Drug-induced renal failure: update on new medications and unique mechanisms of nephrotoxicity

A composite screening tool for medication reviews of outpatients: general issues with specific examples

Regular performance of medication reviews is prominent among methods that have been advocated to reduce the extent and seriousness of drug-related problems, such as adverse drug reactions, drug-disease interactions, drug-drug interactions, drug ineffectiveness and cost ineffectiveness. Several screening tools have been developed to guide practising healthcare professionals and researchers in reviewing the medication patterns of elderly patients; however, each of these tools has its own limitations. This review discusses a wide range of general prescription-, treatment- and patient-related issues that should be taken into account when reviewing medication patterns by implicit screening. These include generic and therapeutic substitution; potentially superfluous or inappropriate medications; potentially inappropriate dosages or duration of treatment; drug-disease and drug-drug interactions; under-treatment; making use of laboratory test results; patient adherence, experiences and habits; appropriate dosage forms and packaging. A broad selection of specific examples and references that can be used as a basis for explicit screening of medication patterns in outpatients is also offered.

Glomerular nephrotoxicity of aminoglycosides

Aminoglycoside antibiotics are the most commonly used antibiotics worldwide in the treatment of Gram-negative bacterial infections. However, aminoglycosides induce nephrotoxicity in 10-20% of therapeutic courses. Aminoglycoside-induced nephrotoxicity is characterized by slow rises in serum creatinine, tubular necrosis and marked decreases in glomerular filtration rate and in the ultrafiltration coefficient. Regulation of the ultrafiltration coefficient depends on the activity of intraglomerular mesangial cells. The mechanisms responsible for tubular nephrotoxicity of aminoglycosides have been intensively reviewed previously, but glomerular toxicity has received less attention. The purpose of this review is to critically assess the published literature regarding the toxic mechanisms of action of aminoglycosides on renal glomeruli and mesangial cells. The main goal of this review is to provide an actualized and mechanistic vision of pathways involved in glomerular toxic effects of aminoglycosides.

Use of Nuclear Magnetic Resonance Spectroscopy to Assess Renal Dysfunction After Hypertonic-Hyperoncotic Resuscitation in Rats

BACKGROUND

The aim of this study was to evaluate the renal tolerance of a hypertonic-hyperoncotic solution (HHS) administration during uncontrolled hemorrhagic shock (UHS).

METHODS

UHS was produced in rats by a preliminary bleed followed by tail amputation. Hydroxyethylstarch (HHS) 200/0.5 6% in NaCl 7.2% was administered to the HHS groups (n = 20) and normal saline (NS) to the NS group (n = 20). Infusion rates were adjusted to prevent mean arterial pressure (MAP) from falling either below 40 mm Hg in the HHS40 (n = 10) and NS40 groups (n = 10), or below 80 mm Hg in the HHS80 (n = 10) and NS80 groups (n = 10). Data obtained were compared with a sham group and a no resuscitation (NR) group. Nephrotoxicity was evaluated by nuclear magnetic resonance analysis in urine samples.

RESULTS

Survival was 60% in the NS40 group and 40% in the NS80 group, 70% in the HHS40 group, and 60% in the HHS80 group (p = not significant). Within and between target groups of 40 mm Hg MAP and 80 mm Hg MAP, there was no significant difference in survival. The mean values of renal metabolites to creatinine (ct) ratios were not significantly different among the six groups. Principal component analysis showed that the HHS80 group was characterized by an increase in allantoin/ct and urea/ct ratios demonstrating acute renal dysfunction and failure of nitrogen metabolism.

CONCLUSION

In prolonged UHS, an infusion of HHS may not increase the rate of survival. HHS infusion in normotensive resuscitation appears to be associated with renal toxicity.

Evaluation of hypophosphataemia in tenofovir disoproxil fumarate (TDF)-exposed and TDF-unexposed HIV-infected out-patients receiving highly active antiretroviral therapy

OBJECTIVES

Cases of hypophosphataemia (often coincident with renal dysfunction) have been reported in HIV-infected patients taking tenofovir disoproxil fumarate (TDF), but randomized placebo-controlled trials of HIV-infected persons with normal baseline renal function have found a comparable incidence of hypophosphataemia in the TDF and placebo groups. We assessed the incidence of grade 2 and higher hypophosphataemia in the HIV Outpatient Study (HOPS).

METHODS

We analysed a prospective cohort of patients who initiated either a TDF-containing highly active antiretroviral therapy (HAART) regimen [TDF-exposed (TDF+) group; n = 165] or a TDF-sparing HAART regimen [TDF-unexposed (TDF-) group; n = 90], and who had normal baseline phosphate and creatinine values.

RESULTS

The TDF+ and TDF- groups had comparable median follow-up times (10.9 vs 8.8 months, respectively; P = 0.18) and number of phosphate measurements (median = 3 for both) and were similar on most clinical and demographic factors. During follow up, 12.7% of TDF+vs 6.7% of TDF-patients developed grade 2 hypophosphataemia (2.0-2.4 mg/dL), and 2.4% of TDF+ patients vs 0% of TDF-patients developed grade 3 hypophosphataemia (1.0-1.9 mg/dL); none developed grade 4 hypophosphataemia (<1.0 mg/dL). The incidence of grade 2 or higher hypophosphataemia was 16.7 per 100 person-years among TDF+ patients vs 8.0 per 100 person-years among TDF-patients (P = 0.11).

CONCLUSIONS

The incidence of hypophosphataemia was somewhat elevated in HOPS patients who took TDF-containing HAART compared with those who took TDF-sparing HAART during the first 1 to 2 years of observation, but the difference was not statistically significant. Longer follow-up of a larger population is needed to determine if this trend towards an association achieves statistical significance and to evaluate the clinical consequences of hypophosphataemia.

Production of M2000 (β-d-mannuronic acid) and its therapeutic effect on experimental nephritis

The present research introduces the method of Production of M2000 (β-d-mannuronic acid) and its therapeutic effect on experimental model of nephritis. M2000 was produced using enzymatic and chemical procedure on prepared alginate from Pseudomonas fluorescens. The experimental glomerulonephritis was induced in rats by a subcutaneous immunization and daily intravenous administration of bovine serum albumin (BSA). M2000 solution (30mg/kg) was administered intraperitoneally at regular 48-h intervals for 4 weeks. Onset of treatment was day 56. Urinary protein was measured weekly and serum anti-BSA antibody was assessed by ELISA method at different intervals. Animals were killed on day 84 and blood samples and kidney specimens were obtained. Serum (creatinine, BUN, cholesterol, and triglyceride) and urine (protein, urea, and creatinine) determinants were measured at the time of sacrifice. Kidney specimens were processed for light and immunofluorescent microscopic examination. The fibrosarcoma cell line was used for assaying tolerability and matrix metalloproteinase type 2 (MMP-2) activity. MMP-2 activity was assessed using zymography. Our data showed that M2000 therapy could significantly reduce the urinary protein excretion in treated rats versus non-treated controls. Anti-BSA antibody titer was lower in treated rats than in controls at the 12th experimental week. PMN infiltration and glomerular immune complex deposition was less intense in treated rats than in controls. Cytotoxicity analysis of M2000 showed a much higher tolerability compared with other tested drugs (diclofenac, piroxicam and dexamethasone). The inhibitory effect of M2000 in MMP-2 activity was significantly greater than that of dexsamethasone and of piroxicam at a concentration of 200μg/ml. Moreover, the toxicological study revealed that M2000 had no influence on serum (BUN, creatinine, triglyceride and cholesterol) determinants, urinary protein excretion and glomerular histology in healthy group receiving drug.

CONCLUSIONS

In this research, for the first time we introduced the procedure of production of M2000 (β-d-mannuronic acid) and our data suggest that treatment with M2000, as a novel anti-inflammatory drug can reduce proteinuria, diminish antibody production and suppress the progression of disease in experimental model of glomerulonephritis.

Multidrug Resistance Protein 4 Protects Bone Marrow, Thymus, Spleen, and Intestine from Nucleotide Analogue–Induced Damage

Nucleoside-based analogues are mainstays in the treatment of cancer, viral infections, and inflammatory diseases. Recent studies showing that the ATP-binding cassette transporter, multidrug resistance protein 4, is able to efflux nucleoside and nucleotide analogues from transfected cells suggests that the pump may affect the efficacy of this class of agents. However, the in vivo pharmacologic functions of the pump are largely unexplored. Here, using Mrp4(-/-) mice as a model system, and the nucleotide analogue, 9'-(2'-phosphonylmethoxyethyl)-adenine (PMEA) as a probe, we investigate the ability of Mrp4 to function in vivo as an endogenous resistance factor. In the absence of alterations in plasma PMEA levels, Mrp4-null mice treated with PMEA exhibit increased lethality associated with marked toxicity in several tissues. Affected tissues include the bone marrow, spleen, thymus, and gastrointestinal tract. In addition, PMEA penetration into the brain is increased in Mrp4(-/-) mice. These findings indicate that Mrp4 is an endogenous resistance factor, and that the pump may be a component of the blood-brain barrier for nucleoside-based analogues. This is the first demonstration that an ATP-binding cassette transporter can affect in vivo tissue sensitivity towards this class of agents.

Use of the dose, time, susceptibility (DoTS) classification scheme for adverse drug reactions in pharmacovigilance planning

In the process of conceiving a pharmacovigilance plan, as proposed in the International Conference on Harmonisation E2E guideline, the challenge will be how to address possible safety issues with a set of appropriate pharmacovigilance methods. For successful planning, the various and sometimes complex dimensions of the adverse drug reaction in question have to be appropriately described. In order to accommodate these better, a 3-dimensional approach, based on dose, time and patient susceptibility, has recently been proposed (the DoTS model). This approach offers a way of presenting the various dimensions of the problem graphically. The aim of this article is to propose how an extended DoTS model, applied to three different scenarios, could give a better understanding of adverse drug reactions and assist in preparing a pharmacovigilance plan.

Antenatal Herpes Serologic Screening

OBJECTIVE

Calls for universal antenatal type-specific herpes simplex virus (HSV) screening to prevent neonatal herpes have recently increased and would affect the four million pregnant women and their partners annually in the United States. We undertook this review to assess the appropriateness of such screening, making relevant comparisons to established antenatal human immunodeficiency virus (HIV) and hepatitis B virus (HBV) screening programs.

DATA SOURCES

We conducted a full PubMed and bibliographic search for relevant literature in English available from 1966 through February 2006, using the terms "genital herpes," "neonatal herpes," "decision analysis" or "cost-effectiveness analysis," and "herpes and pregnancy" or "antenatal herpes screening." Comparison literature was obtained by replacing "herpes" with "HBV" or "HIV".

METHODS OF STUDY SELECTION

We appraised antenatal type-specific HSV screening using well-established criteria for a good screening program, which we articulated as questions. Of 455 articles we selected those that addressed at least one of the questions and were pertinent to the U.S. population.

TABULATION, INTEGRATION, AND RESULTS

We found that neonatal HSV is rare and its incidence is imprecisely defined. There is a lack of evidence supporting the effectiveness of interventions to prevent maternal acquisition of new infection in late pregnancy, which accounts for 60-80% of neonatal herpes. The consequences of universal screening are incompletely understood but include the potential for unnecessary cesarean deliveries and medical treatment, maternal psychosocial stress, and discord among partners. The available evidence indicates universal screening is not cost-effective. In contrast, antenatal HIV and HBV screening programs better satisfy accepted criteria for screening.

CONCLUSION

On the basis of this appraisal, universal antenatal type-specific HSV screening to prevent neonatal herpes does not adequately satisfy criteria of a good screening program, and we recommend against its adoption.

Acute renal failure due to phenazopyridine (Pyridium) overdose: case report and review of the literature

Phenazopyridine (Pyridium) is a commonly used urinary tract analgesic. It has been associated with yellow skin discoloration, hemolytic anemia, methemoglobinemia, and acute renal failure, especially in patients with preexisting kidney disease. We report a 17-year-old female with vertically transmitted human immunodeficiency virus (HIV) infection, presenting with acute renal failure and methemoglobinemia following a suicidal attempt with a single 1,200 mg ingestion of Pyridium. She had no prior evidence of HIV nephropathy. The patient had a progressive nonoliguric renal failure on the 3rd day following the ingestion. She was treated with N-acetylcysteine, intravenous carnitine, and alkalinization of the urine. Her kidney biopsy revealed acute tubular necrosis with no glomerular changes. After 7 days of conservative management, she was discharged home with normal kidney function. To our knowledge, this is the second smallest amount of Pyridium overdose resulting in acute renal failure with no previous history of kidney disease.

Interaction of methotrexate with organic-anion transporting polypeptide 1A2 and its genetic variants

Methotrexate (MTX) is used in patients with malignant and autoimmune diseases. This drug is primarily excreted unchanged in the urine, and its net excretion occurs via active secretory and reabsorptive processes. We characterized the interaction of MTX with human organic-anion transporting polypeptide transporter (OATP) 1A2, which is expressed in tissues important for MTX disposition and toxicity, such as the intestine, kidney, liver, and endothelial cells of the blood-brain barrier. In Xenopus laevis oocytes expressing OATP1A2, the uptake of the model substrate, estrone-3-sulfate (ES), was enhanced 30-fold compared with uninjected oocytes. MTX uptake in oocytes expressing OATP1A2 was saturable (Km = 457 +/- 118 microM; Vmax = 17.5 +/- 4.9 pmol/oocyte/60 min) and sensitive to extracellular pH. That is, acidic pHs stimulated MTX uptake by as much as 7-fold. Seven novel protein-altering variants were identified in 270 ethnically diverse DNA samples. Four protein-altering variants in OATP1A2 exhibited altered transport of ES and/or MTX. The common variant, protein reference sequence (p.) Ile13Thr, was hyperfunctional for ES and MTX and showed a 2-fold increase in the V(max) for ES. The common variant, p. Glu172Asp, exhibited reduced maximal transport capacity for ES and MTX. p. Arg168Cys was hypofunctional, and p. Asn277DEL was nonfunctional. Because of its expression on the apical membrane of the distal tubule and in tissues relevant to MTX disposition and toxicity, these findings suggest that OATP1A2 may play a role in active tubular reabsorption of MTX and in MTX-induced toxicities. Furthermore, genetic variation in OATP1A2 may contribute to variation in MTX disposition and response.

Effect of concurrent medications on cisplatin-induced nephrotoxicity in patients with head and neck cancer

The goal of this study was to identify clinical characteristics and concurrent medications associated with an increased or decreased incidence of cisplatin-induced nephrotoxicity. The medical records for 62 subjects with head and neck cancer who received cisplatin 100 mg/m2 (day 1) plus fluorouracil 1000 mg/m2 (days 1-5) with or without radiation therapy were reviewed from three medical centers. The demographics, concurrent medication therapy, co-existing illnesses and clinical laboratory values were extracted from the medical records. Nephrotoxicity was defined as a minimum rise in serum creatinine of 0.5 mg/dl or above. The concurrent use of hydrochlorothiazide or multivitamins was associated with a higher incidence of nephrotoxicity after cycle 1. Use of albuterol, atenolol or hydrochlorothiazide was also associated with a higher incidence of nephrotoxicity after cycle 1 or 2. In contrast, subjects prescribed dexamethasone or ondansetron were less likely to experience nephrotoxicity. None of these medications affected treatment response. Race/ethnicity was independently correlated with the incidence of nephrotoxicity; African-American subjects were more likely to develop nephrotoxicity independent of the influence of these concurrent medications. Medications may modulate cisplatin-induced nephrotoxicity by altering the metabolic activation of cisplatin to a nephrotoxin. Genetic differences in the drug-metabolizing enzymes may contribute to the correlation with race. The results from this retrospective study provide data to support a larger prospective study to further investigate the associations between these concurrent medications and cisplatin-induced nephrotoxicity.

Drug-Associated Renal Dysfunction

Acute renal failure (ARF) in patients in the ICU is associated with a high mortality. Drug-induced renal dysfunction is an important, yet often overlooked, cause of ARF in this patient population. A drug use evaluation at the authors' institution, to assess the prescribing patterns of potential nephrotoxins in the adult and pediatric ICUs, found that antibiotics (aminoglycosides, amphotericin B, penicillins, cephalosporins, acyclovir), nonsteroidal anti-inflammatory drugs, contrast dye, and various other nephrotoxic medications are used widely in all of the ICUs. By focusing on several commonly prescribed classes of nephrotoxic medications in the ICU, this article reviews the general mechanisms of drug-associated renal dysfunction.

Intermediate-dose cidofovir without probenecid in the treatment of BK virus allograft nephropathy

BK virus allograft nephropathy (BKVAN) is a rising complication in kidney transplant recipients. Reducing immunosuppression has been the initial form of therapy in most cases, but is not always associated with improvement in graft function. Anti-viral therapy with low-dose cidofovir (0.25-0.42 mg/kg/dose) has been used successfully in some patients, but dose-related nephrotoxicity has limited its use. We present our experience with 3 kidney transplant recipients diagnosed with BKVAN who received intermediate-dose cidofovir (0.75-1.0 mg/kg/dose) without probenecid, and without concomitant nephrotoxicity. Three female patients, ages 8, 19 and 20 yr, presented with elevated serum creatinine (SCr) values, BK virus stain positive on renal biopsy and high plasma BK viral loads. As a result of viral loads being >2 million copies/ml in two patients and a lack of response to reduction in immunosuppression in the third, we initiated therapy with low-dose cidofovir. Because of persistent positive BK stain and positive plasma viral load, we then administered intermediate-dose cidofovir, without probenecid, for several subsequent doses (seven to 15 infusions till date). All patients tolerated the intermediate-dose cidofovir with no significant rise in SCr during the course of the infusions. The most recent SCr values in all three patients were improved from those at the initial diagnosis of BKVAN. All three patients showed a marked drop in BK viral loads when on intermediate-dose cidofovir, with complete clearing of viremia in two patients. In our experience, intermediate-dose cidofovir without probenecid, used judiciously, is not associated with additional nephrotoxicity and may provide an additional alternative for treatment.

Renal dysfunction with tenofovir disoproxil fumarate-containing highly active antiretroviral therapy regimens is not observed more frequently: a cohort and case-control study

BACKGROUND

Tenofovir disoproxil fumarate (tenofovir DF), the first nucleotide analogue reverse transcriptase inhibitor approved for the treatment of HIV infection, has been associated with renal dysfunction in isolated cases. We investigated the overall incidence and risk of renal dysfunction in individuals receiving tenofovir DF and compared this with other antiretrovirals.

METHODS

Data from the Chelsea and Westminster cohort were analyzed to reveal HIV-positive individuals with a creatinine value greater than 120 micromol/L at any time, the upper limit of normal used by our reference laboratory. These individuals were classified according to antiretroviral exposure and time exposed. A matched case-control study was performed comparing patients who had received tenofovir DF and subsequently developed a creatinine value greater than 120 micromol/L against controls who had been treated with tenofovir DF and had not experienced a creatinine elevation.

RESULTS

Of 4183 HIV-positive patients, 1175 were identified as having a recorded creatinine value >120 micromol/L. Comparison of antiretroviral-naive patients and patients exposed to tenofovir DF- and non-tenofovir DF-containing regimens revealed a lower rate ratio and probability of developing a creatinine value >120 micromol/L in patients exposed to tenofovir DF (rate ratio vs. no antiretrovirals = 0.22, 95% confidence interval [CI]: 0.07-0.69; P < 0.001) with no significant difference between HAART regimens, corrected for duration of exposure. Of the 1058 individuals who were exposed to tenofovir DF, 84 (8%) patients experienced a creatinine value >120 micromol/L subsequent to exposure. An alternative etiology of renal dysfunction was found in 75 (90%) of these individuals.

CONCLUSIONS

Tenofovir DF is not associated with renal dysfunction more frequently than other antiretroviral drugs, and the occurrence of renal dysfunction in this context is usually attributable to other causes.

Exploring Mitochondrial Nephrotoxicity as a Potential Mechanism of Kidney Dysfunction among HIV-Infected Patients on Highly Active Antiretroviral Therapy

Background

Tenofovir (TDF) exposure has been associated with renal dysfunction. Mitochondrial nephrotoxicity was investigated as an underlying mechanism. Given the interaction between TDF and didanosine (ddI), their concurrent use was also investigated.

Design

Relative kidney biopsy mitochondrial DNA (mtDNA) to nuclear DNA ratios were measured retrospectively. HIV+ individuals on TDF within 6 months preceeding the biopsy (HIV+/TDF+, n=21) were compared to HIV+ individuals who never received TDF (HIV+/TDF-, n=10) and to HIV uninfected controls (HIV–, n=22). Twelve of the HIV+/TDF+ individuals received concurrent ddI, 10 of those once at unadjusted ddI dosage. Tubular mitochondria morphology was also examined by electron microscopy. Statistical analyses were done on log-transformed mtDNA/nDNA, using non-parametric tests.

Results

Kidney mtDNA levels were different among the three groups ( P=0.046). mtDNA ratios were lower in HIV+/TDF+ subjects (7.5 [2.0–12.1]) than in HIV- ones (14.3 [6.0–16.5], P=0.014), but not lower than HIV+/TDF-controls (6.4 [2.8–11.9], P=0.82). Among HIV+ subjects, there was a difference between TDF-, TDF+/ddI- and TDF+/ddI+ ( P=0.005), with concurrent TDF/ddI use associated with lower mtDNA (2.1 [1.9–5.5], n=12) than TDF+/ddI- (13.8 [7.5–16.4], n=9, P=0.003). No TDF–/ddI+ biopsies were available. In regression analyses, only HIV infection ( P=0.03), and TDF/ddI use ( P=0.003) were associated with lower mtDNA. At the ultrastructural level, abnormal tubular mitochondria was more prevalent in HIV+/TDF+ biopsies than HIV+/TDF- and HIV- ones together ( P<0.001) but not more so in TDF+/ddI+ biopsies than TDF+/ddI- ones ( P=0.67).

Conclusions

Renal dysfunction in this population may be mediated through mitochondrial nephrotoxicity that involves more than one drug and/or pathogenesis. Kidney mtDNA depletion was associated with HIV infection and concurrent TDF/ddI therapy but not TDF use alone, while kidney ultrastructural mitochondrial abnormalities were seen with TDF use. The interaction between TDF and ddI may be relevant in the kidney where both drugs are cleared. The clinical relevance of our findings needs to be evaluated given the current recommendation for reduced doses of ddI when used in conjunction with TDF.

Insuffisance rénale aiguë après application topique de sulfadiazine argentique

INTRODUCTION

Prolonged topical application of silver sulfadiazine cream can induce argyria and adverse effects of sulphonamides. We report a case of a woman with acute renal failure following repeated applications of topical silver sulfadiazine on pyoderma gangrenosum wounds.

CASE REPORT

A 61 year-old woman suffering from rheumatoid arthritis, Sjogren's syndrome and scleroderma was treated with corticosteroids (1 mg/kg/day) and topical application of silver sulfadiazine cream (200 g/day) for extensive pyoderma gangrenosum wounds on the legs. Three weeks later, the patient was transferred to intensive care because of pulmonary edema, oligoanuria and disrupted consciousness. Laboratory data revealed leukopenia (1100/mm(3)) with neutropenia and renal failure (serum creatinine 316 micromol/l). Proteinuria was moderate and ultrasonography of the kidneys was normal. Silver concentration in blood was 1818 nmol/l (N < 92 nmol/l) and 1381 nmol/l (N < 9 nmol/l) in urine. Sulfadiazine concentration in blood was undetectable. All the signs regressed after withdrawal of silver sulfadiazine and after several sessions of hemodialysis.

DISCUSSION

Various causes of renal failure are discussed in our patient. However, direct silver-induced renal toxicity is the most likely and is confirmed by the high concentration of silver in blood and urine and the improvement on withdrawal of the topical cream, without modification in the oral treatment. The absence of red corpuscles and crystals in the urine and undetectable concentrations of sulfadiazine in blood are not in favor of sulphonamide renal toxicity. Furthermore, the autoimmune diseases of our patient were well-controlled. Leukopenia could be secondary to silver sulfadiazine medullar toxicity. This observation confirms that this topical cream should not be used for long periods on extensive wounds.

Treatment of experimental arthritis with M2000, a novel designed non-steroidal anti-inflammatory drug

The current study was planned to explore the therapeutic potency of M2000 (beta-D-mannuronic acid), a novel designed non-steroidal anti-inflammatory drug (NSAID) in adjuvant-induced arthritis model. Arthritis was induced in Lewis rats by a single intradermal injection (0.1 ml) of heat-killed Mycobacterium tuberculosis (0.3 mg) in Freund's incomplete adjuvant into the right footpad. Fourteen days after injection of adjuvant, the contralateral left footpad volume was measured. The animals with paw volumes 0.37 ml greater than normal paws were then randomized into treatment groups. Orally and intraperitoneally administrations of test drugs (M2000, 40/mg/kg/day and indomethacin, 2/mg/kg/day) were started on day 15 post-adjuvant injection and continued until final assessment on day 25. The left hind limb was removed for histological evaluation. The WEHI-164 cell line was used for assaying tolerability and matrix metalloproteinase type 2 (MMP-2) activity. MMP-2 activity was assessed using zymography. Pharmacotoxicology study was carried out on animal models based on the evaluation of serum and urine determinants, histology of kidney, gastrointestinal tolerability and body temperature. Results showed that the orally administration as well as intraperitoneally injection of M2000 to arthritic rats induced a significant reduction in paw oedema. Histopathological assessment showed a reduced inflammatory cells infiltrate in joints of treated rats, as well as the number of osteoclasts present in the subchondral bone, tissue oedema and bone erosion in the paws were markedly reduced following M2000 therapy. Cytotoxicity analysis of M2000 showed a much higher tolerability compared with other tested drugs (diclofenac, piroxicam and dexamethasone). The inhibitory effect of M2000 in MMP-2 activity was significantly greater than that of dexamethasone and of piroxicam at a concentration of 200 microg/ml. Moreover, the toxicological study revealed that M2000 had no influence on serum (blood urea nitrogen, creatinine, triglyceride and cholesterol) and urine (urea and urinary protein excretion) determinants, glomerular histology and body temperature in normothermic rats and had no ulcerogenic effects on rats' stomach. Our data show that M2000, as a novel NSAID, could be strongly suggested as the safest anti-inflammatory drug for long-term administration.

M-2000, as a new anti-inflammatory molecule in treatment of experimental nephrosis

The therapeutic effect of M-2000 (C6H10O7) molecule was tested in Adriamycin-induced nephropathy. To induce experimental nephrosis, Adriamycin was given once by a single intravenous injection (7.5 mg/kg) through the tail vein. Six days after injection of Adriamycin, therapeutic protocol was developed by intraperitoneally (i.p) administration of 30 mg/kg M-2000 solution. Total of i.p. injections were 14, in which five injections were made every day and nine injections were carried out at regular 48-h intervals. Therapeutic protocol was terminated on day 28 and animals were killed on day 43. The treated patient rats showed a significant reduction in proteinuria, BUN, serum creatinine and serum cholesterol, as well as, administration of M-2000 could significantly diminish the serum level of interleukin-6 (IL-6) in treated animals compared to non-treated controls. Moreover, treatment with M-2000 significantly reduced number of glomerular leukocytes, Hypercellularity and hydropic change in capillary network within the renal cortex and decreased tubular casts. These data suggest that M-2000 therapy can ameliorate proteinuria, and suppress the progression of glomerular lesions in experimental model of nephrosis.

Hyponatremia in elderly patients treated with desmopressin for nocturia: a review of a case series

OBJECTIVE

Lately, desmopressin (dDAVP) administered orally has been demonstrated to be an effective alternative in the management of nocturia in adults. Although the safety profile of dDAVP is well known, much of the experience originates from studies in enuretic children and younger adults, and it may not be readily extrapolated to elderly patients. In order to identify factors associated with an increased risk of hyponatremia in elderly patients treated with dDAVP for nocturia, we analysed spontaneous reports accrued from clinical practice in Denmark and Sweden.

METHOD

Following a selection procedure, the study base comprised 15 case reports. From the included reports, information was sought on concurrent diseases, concomitant medications and other factors that may predispose elderly patients to hyponatremia when treated with desmopressin.

RESULTS

The median age amongst the cases was 81 years (range 61-93 years) and 80% were females. For seven of the patients, the hyponatremia occurred during the first 3 weeks of treatment. The symptoms presented by the patients led to hospitalisation in all but one case. Among patients with information available on concomitant medication, half of them were treated with cyclooxygenase inhibitors. An excessive fluid intake could only be ascertained in one case; all 15 patients eventually recovered.

CONCLUSION

In elderly patients treated with dDAVP for nocturia, an increased risk of hyponatremia exists in the first weeks of treatment. Compared with younger subjects, risk factors other than excessive intake of fluid appear to contribute to this adverse drug reaction.

Antiviral Drug-Induced Nephrotoxicity

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.

Renal transplants from non-heart beating paracetamol overdose donors

INTRODUCTION

Non-heart beating donors (NHBD) are widely encouraged to avert the critical shortage in the kidney donor pool. Ischaemic injury at the time of cardiac arrest in the NHBD is more pronounced and therefore the kidneys resulting are considered marginal. This review describes our experience with four kidneys from two controlled NHBDs who were exposed to paracetamol intoxication and subsequently were treated with mannitol prior to organ donation.

MATERIALS AND METHOD

Two patients with fulminant liver failure following paracetamol overdose were referred as 'withdrawal of treatment' NHBD. As the two patients had developed hepatic encephalopathy they were treated with mannitol to reduce intra-cerebral oedema. The two donors were oligoanuric for at least 24 h prior to cardiac arrest. Following cardiac arrest, in situ perfusion was carried out and the kidneys were removed. One pair of kidneys were machine perfused while the second pair of kidneys were cold stored prior to transplantation.

RESULTS

Pre-transplant assessment of NHBD kidneys resulted in three of four kidneys being transplanted. The NHBD kidneys exhibited a period of delayed graft function (DGF). The early transplant biopsies showed evidence of diffuse cytoplasmic vacuolation. These histological features disappeared with time and the renal function improved until the time of discharge.

DISCUSSION

Non-heart beating donor kidneys are considered marginal and the effect of mannitol and paracetamol drug intoxication will induce reversible sub-lethal injury. A period of dialysis is inevitable in clearing the reactive intermediates of mannitol and paracetamol. The kidneys behaved as traditional controlled NHBD at time of discharge.

Pharmacokinetics of Enfuvirtide in a Patient with Impaired Renal Function

Enfuvirtide is the first member of the fourth class of antiretroviral drugs to become available. We present a case report of a human immunodeficiency virus (HIV)-positive patient with mild renal impairment who developed severe renal impairment secondary to tenofovir therapy while receiving enfuvirtide. Because the patient's pharmacokinetic profile was not significantly altered, compared with that of HIV-infected patients with normal renal function, no dose modifications were required.

Sulfadiazine-induced nephrolithiasis in children

Sulfadiazine-associated urinary calculi have been described in HIV-positive adult patients but rarely in children. We report two pediatric cases of sulfadiazine-induced nephrolithiasis and review 45 adult cases from the literature. One had a hyper-IgM syndrome and was treated with sulfadiazine for cerebral toxoplasmosis, the other had toxoplasmic retinitis. Both developed multiple bilateral lithiasis with acute renal failure. Normalization of renal function and reduction of calculi size was rapidly achieved after discontinuation of sulfadiazine, hyperhydration, and alkalinization. Bilateral ureteral stents were required in one patient because of anuria.

Mitochondrial toxicity of NRTI antiviral drugs: an integrated cellular perspective

Highly active antiretroviral therapy (HAART) regimes based on nucleoside reverse transcriptase inhibitors (NRTIs) have revolutionized the treatment of AIDS in recent years. Although HAART can successfully suppress viral replication in the long term, it is not without significant toxicity, which can seriously compromise treatment effectiveness. A major toxicity that has been recognized for more than a decade is NRTI-related mitochondrial toxicity, which manifests as serious side effects such as hepatic failure and lactic acidosis. However, a lack of understanding of the mechanisms underlying mitochondrial toxicity has hampered efforts to develop novel drugs with better side-effect profiles. This review characterizes the pharmacological mechanisms and pathways that are involved in mitochondrial dysfunction caused by NRTIs, and suggests opportunities for future pharmacological research.