis patients in whom the influence of haemodialysis and continuous ambulatory peritoneal dialysis on drug pharmacokinetics needs to be detailed. In the meantime, it could be generally advised to administer all antitubercular drugs after the haemodialysis session, even though some drugs are known to be non-dialysable.
Abstract: Methotrexate (MTX) has become the most commonly prescribed disease-modifying anti-rheumatic drug. However, toxicity is an important drawback of MTX therapy and permanent discontinuation of MTX for adverse effects occurs in 1 patient out of 10. Although high-dose MTX is known to be nephrotoxic, data on low-dose MTX renal effects are scanty. We report an insidious and progressive deterioration of renal function during long-term low-dose MTX in a 59-year-old woman. Kidney biopsy revealed advanced kidney fibrosis with extensive interstitial and glomerular fibrosis, and vascular sclerosis. We suggest that patients on low-dose MTX therapy even alone, should be periodically monitored for creatinine levels.
Abstract: PPAR-gamma ligands, including thiazolidinediones, have recently become clinically available for treating insulin-resistant diabetes mellitus. Accumulating evidence suggests that these drugs not only significantly improve insulin sensitivity but also may have antiproteinuric effects in genetically obese diabetic rodents and patients with type II diabetes and diabetic nephropathy. Moreover, troglitazone reduced expression of ECM proteins and transforming growth factor-beta in glomeruli from streptozotocin-induced diabetic rats. Many other properties including antiproteinuric, hemodynamic, and antihypertensive effects in insulin-dependent diabetes mellitus suggest that PPAR-gamma ligands might have a direct, beneficial renal effect, independent of their capacity to improve glucose tolerance. Besides their antidiabetic effects, thiazolidinediones have been shown to lower blood pressure in diabetic patients with hypertension and patients with diabetic nephropathy through multiple mechanisms. Several studies showed the efficacy of PPAR-gamma agonists to ameliorate the progression of glomerulosclerosis. The effect is independent of insulin effects and could only be partially due to lipid effects. These renal protective effects of PPAR-gamma agonists suggest that they may provide a novel intervention strategy to prevent vascular and glomerular sclerosis.
Abstract: AIMS: To review the medications that influence glucose metabolism with a focus on hypertensive, transplant and HIV-infected patient populations. METHODS: Literature obtained from a MEDLINE search from 1970 to present, including studies published in the English language. The search strategy linked drugs, hyperglycaemia and diabetes mellitus, HIV, transplantation, hypertension and psychiatric patients. RESULTS: Many common therapeutic agents influence glucose metabolism. Multiple mechanisms of action on glucose metabolism exist through pancreatic, hepatic and peripheral effects. The prevalence of hyperglycaemia was higher with the use of thiazide diuretic, beta-blocker, calcineurin, protease inhibitors and atypical antipsychotic drugs. CONCLUSIONS: Patients treated with those drugs appear to be at increased risk for developing diabetes. It is prudent to monitor plasma glucose values when it is not possible to avoid prescription of medication with known effects on carbohydrate metabolism.
Abstract: Drug-induced kidney injury is a major side effect in clinical practice. Renal injury associated with drugs may involve several components of the kidney: glomerulus, tubules, interstitium and blood vessels. Acute renal failure may occur as a major reaction to many drugs. Moreover, therapeutic agents may induce an allergic reaction leading to interstitial inflammation and tubular damage. In this article, we present an updated version of the bibliography containing the case reports of nephrotoxicity published in the international literature from January 2003 to December 2004.
Abstract: Nephrotoxicity is an inherent adverse effect of certain anticancer drugs. Anti neoplasic drugs have a narrow therapeutic index and the amount of drug necessary to produce a significant reduction in tumour burden usually produces significant nephrotoxicity. The dosage used in clinical trials represents often the maximum tolerated doses determined during phase I drug evaluation. Greater toxicity is acceptable during curative therapy than during palliative therapy. But cancer patients often exhibit excretory reduced organ function. Modulation of pharmacokinetics and pharmacodynamics of these drugs in cancer patients is therefore necessary in order to improve tolerance. Patients with malignancies are particularly vulnerable to development of renal abnormalities. Conversely, patients with renal abnormalities who have undergone kidney transplantation are at high risk for malignancy. Clinical syndromes of renal involvement are diverse and sometimes insidious. Despite the recent advances in understanding the mechanism of anticancer drug nephrotoxicity, prevention still relies on drug dosage decrease and active screening for renal abnormalities as part of the usual biological work up in patients treated with anticancer drugs.
Abstract: Adverse drug reactions in the elderly are of growing concern because of the increasing elderly population and the increasing numbers of medications prescribed to this group. Ageing and the frequent comorbid diseases in the elderly result in altered drug pharmacokinetics and pharmacodynamics increasing the risk of side effects. The decline in renal function affects the elimination of many drugs. Before prescribing an estimation of the glomerular filtration rate is of the highest importance. All the nomogramms and formulae are approximate in the oldest old. The Cockcroft and Gault formula is frequently used. Pharmacodynamic alterations are particularly important for the centrally active drugs that older people are more vulnerable to, for example increased and prolonged effects of anticholinergic, hypnotic and sedative drugs. Polypharmacy and self-medication is also common in these patients, with increased chance for drug-drug interactions. In France, the recent law on Public Health (August 09, 2004) requires for the next five years to decrease the frequency of inappropiate prescriptions in elderly people and of to decrease the frequency of the drug-induced hospitalisations. Undertreatment of the elderly is not the solution: it's necessary to optimize their medication: to well appreciate before prescription their motor and cognitive deficiencies interfering with compliance, to "start low and go slow" their medications, to review their drug consumption on a regular basis, to educate them and their family for a good observance.
Abstract: A FREQUENT AND EXPENSIVE PROBLEM: Ninety percent of contrast media nephrotoxicity (CMN) occur in patients with pre-existing kidney failure. Its aggravation may require early chronic dialysis. PREVENTIVE MEASURES: CMN prophylaxis is important in these patients. Pre- and post-hydration, with infusion of isotonic saline solution or sodium bicarbonate, and reduction of contrast medium (CM) volume to the strict minimum are essential for preventing CM-induced kidney failure. THE INTEREST OF PROPHYLACTIC HEMODIALYSIS AND HEMOFILTRATION: An interesting approach in preventing CMN is the early elimination of the CM with dialysis techniques. Preventive hemodialysis does not reduce the risk of CMN, but hemofiltration has shown significant efficacy in a population of patients with kidney failure. THE INTEREST OF IMMEDIATE HEMODIALYSIS IN CHRONIC HEMODIALYSIS PATIENTS: Although nephrotoxicity is no longer a problem in patients undergoing chronic hemodialysis, CM, especially in high-dose injections, may be responsible for fluid and electrolyte abnormalities and/or volemic expansion. No data yet justify a conclusion that a hemodialysis session immediately after injection of a CM in chronic dialysis patients might be helpful.
Abstract: Drug-induced kidney injury is a major side effect in clinical practice, frequently leading to acute renal failure (ARF). It accounts for more than 2% to 15% of cases of ARF in patients admitted to the hospital or in the intensive care unit, respectively. The exact frequency of nephrotoxicity induced by antiviral drugs is difficult to determine. Antiviral drugs cause renal failure through a variety of mechanisms. Direct renal tubular toxicity has been described with a number of new medications with unique effects on epithelial cells of the kidney. These include cidofovir, adefovir dipivoxil, and tenofovir, as well as acyclovir. Additionally, crystal deposition in the kidney may promote the development of renal failure. Several different drugs have been described to induce crystal nephropathy, including acyclovir and the protease inhibitor indinavir. Renal injury associated with antiviral drugs involves diverse processes having effects on the renal transporters, as well as on tubule cells. In this article, we review the pathogenesis of antiviral drug-induced kidney injury, common nephrotoxic renal syndromes, and strategies for preventing kidney injury.
Abstract: Dyslipidemia is frequent in patients with renal failure and in transplant recipient patients. This lead to a wide use of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) in patients with impaired renal function or in patients treated with cyclosporine as post-transplantation immunosuppressive therapy. As a result, it is crucial for those patients' physicians to be aware of how to handle these drugs when renal function is impaired and/or when cyclosporine is co-administered. Most statins have an extensive hepatic elimination and the renal route is usually a minor elimination pathway. However, pharmacokinetic alterations have been described for some of these drugs in patients with renal insufficiency. Cyclosporine is a widely used immunosuppresive therapy in solid organ transplant patients and drug-drug interactions are likely to occur when statins and cyclosporine are administered together. Those interactions may theoretically result in increased statins and/or cyclosporine serum levels with potential muscle and/or renal toxicity. As a result, caution is warranted if concurrent administration is performed. In this review, we synthesized the data from the literature on (1) the pharmacokinetics and dosage adjustment of atorvastatin, fluvastatin, pravastatin, rosuvastatin, and simvastatin in patients with renal failure and (2) the potential drug-drug interactions between these drugs and cyclosporine in transplant recipient patients.
Abstract: The World Health Organization established official recommendations for managing pain in cancer patients. Since then, this stepladder approach has been widely adopted as a conceptual framework to treat all types of pain. However, those guidelines have not been critically evaluated for use in patients with renal insufficiency. In these patients, the questions of drug dosage adjustment and renal toxicity must be considered. This article reviews the pharmacokinetics of major analgesic drugs and data on their use and/or behavior in renal failure and considers their potential nephrotoxicity. Finally, according to available data in the international literature on pharmacokinetics, recommendations for dosage adjustment in patients with renal failure, and their potential nephrotoxicity, the World Health Organization three-step ladder for the treatment of pain was modified and adapted for patients with impaired renal function. Perspective This well-known treatment strategy now adapted for use in patients with renal insufficiency should secure and rationalize pain treatment in those patients.
Abstract: We report a case of biopsy-proven acute interstitial nephritis (AIN) in a 50-year-old diabetic woman, who had been treated with celecoxib for 4 weeks before presentation. She presented with clinical findings of renal proximal tubulopathy, aseptic leukocyturia and acute renal failure. A kidney biopsy specimen showed AIN with intense tubuli and eosinophilic infiltrate in the interstitium. She recovered normal renal function two weeks after cessation of celecoxib and use of a corticosteroid. A review of the literature yielded eight cases of COX-2 inhibitor-associated AIN with a biopsy-proven diagnosis. Among the reported cases, AIN was diagnosed after an average of 8.3 months of therapy (SD 12 months, range 3 days - 3 years) with 25 mg rofecoxib or 200 mg celecoxib daily. Common symptoms included asthenia, anorexia, nausea and vomiting. The classic triad of fever, rash and eosinophilia was uncommon. Typical laboratory features included hematuria, proteinuria, eosinophilia. Renal failure was common at the time of diagnosis. Mean serum creatinine levels were 0.86 +/- 0.11 mg/dl, 5.66 +/- 3.50 mg/dl and 1.15 +/- 0.24 before treatment, at time of diagnosis and 1 - 2 months after COX-2 inhibitor withdrawal, respectively. Three patients required emergency hemodialysis. After cessation of COX-2 inhibitor treatment, patients recovered completely with a normalized serum creatinine level after one to two months. Management consisted of withdrawal of the COX-2 inhibitor drug and in four patients, corticosteroid therapy was well-tolerated and may have been beneficial.
Abstract: BACKGROUND: In hemodialyzed patients, physicians have to (1) adjust drug dosage for a creatinine clearance lower than 10-15 ml/min and (2) know whether or not the drug will be removed by the dialysis session to decide whether it may be administered before or after the session on dialysis days. However, of several indices being used to evaluate drug removal by dialysis none is appropriate and we suggest a novel index named F(HD), which reflects the role of hemodialysis clearance of a drug in its overall clearance during the session. METHODS: Pharmacokinetic simulations were performed to test the influence of dialysis on the pharmacokinetics of some drugs, whether F(HD) was considered or not, to determine when to administer the drug. F(HD) was then calculated for several drugs and its value compared with other indices. Five hemodialysis patients from our department for whom the time of drug administration was determined according to F(HD) were included in a small study and their drugs' trough concentrations were monitored. RESULTS: F(HD) emphasized that considering hemodialysis clearance alone may lead to false interpretations of the potential dialyzability of some drugs. In our patients, who received their treatment according to the 'F(HD) rule', monitoring of trough levels gave satisfactory results. CONCLUSION: The use of the 'F(HD) rule' should be tested on a long-term administration basis to confirm our conclusion. F(HD )could be the index of choice to determine when to administer a drug, before or after the session, in hemodialysis patients.
Abstract: PPARgamma nuclear receptors are mainly expressed in adipose tissue. However, they are also expressed in renal glomerular tissue and in vascular walls, thus participating through various and complex mechanisms, to glomerular and vascular sclerosis and to nephropathy development and progression. Studies carried out with glitazones, pharmacological agonists of nuclear receptor PPARgamma, in experimental models, either in vitro, or in vivo in animal models, have demonstrated their favourable effects on arterial blood pressure and on prevention and/or progression of diabetic nephropathy. The few clinical studies conducted in type 2 diabetic patients to assess these effects, are also in favor of a beneficial effect of glitazones on blood pressure and nephropathy in these patients. Thus, it appears extremely important and fully justified to conduct specific studies in patients with type 2 diabetes, with the aim to establish and to better characterize these effects in various clinical conditions (antihypertensive effect in treated hypertensive patients according to the class of antihypertensive agents used, prevention of diabetic nephropathy and/or effect on its progression, renal protection, etc.). Some adverse events, although with a low incidence, may be associated with glitazone use (weight gain, peripheral oedema, fluid retention, etc.), and may limit their use in some patients. It is clearly important to better understand the pathophysiological mechanisms of these effects and their possible long term consequences. Finally, it is important to emphasize the easiness to use glitazones in patients with renal insufficiency, without the need to adjust the drug regimen.
Abstract: Systemic disposition of antiviral drugs partly depends on renal handling of these compounds. There are some known, functionally characterized anionic and cationic transporters with varying substrate specificities for those drugs: human organic anion transporter (OAT) family (hOAT1-3) and human organic cation transporter (OCT) family (hOCT1-3), which mediate the intracellular flux, and adenosine 5'-triphosphate (ATP) binding cassette transporter family (P-glycoprotein, MRP2-5), which mediate the cellular efflux of antiviral drugs. The peptide transporter (PEPT1-2) mediate bi-directional facilitated diffusion of valacyclovir. All these transporters are expressed in the kidney. Organic anion and cation transporters primarily localize to the basolateral membrane of renal epithelial cells while ATP-binding cassette transporters primarily localize to the apical membrane. These transporters work in concert to mediate renal intracellular concentration of occurring antiviral drugs. Along with drug-metabolizing enzymes, these transporters are important determinants of drug effectiveness and toxicity. This review examines the role that these transporters play in renal disposition of antiviral drugs.
Abstract: The safety of tenovir disoproxil fumarate (TDF) was assessed in two double-blind, placebo-controlled studies. Furthermore, we retrospectively collected 19 cases of TDF-associated tubular dysfunction. The incidence of renal events was similar among the active TDF groups and the placebo group in the two double-blind, placebo-controlled studies. Proximal tubulopathy was diagnosed 6.89 +/- 5.51 months after TDF therapy started. All abnormalities normalized within 4.7 +/- 2.94 weeks after drug discontinuation.
Abstract: BACKGROUND: Chronic renal failure is a common pathology. The high frequency of this disease in the general US population has been assessed in the NHANES III study. However, the frequency of chronic renal insufficiency among cancer patients remains unclear. MATERIAL/METHODS: 316 cancer patients were in a one-month study, included regardless of their pathology, treatment (antineoplastic drugs used or programmed to be used, pretreated, or no treatment), or any other criteria. RESULTS: Among the patients, 287 (90.8%) had normal serum creatinine levels (<110 micromol/l), i.e. a frequency of 9.2% for renal insufficiency in our population. However, when renal function was estimated by calculating creatinine clearance using the Cockcroft and Gault formula, 33% of the patients had an estimated GFR of less than 80 ml/min. Among these, 28% had a creatinine clearance ranging form 80 to 50 ml/min and 5% had a creatinine clearance of less than 50 ml/min. Renal insufficiency is frequent in cancer patients since almost one third of the patients present renal insufficiency. Furthermore, among patients with normal serum creatinine levels, one patient out of five has asymptomatic renal insufficiency. CONCLUSIONS: Therefore, it is of major importance that renal function be assessed by calculation of creatinine clearance using the Cockcroft and Gault formula in every patient, even when serum creatinine is within the normal range.
Abstract: With the introduction of highly active antiretroviral therapy (HAART), human immunodeficiency virus (HIV) infection has become a chronic disease with more frequent end-stage organ failures. As a result, the question of transplantation in HIV patients is raised more often. However, some of the HAART regimen medications require elimination or metabolism via the P-glycoprotein (P-gp) and multidrug-resistant protein (MRP) transporters or via the cytochrome P450 enzyme system. Since these transporters and enzymes are also responsible for the clearance of immunosuppressive drugs, drug-drug interactions are likely to occur. Indeed, profound drug-drug interactions between protease inhibitors and immunosuppressive drugs have been observed and they required reductions in drug dosage. In contrast, HAART using nucleoside or nonnucleoside reverse transcriptase inhibitors without the use of protease inhibitors has been shown to produce less significant drug-drug interactions. It is thus crucial to take into account those potential pharmacokinetic and/or pharmacodynamic drug-drug interactions in order to avoid drug toxicity or a lack of efficacy. The aim of this work was to review and synthesize the international literature on this field in order to give practical recommendations on how to manage immunosuppressive drugs in HIV patients who get transplanted and on how to handle HAART therapy in transplant-recipient patients who get infected with HIV.
Abstract: BACKGROUND: The incidence of adefovir dipivoxil (ADV) nephrotoxicity has been previously reported with the 60 and 120 mg daily dose in human immunodeficiency virus (HIV). We report a complete analysis on the renal tolerance of ADV at the currently approved dose of 10 mg daily for the treatment of chronic hepatitis B. METHODS: To investigate the efficacy, safety, and the tolerability of two dosing regimens of ADV (10 mg daily or 30 mg daily), two double-blind, placebo-controlled studies were performed in patients with chronic hepatitis B and compensated liver disease who were not undergoing current treatment and who had evidence of hepatitis B virus (HBV) replication. RESULTS: There was no overall median change from baseline at week 48 in serum creatinine or serum phosphorus levels in the ADV 10 mg group. In the ADV 30 mg group there was a slight increase of 0.2 mg/dL in median serum creatinine levels, and decrease of 0.1 mg/dL in serum phosphorus levels at week 48. Serum creatinine increase and hypophosphatemia were more frequently observed in patients receiving ADV 30 mg daily compared with ADV 10 mg and placebo. There were no grade 4 proteinuria, hematuria, or glycosuria events. CONCLUSION: Mild nephrotoxicity was demonstrated with the dose of 30 mg daily. Nephrotoxicity, as defined by an increase >/=0.5 mg/dL from baseline in serum creatinine or a serum phosphorus value of <1.5 mg/dL on two consecutive occasions, was not observed in patients treated with ADV 10 mg for a median follow-up period of approximately 64 weeks.
Abstract: The association between ear and kidney anomalies is not usually due to an insult to the embryo. In recent years, many essential development control genes that coordinate the assembly and function of kidney and ear have been discovered through the generation of animal mutants and have increased our understanding of the mechanisms of human oto-renal diseases. Here, we describe ear and kidney clinical syndromes and their molecular expression.
Abstract: BACKGROUND: Acquired immunodeficiency syndrome (AIDS)-related kidney disorders concern 30% of those patients and can lead to end-stage renal disease (ESRD; 0.6 to 1%). Therefore, administration of antiretroviral drugs in human immunodeficiency virus (HIV) patients with nephropathy is not uncommon. AIM OF THE REVIEW: Since renal insufficiency is not uncommon among HIV-infected patients treated with antiretroviral drugs, guidelines on how to use these drugs in the pattern of an altered renal function are mandatory. This review provides such guidelines established on the basis of pharmacokinetic and clinical studies reported in the international literature. In addition, some of these drugs may be nephrotoxic. Mechanisms and clinical and/or biological manifestations are reviewed to help monitor renal tolerance in patients receiving these drugs. CONCLUSION: Antiretroviral drugs' dosage in HIV-infected patients with altered renal function should be cautiously determined. Drug dosage should not be systematically reduced since dosage adjustment is not mandatory for all therapies (ie. protease inhibitors). Furthermore, when dose reduction is necessary, pharmacokinetic and clinical data from the literature allows to establish practical guidelines on how to use these drugs in such patients.
Abstract: Peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the large nuclear receptor superfamily. Its main role is to activate genes involved in fatty acid oxidation in the liver, heart, kidney and skeletal muscle. While they are mainly used as hypolipidemic agents, PPARalpha agonists may also be postulated to exhibit renoprotective effects. This review summarizes current knowledge regarding the effects of PPARalpha agonists on the kidney.
Abstract: Vasculitides form a heterogeneous group of diseases characterized by blood-vessel inflammation and necrosis. They have a wide spectrum of manifestations because of the involvement of arteries and other vessels of various sizes and locations. Early diagnosis and prompt treatment may decrease the morbidity and mortality associated with these disorders. Examination of the eye and kidney should be performed routinely in those diseases. This article reviews the major types of oculorenal manifestations in systemic autoimmune diseases.
Abstract: World Health Organization statistics identify 150 million people with diabetes mellitus worldwide and suggest that this figure may double by 2025. In countries with a western lifestyle, the number of patients admitted for renal replacement therapy with diabetes as a co-morbid condition has increased significantly up to three to four times in a period of 10 years. Diabetes and renal failure are thus tightly linked diseases, and so is anemia. However, whether anemia may be worsened and/or directly, at least in part, caused by diabetes is not clearly elucidated yet. In this article, we review the prevalence, pathophysiology and consequences of anemia in diabetic patients.
Abstract: Fanconi's syndrome (FS) was first described by Lignac in 1924. Associated with numerous varieties of inherited and acquired conditions, FS is characterized by a generalized transport defect in the proximal tubules, leading to renal losses of glucose, phosphate, calcium, uric acid, amino acids, bicarbonates, and other organic compounds. Cardinal symptoms of the syndrome are hyperaminoaciduria, glucosuria in the face of a normal serum glucose level, and phosphate wasting. Other symptoms may be associated, such as defects in bicarbonate reabsorption; renal acidification; urate reabsorption; urinary concentration; potassium conservation; reabsorption of sodium, calcium, and low-molecular-weight proteins; and secretion of p-aminohippuric acid. Acquired renal tubular defects resulting in FS also have been described in association with many exogenous agents, whether administered or accidentally ingested. This review concentrates on drug-induced FS.
Abstract: OBJECTIVES: The potential consequences of medication misuse in renal impairment have not been assessed in a population of in-patients. The purpose of this study was to determine the frequency and potential consequences of a lack of dosage adjustment in hospitalized patients with renal impairment. DESIGN: Order sheets for in-patients having a creatinine above 0.7 mg/dl were analysed. We considered the appropriateness of prescriptions for medications having potential nephrotoxicity and/or eliminated through renal excretion or metabolism (TEM medications) and having manufacturer's guidelines for dosage adjustment in renal impairment. MAIN MEASURES: On the basis of these guidelines, each line of prescription was rated as 'appropriate order', 'inappropriate dosage', or 'contra-indicated order'. Experts also rated prescriptions as potentially fatal or severe, serious, significant, or without potential for increased adverse effects. RESULTS: Two hundred and two order sheets were completed for 164 patients. They totalled 1469 lines of prescription, 85% of which were TEM medications, with guidelines for dosage adjustment for 71% of them (n = 886). Of these 886 prescriptions, 34% were inappropriate, 14% being contra-indicated and 20% with inappropriate dosage given the patient's renal function. Among the 202 order sheets, 75% included at least one inappropriate prescription. Sixty-three per cent included at least one prescription with potentially adverse consequences, 3% of these having potentially fatal or severe consequences. CONCLUSION: This study confirms that physicians do not take into account sufficiently patient renal function when prescribing. In light of these results, improving the quality of drug prescription in patients with renal impairment could be of importance for improving the quality of care.
Abstract: OBJECTIVE: Although fitting orders to renal function avoids overdosage and therefore iatrogenic risk, dosage adjustment is rarely made. The objective of this study was to assess residents' prescribing behavior in renal impairment, through a standardized simulated clinical setting. METHOD: This criterion-referenced study was carried out in a French teaching hospital. The hospital had 118 residents; 71 of them were asked to complete a questionnaire including four vignettes, simulating drug prescription in four 'patients' with various degrees of renal impairment (16 orders). The patients had an order of gentamicin sulfate, diclofenac sodium, and amlodipine bensylate. For each drug, the resident could maintain the order, discontinue the order, or change the dosage. A fourth drug, enalapril maleate, was to be started, with three possible dosages and the possibility of not prescribing it. The reference chosen for assessment was the Vidal dictionary, which corresponds to the Physician's Desk Reference and is the French reference for prescription. RESULTS: All the residents approached for the survey accepted the offer to complete the questionnaire. Among the 16 simulated orders, the median number of appropriate orders per resident was nine. Considering the renal function of their patients, 62% of residents wrote an inappropriate order for gentamicin, 42% wrote an inappropriate order for didofenac, and 52% wrote an inappropriate order for enalapril. Although no adjustment to renal function was required, 28% of the residents decreased the dosage of amlodipine and ordered an underdose. CONCLUSION: Considering the iatrogenic risk related to the lack of dosage adjustment, attention should be drawn to increasing residents' awareness of dosage adjustment in renal impairment and to providing them with better information on patients' renal function.
Abstract: HIV patients are at a high risk for nephrotoxicity (HIV-induced nephrotoxicity, HIVAN). As a result, renal insufficiency, tubular dysfunction and renal-related biological disorders are frequently observed in those patients. However, in some cases those defects or anomalies in renal function may be related to antiviral therapies rather than the disease itself. This article reviews the incidence, presentation, prevention and management of antiviral drug-induced renal dysfunction.
Abstract: The prevalence of HIV-positive subjects in dialysis (hemodialysis and peritoneal dialysis) population varies from 0.13 to 0.36% in italian and french studies, respectively. Most drugs used in HIV therapy are primarily excreted by the kidney. In patients with renal insufficiency, careful dosage adjustment is mandatory to optimize drug exposure and reduce the risk for adverse events. We review the impact of peritoneal dialysis on the pharmacokinetics of antiviral drugs, and discuss on the dosage recommendations needed to achieve efficacy and avoid toxicity in patients with end-stage renal disease undergoing continuous ambulatory peritoneal dialysis (CAPD).
Abstract: Seventeen cases of severe hyponatremia induced by angiotensin-converting enzyme (ACE) inhibitor therapy have been reported in the literature. The mechanism of severe hyponatremia induced by ACE inhibitor is not clear. A 60-year-old white man with a history of idiopathic dilated cardiomyopathy was treated with enalapril, 20 mg daily, that had been started 2 weeks before heart transplantation. The serum sodium level was 138 mmol/L before initiation of enalapril therapy and 127 mmol/L just before cardiac surgery. In the post-heart transplantation period, enalapril therapy was withdrawn for the perianesthesia period, and the serum sodium level increased from 127 to 140 mmol/L. One month later, viral myocarditis developed in the patient and enalapril was reintroduced at 20 mg daily. Two weeks later, natremia decreased. Enalapril was discontinued. Three days later the serum sodium level rose to 140 mmol/L. Severe symptomatic hyponatremia induced by the syndrome of inappropriate secretion of antidiuretic hormone should be considered a rare but possible complication associated with ACE inhibitor therapy.
Abstract: BACKGROUND: Significant lymphopenia is a prominent feature in systemic erythematous lupus, but has not been described in Wegener's granulomatosis (WG). We suggest from a retrospective analysis that lymphopenia may also be an index of WG disease activity. METHODS: Medical charts form 19 patients diagnosed with systemic active WG between 1990 and 2000 were reviewed retrospectively. All patients had crescentic glomerulonephritis and alveolar hemorrhage. Clinical and biological markers were reviewed at three different time points: diagnosis, time of relapse, and during remission. RESULTS: Average lymphocyte count was significantly lower at diagnosis and relapse than during remission times (p < 0.008 and p < 0.000002, respectively). During disease activity either at diagnosis and during relapses, ANCA titers were highly positive (> or =50 IU/ml) in 27.5% of patients (8/29). The corresponding lymphocyte counts were below normal (1,500/min(3)) in 28 of 29 patients (96.5%). In patients with either negative or weakly positive ANCA, mean lymphocyte count was 728.5, 744.2 and 2,551/ml at diagnosis, during relapse and remission times, respectively. There was a clear negative correlation between the lymphocyte count and disease activity. CONCLUSION: Lymphopenia appears to be a good marker of WG activity. This index might be useful in all patients including those with negative ANCA.
Abstract: The prevalence of RAAS in non-insulin-dependent diabetic patients ranges from 17 to 44%. The prevalence increases exponentially in the presence of several risk factors such as severe arterial hypertension, severe renal insufficiency, macroangiopathy, smoking, and insulin requirement. In diabetic patients, RAAS should be investigated in patients with severe arterial hypertension, repeated pulmonary oedemas, and renal insufficiency without any clear etiology associated with a mild proteinuria and/or with a renal insufficiency secondary to the administration of angiotensin converting enzyme inhibitors or angiotensin II receptors antagonists. Asymmetrical size of the kidneys should also prompt the physician with a suspicion of RAAS. There are several specific criteria, that may confirm the suspicion of a RAAS. Renal arteriography is still the goal standard for diagnosing renal artery stenosis.
Abstract: Following intravenous administration, vancomycin is poorly metabolized and is mainly excreted unchanged in urine. Total body clearance is thus dependent on the kidney, and is correlated with glomerular filtration rate and creatinine clearance. Accumulation of vancomycin in patients with renal insufficiency may therefore occur, and this may lead to toxic side effects if dosage is not modified according to the degree of renal failure. Furthermore, vancomycin easily diffuses through dialysis membranes. The aim of the present review is to establish guidelines for handling this drug in such patients. We indicate how and when plasma concentrations of vancomycin should be determined in dialysis patients.
Abstract: BACKGROUND: Abacavir is a potent, novel 2'-deoxyguanosine analogue reverse transcriptase inhibitor (NRTI) which effectively suppresses HIV-1 replication. To date, there is no pharmacokinetic study in patients with renal impairment. METHODS: Five HIV-1-infected patients with various degrees of renal dysfunction (creatinine clearance 60, 40, 25, 20 and 1 haemodialyzed patient) were evaluated after being treated for at least 2 months with multi-antiretroviral therapy including abacavir. After an overnight fast, the subjects received their abacavir dosage (600 or 300 mg). Blood samples were withdrawn and plasma concentrations determined. A nonparametric pharmacokinetic analysis was then performed. The dialysability of abacavir was also evaluated. RESULTS: Time of maximum plasma concentration (T(max)) was constant among the subjects with a mean value of 0.7 +/- 0.27 h (range 0.33-1). Maximum plasma concentration (C(max)) ranged from 2.76 to 4.15 mg/l (mean 3.44 +/- 0.59). The elimination half-life ranged from 1.31 to 2.67 h (mean 2.08 +/- 0.51). Normalized C(max)/dose ranged from 0.007 to 0.014 mg/l and normalized AUC(0-inf)/dose ranged from 0.014 to 0.035 mg.h/l. In haemodialysis the dialysance was 60-80 ml/min with a fractional drug removal of 24% during a 4-hour haemodialysis session with a high permeability membrane. DISCUSSION: In our patients, absorption, elimination and distribution phases were not altered by renal insufficiency. Furthermore, our pharmacokinetic data are similar to those obtained in patients with normal renal function. Therefore, dosage adjustment is not necessary in patients with renal insufficiency. In haemodialyzed patients, treatment can be administered independently to the dialysis session because of the negligible elimination of abacavir in the dialysate.
Abstract: BACKGROUND: Acquired immunodeficiency syndrome (AIDS)-related kidney disorders concern 30% of those patients and can lead to end-stage renal disease (ESRD; 6 to 10%). Therefore, the administration of antiretroviral drugs in human immunodeficiency virus (HIV) patients with nephropathy is not uncommon. METHODS: The influence of ESRD on the different phases of the pharmacokinetic profile of drugs in general is examined in light of bioavailability, distribution, protein binding, metabolism, and elimination. Then, the pharmacokinetics of antiretroviral drugs in hemodialysis are detailed. RESULTS: From these data, dosing recommendations are given for nucleoside reverse transcriptase inhibitors (NRTIs), non-NRTIs, and protease inhibitors (PIs). CONCLUSION: Dosage adjustments are often necessary for patients with renal insufficiency. These adaptations have to be carefully performed to optimize drug exposure and reduce the risk of side effects.
Abstract: Valacyclovir is an effective oral agent for the treatment of herpes virus infection, however, the pharmacokinetics of the drug are altered in renal failure. It is increasingly recognized that dose adjustment of oral valacyclovir in renal failure is necessary to avoid neurotoxicity. We studied this drug in a continuous ambulatory peritoneal dialysis (CAPD) and immunocompromised patient. She developed neurotoxicity with an adjustment dosage of valacyclovir for a cutaneous zoster infection. The elimination half-time (15 h) was similar to that reported for end-stage renal disease patients, while the steady-state volume of distribution (85 l) and the area under the curve concentration (127 mg/l.h) were greater. The mean CAPD dialysance was only 5.27 ml/min with less than 1% of an administered dose being recovered in the 24-hour dialysate. 48 h after interrupting treatment, she recovered normal neurological status and 500 mg of valacyclovir every 2 days was effective and well tolerated.
Abstract: DRUG PHARMACOKINETICS: One of the first steps in the clinical development of drugs consists in studies of their pharmacokinetics. Dosage and administration interval necessary to ensure secure and efficient plasma levels are derived from the values of pharmacokinetic parameters. Renal disease usually implies multiple pathophysiological modifications that generate alteration in drugs pharmacokinetic profile. Those modifications mainly occur on elimination phase but also to a significant extent on absorption and distribution. PATHOPHYSIOLOGICAL CHANGES: In this article we describe potential alteration in drugs absorption, distribution (volume of distribution, binding to plasma proteins), hepatic or renal metabolism, and parent compound and/or metabolites elimination in patients with renal insufficiency. Furthermore, in patients with end-stage renal disease treated by dialysis, drugs are likely to be removed by extracorporal epuration and dosage and/or interval modifications should thus be applied to treatments in those patients. CLINICAL ASSESSMENT: Pharmacokinetics of drugs should be evaluated in patients with renal failure to determine whereas dosage and/or administration interval should thus be modified to enhance tolerance and pharmacological efficacy. Such studies are obviously necessary for drugs that are mainly excreted unchanged in urine. They should also be performed for drugs that are mainly degraded in the liver with emphasis on metabolites pharmacokinetics.
