An appraisal of antiretroviral drugs in hemodialysis

Removal of doravirine by haemodialysis in people living with HIV with end-stage renal disease

Objectives

To evaluate the effect of haemodialysis on doravirine concentrations in people living with HIV (PLWH) undergoing routine haemodialysis.

Methods

An exploratory clinical trial that included PLWH undergoing intermittent haemodialysis was undertaken. After enrolment (day 1), doravirine 100 mg once daily was added to stable combined ART for 5 days. On day 6, blood samples were collected from each participant at the beginning and at the end of a dialysis session. Additionally, paired samples of blood entering (‘in’) and leaving (‘out’) the dialyser and the resulting dialysate were collected during the dialysis session to evaluate drug removal during dialysis. Doravirine concentrations in plasma and in the dialysate were determined by LC-MS/MS. The ratio of doravirine concentrations in plasma after/before the haemodialysis session and the haemodialysis extraction coefficient were calculated for each participant. The study was registered at https://www.clinicaltrials.gov (NCT04689737).

Results

Eight participants (six male) were included. The median (range) age and BMI were 49.5 (28–67) years and 23.6 (17.9–34.2) kg/m2, respectively. The doravirine dialysis extraction ratio was 34.3% (25.8%–41.4%). The ratio of doravirine concentrations in plasma after/before the haemodialysis session was 0.8 (0.6–1.0). At the end of the haemodialysis session (time post-dose 20.8–27.3 h), doravirine concentrations in plasma were 785 (101–1851) ng/mL.

Conclusions

Despite moderate removal of doravirine by haemodialysis, trough doravirine concentrations in plasma after the haemodialysis sessions remained in excess of the protein-binding-adjusted EC50 (5 ng/mL). Doravirine dosage adjustments are unnecessary in PLWH undergoing intermittent haemodialysis.

High-Throughput Metabolomics and Diabetic Kidney Disease Progression: Evidence from the Chronic Renal Insufficiency (CRIC) Study

INTRODUCTION

Metabolomics could offer novel prognostic biomarkers and elucidate mechanisms of diabetic kidney disease (DKD) progression. Via metabolomic analysis of urine samples from 995 CRIC participants with diabetes and state-of-the-art statistical modeling, we aimed to identify metabolites prognostic to DKD progression.

METHODS

Urine samples (N = 995) were assayed for relative metabolite abundance by untargeted flow-injection mass spectrometry, and stringent statistical criteria were used to eliminate noisy compounds, resulting in 698 annotated metabolite ions. Utilizing the 698 metabolites' ion abundance along with clinical data (demographics, blood pressure, HbA1c, eGFR, and albuminuria), we developed univariate and multivariate models for the eGFR slope using penalized (lasso) and random forest models. Final models were tested on time-to-ESKD (end-stage kidney disease) via cross-validated C-statistics. We also conducted pathway enrichment analysis and a targeted analysis of a subset of metabolites.

RESULTS

Six eGFR slope models selected 9-30 variables. In the adjusted ESKD model with highest C-statistic, valine (or betaine) and 3-(4-methyl-3-pentenyl)thiophene were associated (p < 0.05) with 44% and 65% higher hazard of ESKD per doubling of metabolite abundance, respectively. Also, 13 (of 15) prognostic amino acids, including valine and betaine, were confirmed in the targeted analysis. Enrichment analysis revealed pathways implicated in kidney and cardiometabolic disease.

CONCLUSIONS

Using the diverse CRIC sample, a high-throughput untargeted assay, followed by targeted analysis, and rigorous statistical analysis to reduce false discovery, we identified several novel metabolites implicated in DKD progression. If replicated in independent cohorts, our findings could inform risk stratification and treatment strategies for patients with DKD.

Changes in serum concentration of rilpivirine in an HIV-infected patient treated with a combination therapy of hemodialysis and peritoneal dialysis

Background

To our knowledge, there are no preexisting reports concerning rilpivirine (RPV) removal by hemodialysis and peritoneal dialysis.

Case presentation

This study aimed to evaluate the effect of hemodialysis and peritoneal dialysis on plasma concentrations of RPV in a 45-year-old man infected with HIV and exhibiting end-stage renal disease (ESRD). The extraction ratio of RPV by hemodialysis was 4.5%. Plasma concentrations of RPV remained far above the protein-binding-adjusted inhibitory levels during a combination therapy of hemodialysis and peritoneal dialysis. Our results suggest minimal RPV removal via hemodialysis and peritoneal dialysis with no specific dosage adjustments required in an HIV-infected patient undergoing this combination therapy.

Conclusion

In conclusion, this study showed that RPV administered without dose adjustment resulted in steady-state plasma drug concentration in an HIV-infected patient treated with a combination therapy of hemodialysis and peritoneal dialysis.

Safety of elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide in HIV-1-infected adults with end-stage renal disease on chronic haemodialysis: an open-label, single-arm, multicentre, phase 3b trial

BACKGROUND

Current treatment for HIV-infected individuals with renal failure on haemodialysis frequently requires complex regimens with multiple pills. A daily single-tablet regimen of coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide is approved in Europe, the USA, and in other regions for use in HIV-1-infected individuals with mild-to-moderate chronic kidney disease (creatinine clearance 30-69 mL/min). We aimed to assess the safety, efficacy, and pharmacokinetics of this regimen in HIV-infected adults with end-stage renal disease on chronic haemodialysis.

METHODS

We did an open-label, single-arm, multicentre, phase 3b trial at 26 outpatient clinics in Austria, France, Germany, and the USA. Participants were HIV-1-infected adults with end-stage renal disease (creatinine clearance <15 mL/min), on chronic haemodialysis for at least 6 months before screening. Virological suppression (ie, plasma HIV-1 RNA <50 copies per mL) on a stable antiretroviral regimen was required for at least 6 months before screening with a CD4 count of at least 200 cells per μL. We switched all participants to coformulated elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, and tenofovir alafenamide 10 mg once daily, taken after haemodialysis for up to 96 weeks. We did assessments at study visits at weeks 2, 4, 8, 12, 24, 36, and 48, and every 12 weeks thereafter up to 96 weeks. The primary endpoint was the incidence of treatment-emergent adverse events of grade 3 or higher up to week 48. All participants who received at least one dose of study drug were included in the primary analysis. This study is registered with ClinicalTrials.gov (NCT02600819) and is closed to new participants.

FINDINGS

Between Feb 1, and Nov 3, 2016, 55 participants were enrolled and received at least one dose of study drug. Through week 48, 18 of 55 participants (33%, 95% CI 20-45) had an adverse event of grade 3 or higher on study treatment. Treatment-emergent grade 3 or higher adverse events that occurred in more than one participant included anaemia, osteomyelitis, prolonged electrocardiogram QT, fluid overload, hyperkalaemia, hypertension, and hypotension (all n=2). No adverse event of grade 3 or higher was considered by the site investigators to be treatment related. Three participants (5%, 95% CI 0-11) discontinued treatment because of adverse events; one of these (grade 1 allergic pruritus) was considered treatment related. Treatment-related adverse events were reported for six individuals (11%, 95% CI 3-19), the most common of which was nausea (in four individuals [7%]); all treatment-related adverse events were grade 1 or 2 in severity.

INTERPRETATION

At 48 weeks, switching to the single-tablet regimen of elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide was well tolerated. This regimen might provide a tolerable and convenient option for ongoing treatment of HIV-1 infection in adults with end-stage renal disease on chronic haemodialysis.

FUNDING

Gilead Sciences.

The Management of Viral Hepatitis in CKD Patients: An Unresolved Problem

Chronic kidney disease (CKD) patients in dialysis (HD) show peculiar, atypical features of clinical presentation and diseases (cardiovascular, metabolic, hematologic). This is also true for viral hepatitis infections, for which CKD patients represent an important risk group. In the past, hepatitis B virus (HBV) was the major cause of viral hepatitis in end-stage renal disease (ESRD). However, the introduction of a rigorous infection-control strategy, routine screening of patients and staff for hepatitis B serologic markers, vaccination of susceptible patients and staff, use of separate rooms and dedicated machines for HD of HbsAg-positive patients have all led to a decline in the spread of HBV infection in dialysis. Despite the prevalence of the antibody-hepatitis C virus (HCV), there has been a marked decrease in HD patients; after the introduction of routine screening for HCV and the use of erythropoietin, its occurrence ranges from 5% to 25% in the United States, with a prevalence of 6.8% in Europe. In CKD and in HD patients, the presence of HBV and HCV is an independent and significant risk factor for death and this risk may be at least partially attributed to chronic liver disease with its attendant complications. Liver disease can progress with modest hepatic inflammation and prominent fibrosis; the natural history of viral hepatitis in these patients is dependent on the immune dysfunction typical of kidney disease. Despite recent advances in antiviral therapy, there are still many uncertainties in regards to the efficacy and long-term outcomes of treatment with antiviral agents.

The effect of veno-venous ECMO on the pharmacokinetics of Ritonavir, Darunavir, Tenofovir and Lamivudine

INTRODUCTION

To our knowledge, there is no published data on the pharmacokinetic (PK) profile of antiretroviral (ART) drugs on patients undergoing extracorporeal membrane oxygenation (ECMO) therapy. We present PK analyses of Ritonavir, Darunavir, Lamivudine and Tenofovir in a patient with HIV who required veno-venous ECMO (VV ECMO).

METHODS

Plasma concentrations for Ritonavir, Darunavir, Tenofovir and Lamivudine were obtained while the patient was on ECMO following pre-emptive dose adjustments. Published population PK models were used to simulate plasma concentration profiles for the drugs. The population prediction and the observed plasma concentrations were then overlaid with the expected drug profiles using the individual Bayesian post-hoc parameter estimates.

RESULTS

Following dose adjustments, the PK profiles of Ritonavir, Darunavir and Tenofovir fell within the expected range and appeared similar to the population prediction, although slightly different for Ritonavir. The observed data for Lamivudine and its PK profile were completely different from the data available in the literature.

CONCLUSIONS

To our knowledge, this is the first study reporting the PK profile of ART drugs during ECMO therapy. Based on our results, dose adjustment of ART drugs while on VV ECMO may be advisable. Further study of the PK profile of Lamivudine is required.

Renal Transplantation in HIV-positive Renal Transplant Recipients: Experience at the Mannheim University Hospital

Renal transplantation in HIV-positive patients with end-stage renal disease has in recent years become a successful treatment option. We report two patients who underwent renal transplantation using a combination of basiliximab, calcineurin inhibitors, mycophenolate mofetil (MMF), and steroids with a "non-interacting" antiretroviral combination therapy consisting of stavudine or abacavir, lamivudine, and nevirapine. We observed no acute rejection but a BK polyomavirus infection in both patients. In conclusion, a quadruple immunosuppression with an interleukin 2 receptor antagonist, a calcineurin inhibitor, MMF, and steroids appears to be advisable to prevent high rates of acute rejection, but if possible thereafter immunosuppression should be tapered rapidly (eg, MMF stop, prednisolone dose 5 mg/d). The selection of antiretroviral agents should avoid compounds that interact severely with the immunosuppression used.

Dosing nucleoside reverse transcriptase inhibitors in adults receiving continuous veno-venous hemofiltration

BACKGROUND AND OBJECTIVE

Characteristics of nucleoside reverse transcriptase inhibitors (NRTIs) make the drug class susceptible to elimination via continuous veno-venous hemofiltration (CVVH), potentially leading to suboptimal drug concentrations if given at the recommended anephric doses during CVVH. The objective of this study was to formulate NRTI dosing recommendations for adults receiving CVVH.

METHODS

A mathematical formula that estimates the amount of drug likely to be removed during CVVH at various flow rates was used to calculate the supplemental NRTI dose required during CVVH.

RESULTS

A proposed table of dosing recommendations for NRTIs during CVVH is presented.

CONCLUSION

Clinicians should utilize these recommendations in the context of each individual patient, taking into consideration patient-specific factors and severity of illness. Future pharmacokinetic research correlating plasma and intracellular concentrations of NRTIs during CVVH is warranted to elucidate appropriate dosing.

Removal of Dolutegravir by Hemodialysis in HIV-Infected Patients with End-Stage Renal Disease

Data on dolutegravir removal by hemodialysis are lacking. To study this, we measured dolutegravir plasma concentrations in samples of blood entering and leaving the dialyzer and of the resulting dialysate from 5 HIV-infected patients with end-stage renal disease. The median dolutegravir hemodialysis extraction ratio was 7%. The dolutegravir concentrations after the dialysis session remained far above the protein-binding-adjusted inhibitory concentration. Our results show minimal dolutegravir removal by hemodialysis, with no specific dolutegravir dosage adjustments required in this setting. (This study is registered at ClinicalTrials.gov under registration number NCT02487706.).

HIV-associated nephropathies: epidemiology, pathology, mechanisms and treatment

HIV is a highly adaptive, rapidly evolving virus, which is associated with renal diseases including collapsing glomerulopathy-the classic histomorphological form of HIV-associated nephropathy. Other nephropathies related to viral factors include HIV-immune-complex kidney disease and thrombotic microangiopathy. The distribution of HIV-associated kidney diseases has changed over time and continues to vary across geographic regions worldwide. The reasons for this diversity are complex and include a critical role of APOL1 variants and possibly other genetic factors, disparities in access to effective antiviral therapies, and likely other factors that we do not yet fully understand. The mechanisms responsible for HIVAN, including HIV infection of podocytes and tubular epithelial cells, the molecules responsible for HIV entry, and diverse mechanisms of cell injury, have been the focus of much study. Although combined antiretroviral therapy is effective at preventing and reversing HIVAN, focal segmental glomerulosclerosis, arterionephrosclerosis and diabetic nephropathy are increasingly common in individuals who have received such therapy for many years. These diseases are associated with metabolic syndrome, obesity and premature ageing. Future directions for HIV-related kidney disease will involve regular screening for drug nephrotoxicity and incipient renal disease, as well as further research into the mechanisms by which chronic inflammation can lead to glomerular disease.

Renal insufficiency has no effect on the pharmacokinetics of vicriviroc in a ritonavir-containing regimen

BACKGROUND AND OBJECTIVE

Vicriviroc is a small-molecule CCR5 antagonist currently in development for the treatment of HIV in patients on a regimen containing a ritonavir-boosted protease inhibitor. As renal disease and renal dysfunction are prevalent in the HIV-infected population, patients with varying degrees of renal insufficiency may receive vicriviroc, which is metabolized by cytochrome P450 (CYP) 3A4. The present study therefore examined the impact of renal insufficiency on the pharmacokinetics and safety of vicriviroc alone and in the presence of ritonavir, a strong CYP3A4 inhibitor.

SUBJECTS AND METHODS

This study was an open-label, randomized, two-treatment crossover trial conducted in HIV-negative subjects with haemodialysis-dependent end-stage renal disease (ESRD) and healthy subjects with normal renal function matched by age, height, bodyweight and sex. Subjects received a single dose of vicriviroc 75 mg alone in one period, and in another period they received a single dose of vicriviroc 15 mg after 4 days of ritonavir 100 mg once daily. Ritonavir treatment was then continued for an additional 13 days. The two trial periods were separated by an interval of at least 3 weeks. The primary endpoints were the log-transformed area under the plasma concentration-time curve (AUC) and the maximum plasma concentration (C(max)), and the 90% confidence intervals (CIs) of the mean differences between subjects with ESRD and matched healthy subjects. The protocol provided the option of dose modification and further study if the vicriviroc C(max) and AUC values were at least twice as high in subjects with ESRD compared with healthy subjects, or if warranted by other safety and tolerability observations.

RESULTS

Twelve subjects (six with ESRD, six healthy) completed the study. When vicriviroc was administered alone, the mean vicriviroc C(max) and AUC ratio estimates (90% CI) for subjects with ESRD versus healthy subjects were 74% (53, 103) and 84% (49, 145), respectively. When ritonavir was added to the regimen, the ratio estimates (90% CI) were 81% (59, 111) and 134% (105, 171), respectively. Ritonavir plasma concentrations were substantially higher in subjects with ESRD than in healthy subjects. Treatment-emergent adverse events considered possibly or probably related to treatment occurred only during the ritonavir period of the study and in one healthy subject and two subjects with ESRD; all were of mild or moderate severity.

CONCLUSIONS

ESRD had no clinically relevant impact on exposure of vicriviroc when vicriviroc was administered alone or in the presence of ritonavir. In this single-dose study, vicriviroc was well tolerated both by healthy subjects and by those with ESRD. Dose adjustment of vicriviroc is therefore not necessary in renally impaired populations.

[Diagnosis, treatment and prevention of renal diseases in HIV infected patients. Recommendations of the Spanish AIDS Study Group/National AIDS Plan]

The incidence of opportunistic infections and tumours in HIV-infected patients has sharply declined in the HAART era. At the same time there has been a growing increase of other diseases not directly linked to immunodeficiency. Renal diseases are an increasing cause of morbidity and mortality among HIV-infected patients. In the general population, chronic renal failure has considerable multiorgan repercussions that have particular implications in patients with HIV infection. The detection of occult or subclinical chronic kidney disease is crucial since effective measures for delaying progression exist. Furthermore, the deterioration in glomerular filtration should prompt clinicians to adjust doses of some antiretroviral agents and other drugs used for treating associated comorbidities. Suppression of viral replication, strict control of blood pressure, dyslipidemia and diabetes mellitus, and avoidance of nephrotoxic drugs in certain patients are fundamental components of programs aimed to prevent renal damage and delaying progression of chronic kidney disease in patients with HIV. Renal transplantation and dialysis have also special implications in HIV-infected patients. In this article, we summarise the updated clinical practice guidelines for the evaluation, management and prevention of renal diseases in HIV-infected patients from a panel of experts in HIV and nephrologists on behalf of the Spanish AIDS Study Group (GESIDA) and the National AIDS Plan.

HIV and kidney disease in sub-Saharan Africa

A wide clinical spectrum of renal diseases affects individuals with HIV. These conditions include acute kidney injury, electrolyte and acid-base disturbances, HIV-associated glomerular disease, acute-on-chronic renal disease and adverse side effects related to treatment of HIV. Studies employing varying criteria for diagnosis of kidney disease have reported a variable prevalence of these diseases in patients with HIV in sub-Saharan Africa: 6% in South Africa, 38% in Nigeria, 26% in Côte d'Ivoire, 28% in Tanzania, 25% in Kenya, 20-48.5% in Uganda and 33.5% in Zambia. Results from these studies also suggest that a broader spectrum of histopathological lesions in HIV-associated kidney disease exists in African populations than previously thought. Strategies to prevent or retard progression to end-stage renal disease of HIV-associated kidney conditions should include urinalysis and measurement of kidney function of all people with HIV at presentation. Renal replacement in the form of dialysis and transplantation should be implemented as appropriate. This Review focuses on the available evidence of renal diseases in patients with HIV infection in sub-Saharan Africa and offers practical guidelines to treat these conditions that also take into consideration challenges and obstacles that are specific to sub-Saharan Africa.

The pharmacokinetics and pharmacogenomics of efavirenz and lopinavir/ritonavir in HIV-infected persons requiring hemodialysis

OBJECTIVE

To evaluate the pharmacokinetics and pharmacogenomics of efavirenz (EFV) and lopinavir/ritonavir (LPV/RTV) in HIV-infected persons requiring hemodialysis.

DESIGN

Prospective, observational study of HIV-infected hemodialysis patients receiving one 600 mg tablet daily of EFV (N = 13) or three 133.3/33.3 mg capsules twice daily of LPV/RTV (N = 13).

METHODS

Twenty-four-hour EFV and 12-h LPV/RTV pharmacokinetics were assessed. Geometric mean ratios were calculated using historical controls with normal renal function. The effects of several candidate gene polymorphisms were also explored.

RESULTS

The geometric mean [95% confidence interval (CI); percentage of coefficient of variation (% CV)] Cmin, Cmax, and area under the curve (AUC) for the EFV group were 1.81 microg/ml (0.93, 3.53; 103%), 5.04 microg/ml (3.48, 7.29; 72%), and 71.5 microg h/ml (43.2, 118.3; 93%), respectively. These parameters were 2.76 microg/ml (1.86, 4.11; 53%), 8.45 microg/ml (6.41, 11.15; 52%), and 69.6 microg h/ml (55.6, 87.2; 37%) for LPV and 0.08 microg/ml (0.05, 0.14; 63%), 0.58 microg/ml (0.44, 0.76; 41%), and 3.74 microg h/ml (2.91, 4.80; 37%) for RTV. The AUC geometric mean ratios (90% CI) for EFV, LPV, and RTV were 132% (89, 197), 81% (67, 97), and 92% (76, 111), respectively. LPV Cmin was lower than expected in the hemodialysis group. Higher EFV concentrations were associated with the CYP2B6 516G>T polymorphism.

CONCLUSION

The pharmacokinetics of EFV and LPV/RTV in hemodialysis suggests that no dosing adjustments are necessary in treatment-naive patients. As HIV-infected hemodialysis patients are disproportionately black, the increased frequency of the CYP2B6 516G>T polymorphism may lead to higher EFV levels. The potentially lower LPV trough levels in this population suggest that LPV/RTV should be used with caution in protease-inhibitor-experienced patients.

HIV-1 infection and the kidney: an evolving challenge in HIV medicine

With the advent of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections has declined substantially, and cardiovascular, liver, and renal diseases have emerged as major causes of morbidity and mortality in individuals with human immunodeficiency virus (HIV). Acute renal failure is common in HIV-infected patients and is associated with acute infection and medication-related nephrotoxicity. HIV-associated nephropathy is the most common cause of chronic kidney disease in HIV-positive African American populations and may respond to HAART. Other important HIV-associated renal diseases include HIV immune complex kidney diseases and thrombotic microangiopathy. The increasing importance of non-HIV-associated diseases, such as diabetes mellitus, hypertension, and vascular disease, to the burden of chronic kidney disease has been recognized, focusing attention on prevention and control of these diseases in HIV-positive individuals. HIV-positive individuals who experience progression to end-stage renal disease and who have undetectable HIV-1 viral loads while receiving HAART should be evaluated for renal transplant. Emerging evidence suggests that HIV-positive individuals may have graft and patient survival comparable to HIV-negative individuals. Several studies suggest that HIV-1 can potentially infect renal cells, and HIV transgenic mice have clarified the roles of a number of HIV proteins in the pathogenesis of HIV-associated renal disease. Host factors may modify disease expression at the level of cytokine networks and the renal microvasculature and contribute to the pathogenic effects of HIV-1 infection on the kidney.

Antiretroviral drug dosing errors in HIV-infected patients undergoing hemodialysis

BACKGROUND

Several studies have revealed the frequency of antiretroviral (ARV) drug prescription errors. We analyzed highly active antiretroviral therapy (HAART) prescribing practices for human immunodeficiency virus (HIV)-infected patients undergoing hemodialysis in France.

METHODS

Prescribed ARV drug doses in our cohort (consisting of all HIV-infected patients who underwent hemodialysis from 1 January 2002 and were prospectively followed up until 1 January 2004) were compared with the recommended doses for patients undergoing hemodialysis. The log-rank test was used to compare the outcomes among different groups of treated patients.

RESULTS

One hundred seven of the 129 patients in our cohort received a total of 317 ARV drugs, 59% of which were improperly prescribed. The dosing was too low for 18% of the patients and too high for 39% of the patients. Twenty-eight patients (26%) did not receive any of their ARV drugs at the recommended dose. The lowest prescribed dose (8% of the daily recommended dose) was observed with indinavir and zidovudine, and the highest prescribed dose (1000% of the recommended dose) was observed with stavudine. Among patients who received HAART, those who were prescribed an insufficient dose of a protease inhibitor had more-severe HIV disease and worse 2-year survival than did the other patients (mean rate of survival+/-standard deviation, 79.5%+/-7.5% vs. 95.4%+/-2.6%, respectively; P<.02). For dialyzable ARV drugs, the delay between ARV drug receipt by the patients and dialysis sessions was not respected in 9% of cases, and in 73% of cases, it was not known whether the patients took the ARV drugs before or after dialysis sessions.

CONCLUSION

This is, to our knowledge, the first study to show a significant association between ARV drug prescription errors and survival in patients undergoing dialysis.

Pharmacotherapy for human immunodeficiency virus-associated nephropathy

Approximately 10% of adult patients with human immunodeficiency virus (HIV) infection have HIV-associated nephropathy (HIVAN). This condition, a leading cause of renal failure, is characterized by damage to specific areas of the renal filtration system. It manifests with increased serum creatinine levels, overt proteinuria, and in some patients, end-stage renal disease (ESRD). The mortality rate for HIVAN-related ESRD is high-30% within the first year of onset. Most instances of HIVAN occur in patients of African descent. Although advances in defining the pathology have been made, the optimal treatment strategy remains unclear. Potential benefits of potent combination antiretroviral therapy, angiotensin-converting enzyme (ACE) inhibitors, and corticosteroids have been reported in small clinical trials and case reports. Cyclosporine is another option, but clinical experience with this agent in managing HIVAN is limited. Few conclusions can be drawn from the limited body of available evidence. Antiretroviral therapy, ACE inhibitors, and corticosteroids are possibly associated with reversal of serum creatinine level increases and proteinuria, but studies are necessary to further define the role of these agents in therapy. Close monitoring is advised when treating any patient with HIVAN.

Hepatitis B virus infection in dialysis patients

Hepatitis B virus (HBV) infection remains a major issue among dialysis patients. It is associated with a high risk of hepatic complication. The liver disease runs a unique clinical course in dialysis patients, as it can progress with modest hepatic inflammation and prominent fibrosis. The conventional cut-off level of serum alanine aminotransferase (ALT) for commencing antiviral therapy may prove too high and inappropriate for dialysis patients, and liver biopsy appears to be the only definitive means to establish the activity of liver disease in dialysis patients. Liver biopsy should be considered in patients with a serum ALT level that is persistently greater than 30 IU/L, or 0.75-fold the upper limit of the normal level, and/or other clinical and laboratory findings that suggest active liver disease. For antiviral treatment, preliminary reports have shown that lamivudine is effective and well tolerated in dialysis patients. However, the long-term efficacy of lamivudine and its optimal effective dose in dialysis patients remain unknown. The prevention of nosocomial transmission among dialysis patients is also important. Universal precaution measures should be strictly observed and the segregation of hepatitis B surface antigen-positive hemodialysis patients should be considered. For HBV non-immune patients, the importance of HBV vaccination should not be overemphasized. Until a new generation of highly immunogenic vaccines that are proven to be safe and effective in patients with end-stage renal disease becomes available, early vaccination before the development of end-stage renal failure remains the best way to secure immunological protection against HBV infection in dialysis patients.

Highly active antiretroviral therapy and the kidney: an update on antiretroviral medications for nephrologists

Highly active antiretroviral therapy has dramatically altered the treatment and life expectancy of individuals who are infected with HIV. More than 20 antiretroviral drugs and drug combinations now are available in the United States. Nephrologists need to have an understanding of the pharmacokinetics of antiretroviral medications and the proper dosing of these medications in patients with impaired kidney function. It is also important for nephrologists to be aware of drug-drug interactions that can occur between antiretroviral medications and other medications that they may prescribe, including immunosuppressive medications that are used for renal transplantation, as this becomes more common in HIV-infected patients. Adverse reactions that affect the kidneys and cause fluid-electrolyte complications occur with certain antiretroviral agents, although most are relatively free of nephrotoxicity. This article reviews the clinical pharmacology and dosing modifications of the newer antiretroviral medications in patients with reduced kidney function; important drug-drug interactions involving these medications, particularly with other medications that are likely to be prescribed by nephrologists; and renal toxicities of antiretroviral agents.

Statins' dosage in patients with renal failure and cyclosporine drug-drug interactions in transplant recipient patients

Dyslipidemia is frequent in patients with renal failure and in transplant recipient patients. This lead to a wide use of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) in patients with impaired renal function or in patients treated with cyclosporine as post-transplantation immunosuppressive therapy. As a result, it is crucial for those patients' physicians to be aware of how to handle these drugs when renal function is impaired and/or when cyclosporine is co-administered. Most statins have an extensive hepatic elimination and the renal route is usually a minor elimination pathway. However, pharmacokinetic alterations have been described for some of these drugs in patients with renal insufficiency. Cyclosporine is a widely used immunosuppresive therapy in solid organ transplant patients and drug-drug interactions are likely to occur when statins and cyclosporine are administered together. Those interactions may theoretically result in increased statins and/or cyclosporine serum levels with potential muscle and/or renal toxicity. As a result, caution is warranted if concurrent administration is performed. In this review, we synthesized the data from the literature on (1) the pharmacokinetics and dosage adjustment of atorvastatin, fluvastatin, pravastatin, rosuvastatin, and simvastatin in patients with renal failure and (2) the potential drug-drug interactions between these drugs and cyclosporine in transplant recipient patients.

FHD: an index to evaluate drug elimination by hemodialysis

BACKGROUND

In hemodialyzed patients, physicians have to (1) adjust drug dosage for a creatinine clearance lower than 10-15 ml/min and (2) know whether or not the drug will be removed by the dialysis session to decide whether it may be administered before or after the session on dialysis days. However, of several indices being used to evaluate drug removal by dialysis none is appropriate and we suggest a novel index named F(HD), which reflects the role of hemodialysis clearance of a drug in its overall clearance during the session.

METHODS

Pharmacokinetic simulations were performed to test the influence of dialysis on the pharmacokinetics of some drugs, whether F(HD) was considered or not, to determine when to administer the drug. F(HD) was then calculated for several drugs and its value compared with other indices. Five hemodialysis patients from our department for whom the time of drug administration was determined according to F(HD) were included in a small study and their drugs' trough concentrations were monitored.

RESULTS

F(HD) emphasized that considering hemodialysis clearance alone may lead to false interpretations of the potential dialyzability of some drugs. In our patients, who received their treatment according to the 'F(HD) rule', monitoring of trough levels gave satisfactory results.

CONCLUSION

The use of the 'F(HD) rule' should be tested on a long-term administration basis to confirm our conclusion. F(HD )could be the index of choice to determine when to administer a drug, before or after the session, in hemodialysis patients.

HAART-related nephropathies in HIV-infected patients

There is no doubt that highly active antiretroviral therapy (HAART) has been the most important progress in the therapy of human immunodeficiency virus (HIV)-infected patients in the last decade. A growing number of observations suggest that the beneficial effects of HAART also include improvement of HIV-related renal complications. Consequently, the cohort of HIV-infected patients requiring HAART has increased and includes patients with preexisting nephropathies, whether related or unrelated to HIV infection. However, some antiretroviral drugs may have renal- and life-threatening side-effects, especially if underlying renal abnormalities exist. In this review, we focus on those aspects that require particular attention in preventing new health complications in HIV-infected patients.

Use of highly active antiretroviral therapy in patients with renal insufficiency

Antiretroviral agents, especially nucleoside reverse transcriptase inhibitors, require significant dosage adjustments in patients who have renal dysfunction and the human immunodeficiency virus (HIV). Some antiretroviral agents and fixed combination preparations are contraindicated in this population. In addition, many preferred antiretroviral regimens may be difficult to administer conveniently in patients with decreased creatinine clearance or in those receiving renal replacement therapies. Some highly active antiretroviral therapy regimens, however, can be used conveniently in patients with HIV and altered renal function.

Pharmacokinetic Considerations in the Treatment of Tuberculosis in Patients with Renal Failure

Tuberculosis is re-emerging in patients with altered immune status, such as those with chronic renal failure. Clinicians should thus be aware of the pharmacokinetics and dosage adjustment of antitubercular drugs in patients with renal insufficiency. Among patients with renal insufficiency, those who are dialysed should be treated with special care. Indeed, dosage should always be closely adjusted in these patients and potential removal by dialysis must be taken into account. However reliable the dosage adjustment recommendations are for these drugs in patients with renal failure, further pharmacokinetic investigations need to be performed, especially in dialysis patients in whom the influence of haemodialysis and continuous ambulatory peritoneal dialysis on drug pharmacokinetics needs to be detailed. In the meantime, it could be generally advised to administer all antitubercular drugs after the haemodialysis session, even though some drugs are known to be non-dialysable.

Dialyzing a patient with human immunodeficiency virus infection: what a nephrologist needs to know

The percentage of dialysis centers that have reported dialyzing human immunodeficiency virus (HIV)-infected patients increased from 11% in 1985 to 37% in 2000. Being primary care physicians for the dialysis patients, nephrologists are frequently confronted with the management of HIV-infected dialysis patients especially in urban centers. The aims of the present review are to discuss issues that are unique to HIV infection and end-stage renal disease, and to provide dialysis caretakers with sufficient information to help them optimize care and improve outcomes of these patients. Issues related to the choice of renal replacement therapy, vascular access, management of anemia, vaccination, and antiretroviral therapies are discussed in detail.

Changing trends in the survival of dialysis patients with human immunodeficiency virus in the United States

HIV-infected patients with end-stage renal disease have a very high morbidity and mortality. In the last decade, survival of HIV-infected patients in the United States has remarkably improved. To determine whether similar improvement in survival has occurred in HIV-infected dialysis patients, their survival was evaluated by using the United States Renal Data System database. Survival of HIV-infected dialysis patients in the United States was determined and the influence of year of initiation of dialysis, and demographic characteristics on the survival were analyzed by the Kaplan-Meier method. The effects of above variables on survival were also examined in a Cox proportional hazards model. Identified were 6166 HIV-infected patients with end-stage renal disease who received dialysis in the United States. Eighty-nine percent of the patients were black, 7.4% white, and 3% other. From 1990 to 1999, 1-yr survival of HIV-infected patients on dialysis improved from 56 to 74%, and the annual death rates declined from 458 deaths to 240 deaths per 1000 patient-years. The hazard ratio declined significantly in patients who initiated dialysis in years 1999-2000 compared with patients who initiated dialysis < or = 1990 (hazard ratio, 0.49; 95% confidence interval, 0. 40 to 0.60). Survival of HIV-infected dialysis patients has remarkably improved in the United States.