Hepatotoxicity following nevirapine-containing regimens in HIV-1-infected individuals

To determine the incidence of hepatotoxicity and to investigate whether plasma concentrations of nevirapine, in addition to other risk factors, could predict hepatotoxicity during treatment with nevirapine-containing regimens, we conducted a retrospective analysis with data from 174 individuals infected with human immunodeficiency virus-1 (HIV-1). During regular visits to the clinic, blood samples were collected for the determination of nevirapine plasma concentrations and clinical chemistry parameters including liver enzymes (LEs) and total bilirubin (TBR). Severe hepatotoxicity was defined as a grade > or =3 elevation in at least one of the tested LEs or TBR levels while on therapy. Analysis of predictive factors was focused on increases in aspartate aminotransferase (ASAT) and/or alanine aminotransferase (ALAT) to grade > or =2. Grade > or =3 elevation developed with an incidence of 0.15 per patient year (PY); only 3.4% of the patients developed grade > or =3 values for ASAT and/or ALAT (incidence 0.03 per PY). We found that patients who use a protease inhibitor (PI) in a nevirapine-containing regimen and patients who have chronic hepatitis B (HBV) infection are at a higher risk for the development of increases in ASAT and/or ALAT to grade > or =2. In contrast, the plasma concentration of nevirapine does not appear to be a predictive factor in this study populatio

The steady-state pharmacokinetics of nevirapine during once daily and twice daily dosing in HIV-1-infected individuals

Objective: To investigate and to compare the steady-state plasma pharmacokinetics of nevirapine in a dosing regimen of 400 mg once daily versus 200 mg twice daily in HIV-1-infected individuals. Design: Open-label, randomized, cross-over study. Methods: Twenty HIV-1-infected individuals who already used nevirapine as part of their antiretroviral regimen were randomized to continue their current regimen (200 mg twice daily) or to switch to the alternate regimen (400 mg once daily). The steady-state plasma pharmacokinetics of nevirapine were assessed after 2 weeks during a 24-h period. Subsequently, patients were switched to the alternate regimen and the pharmacokinetics of nevirapine were assessed again after 2 weeks. Noncompartmental methods were used to calculate the area under the plasma concentration versus time curve (AUC([24 h])), and the maximal (C(max)) and minimal plasma concentration (C(min)), the time to C(max) (t(max)), the plasma elimination half-life (t(1/2)), the apparent oral clearance (Cl/F) and the apparent volume of distribution (V/F). Differences in these pharmacokinetic parameters for the two dosing regimens were tested using ANOVA. Results: The exposure to nevirapine, as measured by the AUC([24 h]), was not significantly different between the 400 mg once daily and 200 mg twice daily dosing regimen (P = 0.60). Furthermore, the values for t(max), t(1/2) Cl/F and V/F were not significantly different between the two dosing regimens (P ≥ 0.08). However, C(max) and C(min) were higher and lower, respectively, when nevirapine was used in the once daily regimen as compared with the twice daily regimen. The median values for C(max) and C(min) as measured for the once daily and twice daily regimens were 6.69 and 5.74 μg/ml, respectively (P = 0.03), and 2.88 and 3.73 μg/ml, respectively (P < 0.01). Conclusion: These data show that the daily exposure to nevirapine, as measured by the plasma AUC([24 h]), is not different between a 400 mg once daily and a 200 mg twice daily dosing regimen. However, C(max) and C(min) are higher and lower, respectively, for the once daily regimen as compared with the twice daily regimen. The clinical implications of these differences remain to be established. (C) 2000 Lippincott Williams and Wilkins

Optimizing Antiviral Dosing for HSV and CMV Treatment in Immunocompromised Patients

Herpes simplex virus (HSV) and cytomegalovirus (CMV) are DNA viruses that are common among humans. Severely immunocompromised patients are at increased risk of developing HSV or CMV disease due to a weakened immune system. Antiviral therapy can be challenging because these drugs have a narrow therapeutic window and show significant pharmacokinetic variability. Above that, immunocompromised patients have various comorbidities like impaired renal function and are exposed to polypharmacy. This scoping review discusses the current pharmacokinetic (PK) and pharmacodynamic (PD) knowledge of antiviral drugs for HSV and CMV treatment in immunocompromised patients. HSV and CMV treatment guidelines are discussed, and multiple treatment interventions are proposed: early detection of drug resistance; optimization of dose to target concentration by therapeutic drug monitoring (TDM) of nucleoside analogs; the introduction of new antiviral drugs; alternation between compounds with different toxicity profiles; and combinations of synergistic antiviral drugs. This research will also serve as guidance for future research, which should focus on prospective evaluation of the benefit of each of these interventions in randomized controlled trials

Optimizing Antiviral Dosing for HSV and CMV Treatment in Immunocompromised Patients

Herpes simplex virus (HSV) and cytomegalovirus (CMV) are DNA viruses that are common among humans. Severely immunocompromised patients are at increased risk of developing HSV or CMV disease due to a weakened immune system. Antiviral therapy can be challenging because these drugs have a narrow therapeutic window and show significant pharmacokinetic variability. Above that, immunocompromised patients have various comorbidities like impaired renal function and are exposed to polypharmacy. This scoping review discusses the current pharmacokinetic (PK) and pharmacodynamic (PD) knowledge of antiviral drugs for HSV and CMV treatment in immunocompromised patients. HSV and CMV treatment guidelines are discussed, and multiple treatment interventions are proposed: early detection of drug resistance; optimization of dose to target concentration by therapeutic drug monitoring (TDM) of nucleoside analogs; the introduction of new antiviral drugs; alternation between compounds with different toxicity profiles; and combinations of synergistic antiviral drugs. This research will also serve as guidance for future research, which should focus on prospective evaluation of the benefit of each of these interventions in randomized controlled trials