Late onset hepatitis and prolonged deterioration in hepatic function associated with nevirapine therapy

Vanishing bile duct syndrome in human immunodeficiency virus: Nevirapine hepatotoxicity revisited

Vanishing bile duct syndrome (VBDS) refers to a group of disorders characterized by prolonged cholestasis as a result of destruction and disappearance of intrahepatic bile ducts. Multiple etiologies have been indentified including infections, neoplastic disorders, autoimmune conditions and drugs. The natural history of this condition is variable and may involve resolution of cholestasis or progression with irreversible damage. VBDS is extremely rare in human immunodeficiency virus (HIV)-infected patients and anti-retroviral therapy has never been implicated as a cause. We encountered a young pregnant female with HIV and VBDS secondary to anti-retroviral therapy. Here, we report her clinical course and outcome.

Role of reactive metabolites in drug-induced hepatotoxicity

Drugs are generally converted to biologically inactive forms and eliminated from the body, principally by hepatic metabolism. However, certain drugs undergo biotransformation to metabolites that can interfere with cellular functions through their intrinsic chemical reactivity towards glutathione, leading to thiol depletion, and functionally critical macromolecules, resulting in reversible modification, irreversible adduct formation, and irreversible loss of activity. There is now a great deal of evidence which shows that reactive metabolites are formed from drugs known to cause hepatotoxicity, such as acetaminophen, tamoxifen, isoniazid, and amodiaquine. The main theme of this article is to review the evidence for chemically reactive metabolites being initiating factors for the multiple downstream biological events culminating in toxicity. The major objectives are to understand those idiosyncratic hepatotoxicities thought to be caused by chemically reactive metabolites and to define the role of toxic metabolites.

The Liver in HIV in Africa

As access to antiretroviral therapy improves across the African continent, liver disease is emerging as an important cause of morbidity and mortality among HIV-infected individuals. Although coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV), along with highly active antiretroviral therapy (HAART)-induced hepatotoxicity appear to be the major causes of liver disease in this population, other diseases endemic to Africa with hepatic manifestations are influenced by HIV infection as well. In this review we present the available data on liver disease in HIV-infected populations in Africa and discuss relevant data from the rest of the world. In addition, we highlight important areas for further study.

Directly Observed Therapy for the Management of HIV-Infected Patients in a Methadone Program

The objective of this prospective, observational clinical study was to evaluate the safety and efficacy of once-daily and twice-daily directly observed therapy (DOT) in human immunodeficiency virus (HIV)-infected patients undergoing methadone treatment. Methadone and highly active antiretroviral therapy (HAART) were dispensed daily as DOT, with patients in the twice-daily HAART group self-administering the second dose. Clinical and laboratory end points were monitored, along with the impact of ongoing cocaine use. We studied 54 patients coinfected with HIV and hepatitis C virus. At baseline, the median virus load was 111,000 copies/mL, and the median CD4+ cell count was 165 cells/mm3. After a median of 24 months, 17 of 29 patients in the once-daily HAART group and 18 of 25 in the twice-daily HAART group had virus loads of <400 copies/mL, regardless of ongoing cocaine use. Thirty-two patients required methadone dose adjustment, which was managed without modification of HAART. Treatment-limiting hepatic toxicity was rare. A DOT program of coadministered methadone and HAART can be implemented with good results, even for patients who continue to use cocaine.

Antiretroviral Therapy-associated Serious and Life-threatening Toxicities

In the late 1980s and early 1990s, when HIV/AIDS had become the leading cause of death in 25- to 44-year-old persons in the United States, it was acceptable to prescribe newer antiretroviral therapy such as zidovudine, which has significant bone marrow toxicities but can potentially improve patient survival. Although current antiretroviral therapy is not likely to eradicate HIV-1 infection, the advances in the use of combination antiretroviral therapy (including protease inhibitors and non-nucleoside reverse transcriptase inhibitors) have dramatically improved the overall survival, immune status, and productivity of HIV-infected individuals in developed countries. Instead of prevention and treatment of HIV-associated complications, many of the patients" clinic visits are focused on finding strategies to manage and prevent antiretroviral therapy-associated complications. Because only a few HIV-infected persons fulfilling stringent inclusion criteria were included in premarketing clinical trials and because the US Food and Drug Administration"s (FDA) accelerated approval process for antiretroviral therapy requires only 24-week safety and efficacy data, newly emerging and previously unrecognized adverse effects of antiretroviral therapy continue to surface when these drugs are administered to a larger patient population for a longer duration. Unfortunately, some of these adverse effects can be unpredictable and serious, and, if not recognized early and managed aggressively, can lead to fatality. This article reviews four of the most serious, life-threatening toxicities associated with antiretroviral therapy.

Nevirapine quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry. Application to bioequivalence study

A rapid, sensitive and specific method to quantify nevirapine in human plasma using dibenzepine as the internal standard (IS) was developed and validated. The method employed a liquid-liquid extraction. The analyte and the IS were chromatographed on a C(18) analytical column, (150 x 4.6 mm i.d. 4 microm) and analyzed by tandem mass spectrometry in the multiple reaction monitoring mode. The method had a chromatographic run time of 5.0 min and a linear calibration curve over the range 10-5000 ng ml(-1) (r(2) > 0.9970). The between-run precision, based on the relative standard deviation for replicate quality controls was 1.3% (30 ng ml(-1)), 2.8% (300 ng ml(-1)) and 3.6% (3000 ng ml(-1)). The between-run accuracy was 4.0, 7.0 and 6.2% for the above-mentioned concentrations, respectively. This method was employed in a bioequivalence study of two nevirapine tablet formulations (Nevirapina from Far-Manguinhos, Brazil, as a test formulation, and Viramune from Boehringer Ingelheim do Brasil Química e Farmacêutica, as a reference formulation) in 25 healthy volunteers of both sexes who received a single 200 mg dose of each formulation. The study was conducted using an open, randomized, two-period crossover design with a 3 week washout interval. The 90% confidence interval (CI) of the individual ratio geometric mean for Nevirapina/Viramune was 96.4-104.5% for AUC((0-last)), 91.4-105.1% for AUC((0-infinity)) and 95.3-111.6% for C(max) (AUC = area under the curve; C(max) = peak plasma concentration). Since both 90% CI for AUC((0-last)) and AUC((0-infinity)) and C(max) were included in the 80-125% interval proposed by the US Food and Drug Administration, Nevirapina was considered bioequivalent to Viramune according to both the rate and extent of absorption.

Prevalence of adverse events associated with potent antiretroviral treatment: Swiss HIV Cohort Study

BACKGROUND

Data on adverse events to antiretroviral treatment have been recorded in clinical trials, post-marketing analyses, and anecdotal reports. Such data might not be an up-to-date or comprehensive assessment of all possible treatment combinations defined as potent antiretroviral treatment.

METHODS

Using a standard clinical and laboratory method, we assessed prevalence of adverse events in 1160 patients who were receiving antiretroviral treatment. We measured the toxic effects associated with the drug regimen (protease inhibitor [PI], non-nucleoside and nucleoside analogue reverse transcriptase inhibitor) and specific compounds using multivariate analyses.

FINDINGS

47% (545 of 1160) of patients presented with clinical and 27% (194 of 712) with laboratory adverse events probably or definitely attributed to antiretroviral treatment. Among these, 9% (47 of 545) and 16% (30 of 194), respectively, were graded as serious or severe. Single-PI and PI-sparing-antiretroviral treatment were associated with a comparable prevalence of adverse events. Compared with single-PI treatment, use of dual-PI-antiretroviral treatment and three-class-antiretroviral treatment was associated with higher prevalence of adverse events (odds ratio [OR] 2.0 [95% CI 1.0-4.0], and 3.9 [1.2-12.9], respectively). Compound specific associations were identified for zidovudine, lamivudine, stavudine, didanosine, abacavir, ritonavir, saquinavir, indinavir, nelfinavir, efavirenz, and nevirapine.

INTERPRETATION

We recorded a high prevalence of toxic effects attributed to antiretroviral treatment for HIV-1. Such data provides a reference for regimen-specific and compound-specific adverse events and could be useful in postmarketing analyses of toxic effects.