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

The effect of 6% hydroxyethyl starch 130/0.4 on renal function, arterial blood pressure, and vasoactive hormones during radical prostatectomy: a randomized controlled trial

BACKGROUND

Although hydroxyethyl starch (HES) is commonly used as an intravascular volume expander in surgical patients, recent studies suggest that it may increase the risk of renal failure in critically ill patients. We hypothesized that patients undergoing radical prostatectomy and receiving HES would be more likely to develop markers of renal failure, such as increasing urinary neutrophil gelatinase-associated lipocalin (u-NGAL), creatinine clearance (C(crea)), and decreasing urine output (UO).

METHODS

In a randomized, double-blinded, placebo-controlled study, 40 patients referred for radical prostatectomy received either 6% HES 130/0.4 or saline 0.9%; 7.5 mL/kg during the first hour of surgery and 5 mL/kg in the following hours; u-NGAL, urine albumin, C(crea), UO, arterial blood pressure, and plasma concentrations of creatinine, renin, angiotensin II, aldosterone, and vasopressin were measured before, during, and after surgery.

RESULTS

Thirty-six patients completed the study. u-NGAL, C(crea), UO, plasma neutrophil gelatinase-associated lipocalin, p-creatinine, urine albumin, and arterial blood pressure were the same in both groups. Blood loss was higher in the HES group (HES 1250 vs saline 750 mL), while p-albumin was reduced to a significantly lower level. P-renin and p-angiotensin-II increased in both groups, whereas p-aldosterone and p-vasopressin increased significantly in the saline group.

CONCLUSIONS

We found no evidence of nephrotoxicity after infusion of 6% HES 130/0.4 in patients undergoing prostatectomy with normal preoperative renal function. Hemodynamic stability and infused fluid volume were the same in both groups. We observed an increased blood loss in the group given 6% HES 130/0.4.

Lack of nephrotoxicity by 6% hydroxyethyl starch 130/0.4 during hip arthroplasty: a randomized controlled trial

BACKGROUND

Hydroxyethyl starch (HES) is commonly used as plasma expander during surgery but may be nephrotoxic as seen in studies in patients with sepsis. The authors hypothesized that the possible nephrotoxicity of 6% HES 130/0.4 could be revealed by measurements of urinary excretion of neutrophil gelatinase-associated lipocalin (u-NGAL) in patients with normal renal function during hip arthroplasty.

METHODS

In this randomized, double-blinded, placebo-controlled study, 40 patients referred for hip arthroplasty received either 6% HES 130/0.4 or isotonic saline 0.9%; 7.5 ml/kg during the first hour of surgery and 5 ml/kg during the following hours; 38 patients completed the study. U-NGAL, urine albumin, blood pressure, and plasma concentrations of creatinine, renin, NGAL, albumin, angiotensin-II, and aldosterone were measured before, during, and after surgery. U-NGAL was defined as primary outcome.

RESULTS

There were no significant differences in U-NGAL (mean difference and 95% CI), plasma creatinine, and urine albumin during the study. U-NGAL and urine albumin increased significantly in both groups the morning after surgery but was normalized at follow-up after 10 to 12 days. Mean arterial pressure was significantly higher during the recovery period in the HES group compared with that in the control group (91 [13] and 83 [6] mmHg, mean [SD], P < 0.03). Plasma renin and angiotensin-II were nonsignificantly different in both groups, whereas plasma aldosterone was significantly lower in the HES group. Plasma albumin was reduced in both groups, but to a significantly lower level in the HES group.

CONCLUSION

The study showed no evidence of a harmful effect of intraoperative infusion of 6% HES 130/0.4 on renal function in patients during hip arthroplasty.

Effect of prophylactic versus preemptive lamivudine treatment and tenofovir on HBsAg+ kidney transplant recipients

OBJECTIVES

Chronic hepatitis B virus infection remains a clinical problem for HBsAg (+) kidney transplant recipients. Lamivudine is the approved treatment; however, there are contrary views about optimal initiation. In case of resistance, novel nucleoside analogs should be considered but experience is limited.

MATERIALS AND METHODS

The study was a retrospective cohort study that included 58 HBsAg (+) kidney transplant recipients. Medical records were reviewed for nucleoside analogs, viral replication, and graft/hepatic functions. Prophylactic and preemptive lamivudine modalities were compared to reveal optimal initiation. Additionally, novel nucleoside analogs were evaluated for safety and efficacy.

RESULTS

The graft/patient survival rates for HBsAg (+) recipients were the same as those of hepatitis-free recipients (P = .18). Prophylactic group had 24 and the preemptive had 34 patients. In the prophylactic group, there were fewer hepatic dysfunctions (12.5% vs. 30%, P = .12), viral breakthroughs (16% vs. 32%, P = .17) and elevated alanine aminotransferase concentrations (37% vs. 52%, P = .24), however these did not reach statistical significance. Progressive hepatic dysfunction was observed in 5 patients. Treatment was altered to tenofovir (n = 4) and adefovir (n = 1), and adequate virologic/biochemical response was achieved. These nucleoside analogs were almost as safe as lamivudine, as there were no significant differences among proteinuria (4740 ± 9480 vs 1250 ± 430 mg/L; P = .60) and estimated glomerular filtration rate (1.23 ± 0.37 vs 1.10 ± 0.35 mL/s; P = .33) CONCLUSIONS: Lamivudine is an efficient means of providing comparable graft/patient survival with hepatitis-free kidney transplant recipients. The prophylactic initiation of lamivudine may be better in preventing hepatic dysfunction. Tenofovir can be an effective and safe treatment for lamivudine-resistant kidney transplant recipients.

Review article: nucleos(t)ide analogues in patients with chronic hepatitis B virus infection and chronic kidney disease

BACKGROUND

The treatment of chronic hepatitis B (CHB) in patients with chronic kidney disease (CKD) is based on nucleoside (lamivudine, telbivudine, entecavir) or nucleotide (adefovir, tenofovir) analogues (NAs), but it may be complex and the information is scarce. Entecavir and tenofovir represent the currently recommended first-line NAs for NA-naive CHB patients, while tenofovir is the NA of choice for CHB patients with resistance to nucleosides.

AIM

To review the efficacy and safety of NAs in adult CHB patients with CKD and to provide reasonable recommendations for their optimal management.

METHODS

Literature search in PubMed/Medline and manual search of relevant articles, reviews and book chapters.

RESULTS

NAs are cleared by kidneys and their dosage should be adjusted in patients with creatinine clearance <50 mL/min. There are concerns about nephrotoxic potential of the nucleotides, particularly adefovir, while improvements of creatinine clearance have been reported under telbivudine. Most existing data in CHB patients with CKD are for lamivudine and, less frequently, for other NAs, mostly entecavir. Besides CHB, NA should be used in case of immunosuppressive therapy in any HBsAg-positive patient with CKD including renal transplant (RT) recipients and in anti-HBs-positive recipients of kidney grafts from HBsAg-positive donors.

CONCLUSIONS

Chronic hepatitis B patients with chronic kidney disease receiving nucleoside analogues should be followed carefully for treatment efficacy and renal safety. Despite the absence of strong data, entecavir and telbivudine seem to be the preferred options for nucleoside analogue-naive CHB patients with chronic kidney disease, depending on viraemia and severity of renal dysfunction. More studies are certainly needed in this setting.

Acute Kidney Injury Secondary to NSAID Diagnosed on 99mTc MDP Bone Scan

A bone scan with 99mTc MDP was obtained to rule out the presence of micro fractures in a patient with the diagnosis of idiopathic osteoporosis. There was not any sign of micro fractures, but interestingly, both kidneys were diffusely very active. A differential diagnosis of acute kidney injury secondary to the use of nonsteroidal anti-inflammatory drug was made and reported after elimination of other clinical situations. The renal functions obtained following bone scan were impaired. The anti-inflammatory drug was discontinued. The renal functions were recovered starting with the following day.

Conflict of interest:None declared.

Methodology of a large prospective, randomised, open, blinded endpoint streamlined safety study of celecoxib versus traditional non-steroidal anti-inflammatory drugs in patients with osteoarthritis or rheumatoid arthritis: protocol of the standard care versus celecoxib outcome trial (SCOT)

INTRODUCTION

Cyclooxygenase 2 (COX-2) inhibitors have less upper gastrointestinal toxicity than traditional non-steroidal anti-inflammatory drugs (NSAIDs). However, both COX-2 inhibitors and traditional NSAIDs may be associated with adverse cardiovascular side effects. Data from randomised and observational studies suggest that celecoxib has similar cardiovascular toxicity to traditional NSAIDs. The overall safety balance of a strategy of celecoxib therapy versus traditional NSAID therapy is unknown. The European Medicines Agency  requested studies of the cardiovascular safety of celecoxib within Europe. The Standard care versus Celecoxib Outcome Trial (SCOT) compares the cardiovascular safety of celecoxib with traditional NSAID therapy in the setting of the European Union healthcare system.

METHODS AND ANALYSIS

SCOT is a large streamlined safety study conducted in Scotland, England, Denmark and the Netherlands using the Prospective Randomised Open Blinded Endpoint design. Patients aged over 60 years with osteoarthritis or rheumatoid arthritis, free from established cardiovascular disease and requiring chronic NSAID therapy, are randomised to celecoxib or their previous traditional NSAID. They are then followed up for events by record-linkage within their normal healthcare setting. The hypothesis is non-inferiority with a confidence limit of 1.4. The primary endpoint is the first occurrence of hospitalisation or death for the Anti-Platelet Trialists' Collaboration (APTC) cardiovascular endpoint of non-fatal myocardial infarction, non-fatal stroke or cardiovascular death. Secondary endpoints are (1) first hospitalisation or death for upper gastrointestinal ulcer complications (bleeding, perforation or obstruction); (2) first occurrence of hospitalised upper gastrointestinal ulcer complications or APTC endpoint; (3) first hospitalisation for heart failure; (4) first hospitalisation for APTC endpoint plus heart failure; (5) all-cause mortality and (6) first hospitalisation for new or worsening renal failure.

ETHICS AND DISSEMINATION

SCOT has been approved by the relevant ethics committees. The trial results will be published in a peer-reviewed scientific journal.

CLINICAL TRIALS REGISTRATION NUMBER

Clinicaltrials.gov (NCT00447759).

A novel experience of antiviral therapy for chronic hepatitis B in renal transplant recipients

BACKGROUND

Entecavir (ETV) is a potent inhibitor of viral replication in chronic hepatitis B. There is no published data concerning ETV therapy in nucleoside analogue (NUC)-naive hepatitis B surface antigen (HBsAg)-positive renal transplant recipients (RTRs).

METHODS

We prospectively treated 27 HBsAg-positive RTRs with ETV since 2007. Serial HBV DNA was assessed at baseline and weeks 12, 24, 52 and 104 after treatment. A cohort of 19 patients who received 2-year lamivudine (3TC) therapy during 2004-2007 was used as a historical control.

RESULTS

Of the 27 RTRs, 18 (67%) were NUC-naive patients and 9 (33%) were 3TC-experienced without YMDD mutations. HBV DNA levels became undetectable in 70%, 74%, 96% and 100% of patients after 12, 24, 52 and 104 weeks, respectively, of ETV treatment without viral resistance. There was no change of glomerular filtration rate, and no lactic acidosis or myopathy during treatment. By comparison with the 19 3TC-treated patients, ETV-treated RTRs presented higher rates of undetectable HBV DNA than 3TC-treated RTRs (32%, 37%, 63% and 63% at 12, 24, 52 and 104 weeks; P<0.005). In an analysis excluding 9 patients from the ETV group who were also 3TC-experienced, the remaining 18 ETV-naive RTRs exhibited a better virological response at 52 and 104 weeks than 19 3TC-treated RTRs (P<0.05). Even in the 9 patients who overlapped in two cohorts, ETV exhibited a more rapid virological response than 3TC did, especially at 12 and 24 weeks (P=0.009).

CONCLUSIONS

ETV is effective in treating chronic hepatitis B in RTRs. ETV is safe with regards to renal graft function, lactic acidosis, myopathy and virological resistance.

Proteomic analysis of urine in medication-overuse headache patients: possible relation with renal damages

Medication-overuse headache (MOH) is a chronic disorder associated with overuse of analgesic drugs, triptans, non-steroidal anti-inflammatory drugs (NSAIDs) or other acute headache compounds. Various epidemiologic investigations proved that different drug types could cause nephrotoxicity, particularly in chronic patients. The aim of the present work was to analyze, by a proteomic approach, the urinary protein profiles of MOH patients focusing on daily use of NSAIDs, mixtures and triptans that could reasonably be related to potential renal damage. We selected 43 MOH patients overusing triptans (n = 18), NSAIDs (n = 11), and mixtures (n = 14), for 2–30 years with a mean daily analgesic intake of 1.5 ± 0.9 doses, and a control group composed of 16 healthy volunteers. Urine proteins were analyzed by mono-dimensional gel electrophoresis and identified by mass spectrometry analysis. Comparing the proteomic profiles of patients and controls, we found a significantly different protein expression, especially in the NSAIDs group, in which seven proteins resulted over-secreted from kidney (OR = 49, 95% CI 2.53–948.67 vs. controls; OR = 11.6, 95% CI 0.92–147.57 vs. triptans and mixtures groups). Six of these proteins (uromodulin, α-1-microglobulin, zinc-α-2-glycoprotein, cystatin C, Ig-kappa-chain, and inter-α-trypsin heavy chain H4) were strongly correlated with various forms of kidney disorders. Otherwise, in mixtures and in triptans abusers, only three proteins were potentially associated to pathological conditions (OR = 4.2, 95% CI 0.33–53.12, vs. controls). In conclusion, this preliminary proteomic study allowed us to define the urinary protein pattern of MOH patients that is related to the abused drug. According with the obtained results, we believe that the risk of nephrotoxicity should be considered particularly in MOH patients who abuse of NSAIDs.

Intensive strategy to prevent CMV disease in seropositive umbilical cord blood transplant recipients

Seropositive umbilical cord blood transplant (UCBT) recipients are at increased risk for CMV complications. To reduce CMV complications, we adopted an intensive strategy that consisted of ganciclovir administered before transplantation (5 mg/kg intravenously daily from day -8 to day -2), high-dose acyclovir (2 g, 3 times daily) after transplantation, and biweekly monitoring with a serum CMV PCR for preemptive therapy. Hazard rates and cumulative incidence of CMV complications along with days treated were compared in high-risk CMV-seropositive UCBT recipients who received the intensive strategy and a historical cohort who received a standard strategy. Of 72 seropositive patients, 29 (40%) received standard prophylaxis and 43 (60%) the new intensive approach. The hazard rate (HR) for CMV reactivation was lower for patients receiving the intensive strategy (HR 0.27, 95% confidence interval 0.15-0.48; P < .001) and led to fewer cases of CMV disease by 1 year (HR 0.11, 95% confidence interval 0.02-0.53; P = .006). In patients who reactivated, the intensive strategy also led to fewer days on CMV-specific antiviral therapy (median 42% [interquartile range 21-63] vs 70% [interquartile range 54-83], P < .001). Use of an intensive CMV prevention strategy in high-risk CMVseropositive UCBT recipients results in a significant decrease in CMV reactivation and disease.

Adverse reactions and drug-drug interactions in the management of women with postmenopausal osteoporosis

The pharmacological management of disease should involve consideration of the balance between the beneficial effects of treatment on outcome and the probability of adverse effects. The aim of this review is to explore the risk of adverse drug reactions and drug-drug interactions with treatments for postmenopausal osteoporosis. We reviewed evidence for adverse reactions from regulatory documents, randomized controlled trials, pharmacovigilance surveys, and case series. Bisphosphonates are associated with gastrointestinal effects, musculoskeletal pain, and acute-phase reactions, as well as, very rarely, atrial fibrillation, atypical fracture, delayed fracture healing, osteonecrosis of the jaw, hypersensitivity reactions, and renal impairment. Cutaneous effects and osteonecrosis of the jaw are of concern for denosumab (both very rare), though there are no pharmacovigilance data for this agent yet. The selective estrogen receptor modulators are associated with hot flushes, leg cramps, and, very rarely, venous thromboembolism and stroke. Strontium ranelate has been linked to hypersensitivity reactions and venous thromboembolism (both very rare) and teriparatide with headache, nausea, dizziness, and limb pain. The solidity of the evidence base depends on the frequency of the reaction, and causality is not always easy to establish for the very rare adverse reactions. Drug-drug interactions are rare. Osteoporosis treatments are generally safe and well tolerated, though they are associated with a few very rare serious adverse reactions. While these are a cause for concern, the risk should be weighed against the benefits of treatment itself, i.e., the prevention of osteoporotic fracture.

Current status of antiviral therapy for hepatitis B

Chronic hepatitis B (CHB) is a major public health problem affecting up to 400 million people globally. Complications of CHB including liver failure and hepatocellular carcinoma result in 1.2 million deaths per year, making CHB the 10th leading cause of mortality worldwide. The natural history of CHB is variable and complex. The past decade witnessed important developments for the therapy of hepatitis B and marked the new era of oral therapy. The ultimate goal of CHB therapy is to arrest the progression of liver injury and to prevent the development of liver failure and hepatocellular carcinoma. Currently, six agents are approved for the treatment of CHB. Each of these agents, given as monotherapy, has been shown to produce virological, biochemical, and histological benefits for both HBeAg positive and negative CHB. There are, however, limitations in spite of their efficacy. The significant side-effect profile of interferon, for example, limits its long-term use. The approved oral agents are tolerable with prolonged use but drug resistance could limit long-term monotherapy. To date, combination therapy with nucleoside analogue and pegylated interferon or two nucleos(t)ide analogues given for one year does not show superiority in durability of response compared to monotherapy. Ongoing research effort is critical to identify the ideal hepatitis B therapy that is safe, effective, and produces durable response with a finite course of therapy. It is equally important to conduct a well designed, prospective natural history study to identify predictors of disease progression. This will accurately guide treatment strategy for this important disease.

Endocrine complications of human immunodeficiency virus infection: hypogonadism, bone disease and tenofovir-related toxicity

Treatment with highly active antiretroviral therapy (HAART) has revolutionized care of patients with HIV infection. The cost of increased survival has been antiretroviral toxicity and increasing age-related co-morbidities that include significant metabolic issues. Hypogonadism was first described in the setting of advanced AIDS and can be primary or secondary. Data regarding treatment largely concern patients with wasting. Varied syndromes involving bone have been described in patients with HIV including osteonecrosis, low bone mineral density (BMD) and osteoporosis, and rarely osteomalacia. Low BMD leading to osteoporosis is the most common bone pathology and may be as a result of HIV infection, drug toxicity or co-morbidities. However, increasingly fragility fractures are reported in HIV-infected patients, suggesting bone demineralization in this population is of clinical relevance. Further research is required to understand its pathogenesis and determine effective management; however, initiation of antiretroviral therapy seems to accelerate (in the short-term) bone demineralization. One particular antiretroviral agent, tenofovir is widely used and is potentially implicated as having a greater role in long-term bone and renal dysfunction. As this population ages, screening for low BMD will become increasingly more important.

Clinical profile, genotype and management updates of hepatitis B virus

Hepatitis B virus (HBV) is a well known agent of acute and chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Around 400 million people worldwide carrier of HBV of which more than 250 million reside in Asia, and 1-2 million people have died from it. It has a partially double-stranded DNA, having 3.2-kb genome size and replicate via reverse transcription of RNA intermediate. In the natural history or during the antiviral therapy of chronic HBV infection, seroconversion from HBeAg to anti-HBeAg is usually accompanied by a decrease in viral replication and remission of liver disease. Based on genomic sequence data HBV is classified into eight genotypes A-H and four major serotypes ayw, ayr, adw and adr on the basis of complete genome and S gene sequence analysis. Genotypes and serotypes are useful tools in understanding the epidemiology of HBV infection. HBV genotypes have distinct geographical distributions. The HBV variants appear during HBeAg seroconversion and they bring mutations in the precore region (PC) that prevent HBeAg synthesis. Another common HBeAg variant is the basal core promoter mutant (BCP) characterized by point mutation in the promoter of both HBeAg mRNA and core protein mRNA. The most frequent core promoter mutation is the double A1762T and G1764A nucleotide exchange, which results in a substantial decrease in HBeAg expression but enhanced viral genome replication. The approved antiviral drugs such as Interferon, lamivudine, adefovir dipivoxil, entecavir and telbivudine for purpose of treating chronic HBV infection is to prevent or stop the progression of liver injury by suppressing viral replication or eliminating infection. Sustained losses of viral markers of active viral replication (HBeAg and HBV DNA) are the standard end point of the therapies.

Risk factors of chronic kidney disease in HIV-infected patients

BACKGROUND AND OBJECTIVES

The main aim of this study was determining the risk factors of chronic kidney disease (CKD) in HIV-1-infected patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients were followed from seven large HIV reference centers in France that maintain prospective databases on HIV-1-infected patients. The main outcome was the time to CKD defined as two consecutive measures of estimated GFR ≤60 ml/min per 1.73 m² over ≥3 months. A Cox's model with delayed entry was used to search predictive factors of time to CKD.

RESULTS

From 1993 to 2006, 349 out of 7378 patients were found to have CKD. Of these, 166 had hypertension, 33 had diabetes, and 26 were antiretroviral therapy-naïve. Occurrence of acute kidney injury (hazard ratio [HR] = 2.40) and hypertension (HR = 2.39) were strongly associated with an increased risk of CKD. Patients with a durable level of CD4 count >200 cells/mm³ had a lower risk of CKD (HR = 0.63). Recent exposure to indinavir (HR = 2.03), totenofovir (HR = 1.55), and abacavir (HR = 1.37) were associated with an increased risk of CKD. Past exposure to tenofovir was also associated with an increased risk of CKD (HR = 2.23), and a trend toward significance was observed for past exposure to indinavir (HR = 1.28).

CONCLUSIONS

CKD was not rare in HIV-infected patients and occurs preferentially in HIV-infected patients exposed to certain ARVs, specifically abacavir, indinavir and tenofovir. This requires closer monitoring of renal function in patients exposed to one of these drugs.

Potential pathophysiological mechanisms in osteonecrosis of the jaw

Bisphosphonates are used in the treatment of hypercalcemia of malignancy, skeletal complications associated with metastastic bone disease, Paget's disease, and osteoporosis. Osteonecrosis of the jaw (ONJ) is a recently described clinical condition that has been associated with the use of nitrogen-containing bisphosphonates. Reports describing this entity first appeared in the literature in 2003. While there have been significant numbers of case reports and a limited number of retrospective and prospective studies examining risk factors associated with ONJ, the pathophysiology of this condition remains elusive. In this review, we explore proposed mechanisms underlying ONJ development and identify potential areas for future investigation.

Accidental and iatrogenic causes of acute kidney injury

PURPOSE OF REVIEW

Ingestions and iatrogenic administration of drugs are all too common causes of acute kidney injury. This review will discuss these preventable causes of acute kidney injury.

RECENT FINDINGS

Recent studies have examined the pathophysiology of acute kidney injury by several commonly used drugs. These studies have shown that drugs and toxins can cause acute kidney injury by altering renal hemodynamics, direct tubular injury or causing renal tubular obstruction.

SUMMARY

Knowledge of the drugs that cause acute kidney injury and how this injury is manifested can lead to improved diagnosis and treatment with the ultimate goal of prevention.

Hepatitis B virus infection and renal transplantation

Although the prevalence of chronic hepatitis B virus (HBV) infection has declined in renal transplant recipients (RTRs), it remains a relevant clinical problem with high morbidity and mortality in long-term follow up. A thorough evaluation, including liver biopsy as well as assessment of HBV replication in serum (i.e. hepatitis B e antigen and/or HBV DNA) is required before transplantation. Interferon should not be used in this setting because of low efficacy and precipitation on acute allograft rejection. The advent of effective antiviral therapies offers the opportunity to prevent the progression of liver disease after renal transplantation. However, as far as we are aware, no studies have compared prophylactic and preemptive strategies. To date, the majority of RTRs with HBV-related liver disease have had a high virological and biochemical response to lamivudine use. However, lamivudine resistance is frequent with a prolonged course of therapy. Considering long-term treatment, antiviral agents with a high genetic barrier to resistance and lack of nephrotoxicity are suggested. The optimal strategy in RTRs with HBV infection remains to be established in the near future.

Assessment of the role of renal organic anion transporters in drug-induced nephrotoxicity

In the present review we have attempted to assess the involvement of the organic anion transporters OAT1, OAT2, OAT3, and OAT4, belonging to the SLC22 family of polyspecific carriers, in drug-induced renal damage in humans. We have focused on drugs with widely recognized nephrotoxic potential, which have previously been reported to interact with OAT family members, and whose underlying pathogenic mechanism suggests the participation of tubular transport. Thus, only compounds generally believed to cause kidney injury either by means of direct tubular toxicity or crystal nephropathy have been considered. For each drug, or class of agents, the evidence for actual transport mediated by individual OATs under in vivo conditions is discussed. We have then examined their role in the context of other carriers present in the renal proximal tubule sharing certain substrates with OATs, as these are critical determinants of the overall contribution of OAT-dependent transport to intracellular accumulation and transepithelial drug secretion, and thus the impact it may have in drug-induced nephrotoxicity.

An update on the use of Atripla in the treatment of HIV in the United States

Atripla^® (Gilead Sciences Inc, Foster City, CA, USA and Bristol-Myers Squibb, New York City, NY, USA) is a coformulated single pill composed of efavirenz, emtricitabine, and tenofovir disoproxil, intended as a once-daily potent combination antiretroviral therapeutic agent. Its efficacy is equivalent to the 3 component drugs taken in a combination as single medications. The coformulated antiretroviral regimen can be quite effective in patients whose human immunodeficiency virus is sensitive to all 3 components of Atripla. However, women at risk of pregnancy, already pregnant, or nursing mothers should not take Atripla, due to the teratogenic potential of the efavirenz moiety. Adverse effects are similar to those seen with the constituent medications, including potential central nervous system effects and renal toxicity. Since its US Food and Drug administration approval, prescriptions for Atripla have increased steadily.

Drug-induced acute interstitial nephritis

Acute interstitial nephritis (AIN) is a common cause of acute kidney injury. Many etiologies of AIN have been recognized--including allergic/drug-induced, infectious, autoimmune/systemic, and idiopathic forms of disease. The most common etiology of AIN is drug-induced disease, which is thought to underlie 60-70% of cases. Multiple agents from many different classes of drugs can cause AIN, and the clinical presentation and laboratory findings vary according to the class of drug involved. AIN is characterized by interstitial inflammation, tubulitis, edema, and in some cases, eventual interstitial fibrosis. A definitive diagnosis of AIN can be established only by kidney biopsy. Noninvasive tests such as (67)gallium scintigraphy and testing for eosinophiluria have limited diagnostic utility. The mainstay of therapy for drug-induced AIN is timely discontinuation of the causative agent. Although the benefits of corticosteroid therapy remain unproven, they do appear to have a positive effect in some patients with drug-induced AIN, especially when treatment is initiated early in the course of the disease. In general, the prognosis for drug-induced AIN is good, and at least partial recovery of kidney function is normally observed. Early recognition is crucial because patients can ultimately develop chronic kidney disease.

Renal and urologic emergencies in the HIV-infected patient

Antiretroviral therapy has revolutionized the care of individuals infected with the human immunodeficiency virus (HIV) and has fundamentally altered the scope of the disease. Acute renal failure and chronic kidney disease from medication toxicity and comorbid noninfectious illnesses are just as likely today as end-organ injury from the virus itself. Chronic immunosuppression renders HIV-infected patients vulnerable to any of several unique urological infections not frequently seen in immunocompetent patients. A deeper understanding of renal and urological emergencies in the context of the HIV-infected patient will better prepare the emergency physician to render optimal care to this rapidly expanding and aging patient population.

Development of inpatient risk stratification models of acute kidney injury for use in electronic health records

OBJECTIVE

Patients with hospital-acquired acute kidney injury (AKI) are at risk for increased mortality and further medical complications. Evaluating these patients with a prediction tool easily implemented within an electronic health record (EHR) would identify high-risk patients prior to the development of AKI and could prevent iatrogenically induced episodes of AKI and improve clinical management.

METHODS

The authors used structured clinical data acquired from an EHR to identify patients with normal kidney function for admissions from 1 August 1999 to 31 July 2003. Using administrative, computerized provider order entry and laboratory test data, they developed a 3-level risk stratification model to predict each of 2 severity levels of in-hospital AKI as defined by RIFLE criteria. The severity levels were defined as 150% or 200% of baseline serum creatinine. Model discrimination and calibration were evaluated using 10-fold cross-validation.

RESULTS

Cross-validation of the models resulted in area under the receiver operating characteristic (AUC) curves of 0.75 (150% elevation) and 0.78 (200% elevation). Both models were adequately calibrated as measured by the Hosmer-Lemeshow goodness-of-fit test chi-squared values of 9.7 (P = 0.29) and 12.7 (P = 0.12), respectively.

CONCLUSIONS

The authors generated risk prediction models for hospital-acquired AKI using only commonly available electronic data. The models identify patients at high risk for AKI who might benefit from early intervention or increased monitoring.

Acyclovir-induced renal failure in an obese patient

PURPOSE

A case of acyclovir-induced acute renal failure in an obese patient is described.

SUMMARY

A 60-year-old white man arrived at the emergency department complaining of confusion and disorientation. He was 5 ft 7 in tall and weighed 108.9 kg. His medical and surgical histories included chronic obstructive pulmonary disease (COPD), sleep apnea not requiring biphasic positive airway pressure, obesity, oxygen supplementation, and appendectomy. He also had a history of cyst drainage on the back of his neck, with recent drainage emitting a foul odor, and suffered recurrent herpes cold sores on his chin. A lumbar puncture revealed abnormal cerebral spinal fluid. A diagnosis of herpes encephalitis was considered, and the patient was empirically treated with i.v. acyclovir 1 g over 60 minutes every eight hours, with the dosage based on actual body weight. He was also given moxifloxacin 400 mg i.v. daily for possible COPD exacerbation and doxycycline 100 mg i.v. twice daily for possible leptospirosis meningitis. On hospital day 3, his serum creatinine (SCr) and blood urea nitrogen (BUN) concentrations rose to 2.8 g/dL and 32 mg/dL, respectively. Acyclovir was subsequently discontinued, as were all i.v. antibiotics. On day 7, hydration therapy was initiated, as was therapy to alkalinize the urine, and his neurologic status began to improve. At discharge, the patient's SCr and BUN levels were 3.1 g/dL and 38 mg/dL, respectively. His discharge diagnoses included encephalitis with possible viral origin and acyclovir-induced nephrotoxicity.

CONCLUSION

An obese man receiving excessive doses of i.v. acyclovir developed acute but reversible renal failure.

Impact of tenofovir on renal function in HIV-infected, antiretroviral-naive patients

OBJECTIVE

To better characterize the long-term effects of tenofovir on renal function in a large managed care organization.

METHODS

We performed a retrospective cohort analysis in Kaiser Permanente for years 2002 to 2005 comparing renal function among antiretroviral naïve patients initiating a tenofovir-containing regimen (964 patients) or tenofovir-sparing regimens (683 patients). We evaluated glomerular filtration rate (GFR, [Modification of Diet in Renal Disease equation]), serum creatinine, and the development of renal proximal tubular dysfunction. We report multivariable hazard ratios (HR, Cox modeling) and linear outcomes (repeated measures) with predictors retained if P < 0.10 (backward selection). Potential predictor variables included in multivariate models were age, sex, Black race, baseline laboratories (including CD4 count), history of diabetes mellitus, hypertension, malignancy, hepatitis, and concurrent medications.

RESULTS

Overall, tenofovir-exposed patients had a larger relative decline in GFR through 104 weeks (-7.6 mL/min/1.73 m(2) relative to tenofovir-sparing, P < 0.001); the degree of the difference varied by baseline GFR, with the greatest effect seen in those patients with GFR greater than 80 mL/min/1.73 m(2). Tenofovir-exposed patients had greater development of proximal tubular dysfunction over time (at 52 wk: HR(adjusted) = 1.95 [P = 0.01] and at 104 wk: HR(adjusted) = 5.23 [P = 0.0004]) and had greater risk of medication discontinuation (HR(adjusted) = 1.21, P = 0.02), especially as renal function worsened. Viral control and CD4 count changes were similar between the two groups.

CONCLUSIONS

Tenofovir is associated with greater effect on decline in renal function and a higher risk of proximal tubular dysfunction in antiretroviral naïve patients initiating antiretroviral therapy.

Mechanisms of drug-induced nephrotoxicity

Drug-induced nephrotoxicity is a common complication of several medications and diagnostic agents. It is seen in both inpatient and outpatient settings with variable presentations ranging from mild, reversible injury to advanced kidney disease. Manifestations of drug-induced nephrotoxicity include acid-base abnormalities, electrolyte imbalances, urine sediment abnormalities, proteinuria, pyuria, hematuria, and, most commonly, a decline in the glomerular filtration rate. The mechanisms of drug-induced nephrotoxicity may differ between various drugs or drug classes, and they are generally categorized based on the histological component of the kidney that is affected. Aminoglycoside antibiotics, radiocontrast media, conventional nonselective nonsteroidal anti-inflammatory drugs, and selective cyclooxygenase-2 inhibitors, amphotericin B, and angiotensin-converting enzyme inhibitors have been frequently implicated. This chapter reviews the clinical presentation and basic mechanisms of drug-induced nephrotoxicity.

Prophylactic antivirals may be helpful in prevention of varicella-zoster virus reactivation in myeloma, but are they safe?

PURPOSE

Retrospective analysis of two recent multiple myeloma (MM) clinical trials suggested that the use of bortezomib may be associated with an increased incidence of herpes zoster infections. Therefore, prophylactic use of antivirals has been advocated by some authors. This article explores the potential risks and pitfalls linked to routine acyclovir prophylaxis in bortezomib-treated MM.

SUMMARY

use of antivirals can be associated with important nephro- and neurotoxicity. The nephrotoxicity induced by MM itself and its supportive therapies, superimposed to aging and inherent immunosuppression in myeloma, makes the development of renal impairment even more likely. On the other hand, sensory neuropathy is known to occur both during myeloma progression and in the setting of bortezomib therapy. Furthermore, preexisting nephropathy in MM patients can contribute to the occurrence of serious neurologic toxicity with acyclovir.

CONCLUSIONS

long-term acyclovir prophylaxis in MM patients treated with bortezomib may cause severe renal and neurological toxicity. Prevention of these complications can be achieved through either withholding of the antivirals or a very close monitoring of both neurologic status and renal function in this patient population. This highlights the importance of both clinician's and pharmacist's involvement in optimization of myeloma patient care.

Plasma Cell Dyscrasia with Kappa Light-chain Crystals in Proximal Tubular Cells: A Histological, Immunofluorescent, and Ultrastructural Study

This is a case report of a 56-year-old man with plasma cell dyscrasia who presented with proximal tubulopathy manifested as kappa light-chain crystal deposition in the proximal convoluted tubular cells. This was associated with mild cellular damage. The crystals were seen as negative images with the hematoxylin-eosin and periodic acid-Schiff (PAS) stains. They were identified as kappa light-chains by immunofluorescent imaging and confirmed by immunoelectron microscopy. Ultrastructurally, the crystals appear to be located within lysosomes. No deposits of light-chains were seen elsewhere in the kidney biopsy.

Severe Metabolic Acidosis and Renal Failure in an HIV-1 Patient Receiving Tenofovir

A 55-y-old male developed severe metabolic acidosis and renal failure during tenofovir therapy. Increased tenofovir exposure due to low body weight and chronic stable renal insufficiency could have enhanced the risk of nephrotoxicity, and creatinine clearance should be estimated before initiation of tenofovir.

Acute kidney injury in patients with human immunodeficiency virus infection

PURPOSE OF REVIEW

To present an overview of the epidemiology and etiology of acute kidney injury (AKI) in patients infected with human immunodeficiency virus (HIV).

RECENT FINDINGS

HIV-infected patients are at an increased risk of developing AKI. Potential risk factors for the development of AKI in this patient population include increased HIV viral loads, reduced CD4 cell counts, hepatitis C virus coinfection, a history of diabetes, black race, male gender, and baseline chronic kidney and hepatic disease. Observational studies have found an increased morbidity and mortality in HIV-infected patients who develop AKI. There are diverse etiologies of AKI in HIV-infected patients, with increasing reports of highly active antiretroviral therapy-related nephropathy secondary to tenofovir nephrotoxicity. There have also been recent case reports of HIV-infected patients who develop a unique form of acute interstitial nephritis secondary to diffuse infiltrative lymphocytosis syndrome.

SUMMARY

There are a variety of etiologies of AKI in HIV-infected patients. Prompt diagnosis and treatment of AKI is critical to help prevent morbidity and mortality in this patient population.

A child presenting with acute renal failure secondary to a high dose of indomethacin: a case report

Introduction

Acute renal failure caused by nonsteroidal anti-inflammatory drugs administered at therapeutic doses is generally mild, non-anuric and transitory. There are no publications on indomethacin toxicity secondary to high doses in children. The aim of this article is to describe acute renal failure secondary to a high dose of indomethacin in a child and to review an error in a supervised drug prescription and administration system.

Case presentation

Due to a medication error, a 20-day-old infant in the postoperative period of surgery for Fallot's tetralogy received a dose of 10 mg/kg of indomethacin, 50 to 100 times higher than the therapeutic dose. The child presented with acute, oligo-anuric renal failure requiring treatment with continuous venovenous renal replacement therapy, achieving complete recovery of renal function with no sequelae.

Conclusion

In order to reduce medication errors in critically ill children, it is necessary to develop a supervised drug prescription and administration system, with controls at various levels.

The epidemiology of drug-induced disorders: the kidney

The epidemiology of drug-induced renal disorders is a complex topic. Drug-associated nephrotoxicity accounts for 18 - 27% of all acute kidney injury cases in US hospitals. Medications can affect all aspects of the kidney, and drugs that are associated with renal dysfunction are used commonly in clinical practice. The article reviews six major mechanisms of drug-induced renal dysfunction as well as lists the major medications involved. NSAIDs, aminoglycosides, amphotericin B and calcineurin inhibitors are just some examples of drugs that contribute to renal dysfunction. The medical community must be aware of patient risk factors for nephrotoxicity, as well as the drug's inherent nephrotoxic potential, when prescribing and administering medications.

Novel nucleotide human immunodeficiency virus reverse transcriptase inhibitor GS-9148 with a low nephrotoxic potential: characterization of renal transport and accumulation

Accumulation of antiviral nucleotides in renal proximal tubules is controlled by their basolateral uptake via the human renal organic anion transporters type 1 (hOAT1) and 3 (hOAT3) and apical efflux via the multidrug resistance protein 4 (MRP4). GS-9148 is a novel ribose-modified nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitor, and its oral prodrug GS-9131 is currently being evaluated in the clinic as an anti-HIV agent. To assess the potential of GS-9148 for nephrotoxicity, its mechanism of renal transport, cytotoxicity, and renal accumulation were explored in vitro and in vivo. In comparison with the acyclic nucleotides cidofovir, adefovir, and tenofovir, GS-9148 showed 60- to 100-fold lower efficiency of transport (V(max)/K(m)) by hOAT1 and was 20- to 300-fold less cytotoxic in cells overexpressing hOAT1, indicating its lower hOAT1-mediated intracellular accumulation and reduced intrinsic cytotoxicity. GS-9148 was also relatively inefficiently transported by hOAT3. Similar to acyclic nucleotides, GS-9148 was a substrate for MRP4 as evidenced by its reduced intracellular retention in cells overexpressing the efflux pump. Consistent with these molecular observations, GS-9148 was inefficiently taken up by fresh human renal cortex tissue in vitro and showed a limited accumulation in kidneys in vivo following oral administration of [(14)C]GS-9131 to dogs. Compared to acyclic nucleotide analogs, GS-9148 was also found to have lower net active tubular secretion in dogs. Collectively, these results suggest that GS-9148 exhibits a low potential for renal accumulation and nephrotoxicity.

Therapeutic Approach by a Novel Designed Anti-Inflammatory Drug, M2000, in Experimental Immune Complex Glomerulonephritis

The therapeutic efficacy of novel designed nonsteroidal anti-inflammatory drug, M2000 (beta- D- mannuronic acid) on experimental immune complex glomerulonephritis was evaluated. Bovine serum albumin (BSA) nephritis was induced in rats by a subcutaneous immunization and daily intravenous administration of BSA. M2000 solution (30 mg/kg) was administered intraperitoneally at regular 48-hr 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, blood urea nitrogen, 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. Polymorphonuclear neutrophil leukocytes infiltration and glomerular immune complex deposition were 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 200 microg/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

These findings suggest that treatment with M2000 can reduce proteinuria, diminish antibody production, and suppress the progression of disease in a rat model of immune complex glomerulonephritis.

Diagnosis and management of chronic kidney disease

As the US population has continued to age, the number of patients with chronic kidney disease (CKD) has dramatically increased. Faced with this increase, clinicians need a better understanding of what an elevated serum creatinine level represents and a simple codified approach to evaluating renal failure. Creatinine, a muscle waste product, has an imperfect but predictable association with the glomerular filtration rate (GFR). Although other markers of GFR exist, including cystatin C, urea, inulin, and radioisotopic methods, their role in estimating GFR remains a matter for debate, especially that of cystatin C. Diagnosis and management of CKD are challenges for the nonspecialist. We describe a systematic approach that can be used by the nonspecialist to identify most but not all causes of renal insufficiency. Although this approach should allow for earlier recognition of treatable causes of CKD, it does not eliminate the involvement of a nephrologist in the care and management of the conditions causing the renal insufficiency. The nonspecialist should also be able to recognize the 9 therapies that are helpful in preservation of renal function in all patients with CKD.

Determinants of aciclovir-induced nephrotoxicity in children

BACKGROUND

Aciclovir is the drug of choice for severe systemic herpes virus infections. Nephrotoxicity is one of the clinically significant adverse effects of this drug, but studies examining nephrotoxicity in children are scarce.

OBJECTIVE

To identify risk factors for aciclovir-associated nephrotoxicity in the pediatric population.

PATIENTS AND METHODS

A retrospective review was conducted on all children (mean age 81 months; n = 126 [74 boys]) who were treated with aciclovir in a tertiary center between July 2005 and January 2006 and who met our inclusion criteria. Glomerular filtration rate (GFR) was calculated on the first day of treatment and at the peak measured creatinine level while on therapy, using Schwartz's method.

RESULTS

Aciclovir therapy was associated with a significant increase in serum creatinine levels and a parallel decrease in GFR (n = 93; both p <or= 0.0001). Children with immunosuppression who received a variety of other nephrotoxic drugs exhibited more severe nephrotoxicity than those not receiving nephrotoxic drugs. In multiple regression analysis, the use of nephrotoxic drugs (p = 0.02) and impaired GFR at baseline (p = 0.04) were predictive for nephrotoxicity.

CONCLUSIONS

Within the recommended age-dependent dosage schedule of aciclovir there was no effect of dose per kg, age, or sex on nephrotoxicity. The predictors of aciclovir nephrotoxicity were the concomitant use of nephrotoxic drugs and impaired GFR at baseline.

Potential role of intravenous immunoglobulin in the management of peripartum maternal thrombocytopenia due to various causes

Severe maternal thrombocytopenia resulting in hemorrhage is often associated with high mortality. Three cases of severe maternal thrombocytopenia in association with heparin-induced thrombocytopenia (HIT), HELLP syndrome, and systemic lupus erythematosus (SLE) were successfully managed using intravenous immunoglobulin (IVIG). IVIG can reduce the severity of thrombocytopenia and hemolysis, stabilize lupus activity, prevent peripartum hemorrhage, and shorten hospitalization, but it may induce reversible interstitial nephritis and membranous glomerulonephritis. IVIG may be beneficial in the management of severe peripartum maternal thrombocytopenia in association with HIT, HELLP syndrome, and SLE.

Intensive insulin therapy and pentastarch resuscitation in severe sepsis

BACKGROUND

The role of intensive insulin therapy in patients with severe sepsis is uncertain. Fluid resuscitation improves survival among patients with septic shock, but evidence is lacking to support the choice of either crystalloids or colloids.

METHODS

In a multicenter, two-by-two factorial trial, we randomly assigned patients with severe sepsis to receive either intensive insulin therapy to maintain euglycemia or conventional insulin therapy and either 10% pentastarch, a low-molecular-weight hydroxyethyl starch (HES 200/0.5), or modified Ringer's lactate for fluid resuscitation. The rate of death at 28 days and the mean score for organ failure were coprimary end points.

RESULTS

The trial was stopped early for safety reasons. Among 537 patients who could be evaluated, the mean morning blood glucose level was lower in the intensive-therapy group (112 mg per deciliter [6.2 mmol per liter]) than in the conventional-therapy group (151 mg per deciliter [8.4 mmol per liter], P<0.001). However, at 28 days, there was no significant difference between the two groups in the rate of death or the mean score for organ failure. The rate of severe hypoglycemia (glucose level, < or = 40 mg per deciliter [2.2 mmol per liter]) was higher in the intensive-therapy group than in the conventional-therapy group (17.0% vs. 4.1%, P<0.001), as was the rate of serious adverse events (10.9% vs. 5.2%, P=0.01). HES therapy was associated with higher rates of acute renal failure and renal-replacement therapy than was Ringer's lactate.

CONCLUSIONS

The use of intensive insulin therapy placed critically ill patients with sepsis at increased risk for serious adverse events related to hypoglycemia. As used in this study, HES was harmful, and its toxicity increased with accumulating doses. (ClinicalTrials.gov number, NCT00135473.)

Determination of cytotoxicity of nephrotoxins on murine and human kidney cell lines

The present study investigates renal inner medullary collecting duct (mIMCD3) cells and human embryonic kidney cells (HEK293) for evaluation of cytotoxicity of nephrotoxic compounds. The 24 h LC(50) values for cisplatin, paraquat and ibuprofen in mIMCD3 cells were 135, 155 and 3600 microM, respectively. The 24 h LC(50) values for paraquat and ibuprofen in HEK293 cells were 180 and 1000 microM, respectively. Effects of hyperosmolality on cytotoxicity of paraquat were additive in mIMCD3 cells. These data demonstrate that renal hyperosmolality has an additive effect on cytoxicity of paraquat.

Coincident membranous glomerulonephritis and chronic inflammatory demyelinating polyradiculoneuropathy: Questioning the autoimmunity hypothesis

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and membranous glomerulonephritis (MGN) are both autoimmune disorders that are rarely observed concurrently. We describe a patient who developed MGN nearly 20 years after the onset of CIDP, resulting in a secondary progression of his neuropathy. He responded dramatically to a novel regimen of plasma exchange and methotrexate. We propose a mechanism other than autoimmunity for the coincidence of these disorders and discuss the theoretical superiority of the treatment regimen that he received.