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Background. To our knowledge, to date, no prospective, randomized, clinical trial has compared standard doses of efavirenz- and nevirapine-based antiretroviral therapy among patients with concurrent human immunodeficiency virus type 1 (HIV-1) infection and tuberculosis (TB) who are receiving rifampicin. Methods. Rifampicin recipients with concurrent HIV-1 infection and TB were randomized to receive antiretroviral therapy that included either efavirenz (600 mg per day) or nevirapine (400 mg per day). Efavirenz and nevirapine concentrations at 12 h after dosing (C12) were monitored at weeks 6 and 12. CD4+ cell counts and HIV-1 RNA levels were assessed every 12 weeks. Results. One hundred forty-two patients were randomized into 2 groups equally. The mean body weight of patients was 53 kg, the mean CD4+ cell count was 65 cells/mm3, and the median HIV-1 RNA level was 5.8 log10 copies/mL. At weeks 6 and 12, the mean C12 of efavirenz (± standard deviation) were 4.27±4.49 and 3.54±3.78 mg/L, respectively, and those for nevirapine were 5.59±3.48 and 5.6±2.65 mg/L, respectively. Interpatient variability in the efavirenz group was 2.3-fold greater than that in the nevirapine group (coefficient of variation, 107% vs. 47%). At week 12, 3.1% of patients in the efavirenz group and 21.3% in the nevirapine group had C12 values that were less than the recommended minimum concentrations (odds ratio, 8.396; 95% confidence interval, 1.808–38.993; P=.002). Intention-to-treat analysis revealed that 73.2% and 71.8% of patients in the efavirenz and nevirapine groups, respectively, achieved HIV-1 RNA levels <50 copies/mL at week 48, with respective mean CD4+ cell counts of 274 and 252 cells/mm3 (P>.05). Multivariate analysis revealed that patients with low C12 values and those with a body weight <55 kg were 3.6 and 2.4 times more likely, respectively, to develop all-cause treatment failure (P<.05). Conclusions. Antiretroviral therapy regimens containing efavirenz (600 mg per day) were less compromised by concomitant use of rifampicin than were those that contained nevirapine (400 mg per day) in patients with concurrent HIV-1 infection and TB. Low drug exposure and low body weight are important predictive factors for treatment failure. Trial registration. ClinicalTrials.gov identifier: NCT00483054.

Background Moringa oleifera Lam., an herb commonly consumed by HIV-infected people on antiretroviral therapy, inhibits cytochrome P450 3A4, 1A2 and 2D6 activity in vitro; and may alter the pharmacokinetics (PK) of antiretroviral drugs metabolized via the same pathways. However, in vitro drug interaction activity may not translate to a clinically significant effect. Therefore, the effect of moringa leaf powder on the PK of nevirapine in HIV-infected people was investigated. Methods Adult patients at steady-state dosing with nevirapine were admitted for 12-h intensive PK sampling following a 21-day herbal medicine washout. Blood sampling was repeated after 14 days of nevirapine and moringa (1.85 g leaf powder/day) co-administration. Nevirapine plasma concentrations were determined by liquid chromatography-tandem mass spectrometry. To assess the effect of moringa on nevirapine PK, the change in nevirapine area under the plasma concentration–time curve (AUC) was determined. The mean difference in pre- and post-moringa nevirapine, maximum concentration (C max ) and concentration at 12 h (C 12h ) were also calculated. The PK parameters were compared by assessing the post/pre geometric mean ratios (GMRs) and associated 90% confidence intervals (CIs). Results Pharmacokinetics analyses were performed on the results from 11 participants for whom complete data were obtained. The post/pre GMRs and associated 90% CIs for nevirapine were 1.07 (1.00–1.14) for the AUC; 1.06 (0.98–1.16) for C max and 1.03 (0.92–1.16) for C 12h . Conclusion Co-administration of Moringa oleifera Lam. leaf powder at the traditional dose did not significantly alter the steady-state PK of nevirapine. Trial registration number NCT01410058 (ClinicalTrials.gov)

BackgroundThe magnitude of infant antiretroviral (ARV) exposure from breast milk is unknown MethodsWe measured concentrations of nevirapine, lamivudine, and zidovudine in serum and whole breast milk from human immunodeficiency virus type 1 (HIV-1)–infected women in Botswana receiving ARV treatment and serum from their uninfected, breast-feeding infants ResultsTwenty mother-infant pairs were enrolled. Maternal serum concentrations of nevirapine were high (median, 9534 ng/mL at a median of 4 h after nevirapine ingestion). Median breast-milk concentrations of nevirapine, lamivudine, and zidovudine were 0.67, 3.34, and 3.21 times, respectively, those in maternal serum. The median infant serum concentration of nevirapine was 971 ng/mL, at least 40 times the 50% inhibitory concentration and similar to peak concentrations after a single 2-mg/kg dose of nevirapine. The median infant serum concentration of lamivudine was 28 ng/mL, and the median infant serum concentration of zidovudine was 123 ng/mL, but infants were also receiving zidovudine prophylaxis ConclusionsHIV-1 inhibitory concentrations of nevirapine are achieved in breast-feeding infants of mothers receiving these ARVs, exposing infants to the potential for beneficial and adverse effects of nevirapine ingestion. Further study is needed to understand the impact of maternal ARV treatment on breast-feeding HIV-1 transmission, infant toxicity, and HIV-1 resistance mutations among infected infants

Objective. Nevirapine is metabolized by cytochrome P450 (CYP) 2B6 and CYP3A4. We characterized relationships between clinical parameters, human genetics, pharmacokinetics, and human immunodeficiency virus type 1 (HIV-1) drug resistance mutations in pregnant women following single-dose intrapartum nevirapine. Methods. In AIDS Clinical Trials Group study A5207, women received nevirapine at onset of labor and were randomly assigned to receive lamivudine/zidovudine, emtricitabine/tenofovir, or lopinavir/ritonavir for 7 or 21 days. Plasma nevirapine level was quantified on postpartum day 1 and on weeks 1, 3, and 5. We assayed 214 polymorphisms in CYP2B6 and other genes and evaluated associations with pharmacokinetic parameters, including elimination constant, time to protein-adjusted 50% inhibitory concentration (IC₅₀), and week 5 nevirapine level below the quantification limit. Results. Among 301 women with evaluable pharmacokinetic and genotype data, lower body mass index and random assignment to receive lopinavir/ritonavir were associated with more rapid nevirapine elimination. Among those of African ancestry, longer time to IC₅₀ was associated with CYP2B6 983T→C (P = .004) but not with CYP2B6 516G→T (P = .8). Among Indians, slower nevirapine elimination was associated with CYP2B6 516G→T (P = .04). Emergent resistance was infrequent and not associated with pharmacokinetics or CYP2B6 genotype. Conclusions. The effects on plasma drug exposure following single-dose nevirapine may be greater for CYP2B6 983T→C than for 516G→T and are less pronounced than at steady state.

Objective The aim was to develop a model to describe the population pharmacokinetics of nevirapine in South African human immunodeficiency virus (HIV)-infected patients who were taking nevirapine-based antiretroviral therapy concomitantly or in the absence of rifampicin-based tuberculosis therapy. Methods Patients were divided into two groups: (1) patients receiving nevirapine-containing antiretroviral regimen (200 mg twice daily) and continuation phase rifampicin-containing tuberculosis therapy ( n  = 27) in whom blood samples were obtained before and not less than 14 days after they completed tuberculosis therapy; (2) patients without tuberculosis who were receiving a nevirapine-containing antiretroviral regimen for at least 3 weeks ( n  = 26). The population pharmacokinetics of nevirapine was described using nonlinear mixed effects modelling with NONMEM software. Based on the developed model, plasma concentration profiles after 300, 400 and 500 mg of nevirapine twice daily were simulated. Results Concomitant administration of rifampicin increased nevirapine oral clearance (CL/F) by 37.4% and reduced the absorption rate constant (k a ) by almost sixfold. Rifampicin reduced the nevirapine average minimum concentration by 39%. Simulated doses of 300 mg twice daily elevated nevirapine concentrations above subtherapeutic levels in most patients, with minimum exposure above the recommended maximum concentration. The area under the concentration–time curve of 12-hydroxynevirapine was not different in the presence of rifampicin. 2-, 3- and 8-Hydroxynevirapine were not detectable (LLOQ = 0.025 mg/L). Conclusion The developed model adequately describes nevirapine population pharmacokinetics in a South African population when taken with/and in the absence of rifampicin treatment. The simulations suggest that an increased dose of 300 mg twice daily would achieve adequate nevirapine concentrations in most patients during rifampicin-containing treatment for tuberculosis.

Background. The optimum strategy for stopping treatment with drugs that have different half-lives in a combination regimen to minimize the risk of selecting drug-resistant viruses remains unknown. We evaluated drug concentrations in plasma, human immunodeficiency virus (HIV) load, and development of drug resistance after a planned treatment interruption of a nonnucleoside reverse-transcriptase inhibitor (NNRTI)–containing regimen in HIV type 1–infected children. Methods. Children with viral loads <50 copies/mL and CD4 cell percentages ⩾30% (for children aged 2–6 years) or CD4 cell percentages ⩾25% and CD4 cell counts ⩾500 cells/µL (for children aged 7–15 years) were randomized to either a planned treatment interruption or to continuous therapy. In the planned treatment interruption arm, either (1) treatment with nevirapine or efavirenz was stopped, and treatment with the remaining drugs was continued for 7–14 days, or (2) nevirapine or efavirenz were replaced by a protease inhibitor, and all drugs were stopped after 7–14 days. Sampling for determination of plasma drug concentrations, measurement of viral load, and drug resistance testing was scheduled at day 0, day 7 (drug concentrations only), day 14, and day 28 after interruption of treatment with an NNRTI. Results. Treatment with an NNRTI was interrupted for 35 children (20 were receiving nevirapine, and 15 were receiving efavirenz). Median time from NNRTI cessation to stopping all drugs was 9 days (range, 6–15 days) for nevirapine and 14 days (range, 6–18 days) for efavirenz. At 7 days, 1 (5%) of 19 and 4 (50%) of 8 children had detectable nevirapine and efavirenz concentrations, respectively; efavirenz remained detectable in 3 (25%) of 12 children at 14 days. At 14 days, viral load was ⩾50 copies/mL in 6 of 16 children interrupting treatment with nevirapine (range, 52–7000 copies/mL) and in 2 of 12 children interrupting treatment with efavirenz (range, 120–1600 copies/mL). No new NNRTI mutations were observed. Conclusions. In children with virological suppression who experienced interruption of treatment with an NNRTI, staggered or replacement stopping strategies for a median of 9 days for nevirapine and 14 days for efavirenz were not associated with the selection of NNRTI resistance mutations.

Generic antiretroviral therapy is the mainstay of HIV treatment in resource-limited settings, yet there is little evidence confirming the bioequivalence of generic and brand name formulations. We compared the steady-state pharmacokinetics of lamivudine, stavudine and nevirapine in HIV-infected subjects who were receiving a generic formulation (Triomune) or the corresponding brand formulations (Epivir, Zerit, and Viramune). An open-label, randomized, crossover study was carried out in 18 HIV-infected Ugandan subjects stabilized on Triomune-40. Subjects received lamivudine (150 mg), stavudine (40 mg), and nevirapine (200 mg) in either the generic or brand formulation twice a day for 30 days, before switching to the other formulation. At the end of each treatment period, blood samples were collected over 12 h for pharmacokinetic analysis. The main outcome measures were the mean AUC(0-12h) and C(max). Bioequivalence was defined as a geometric mean ratio between the generic and brand name within the 90% confidence interval of 0.8-1.25. The geometric mean ratios and the 90% confidence intervals were: stavudine C(max), 1.3 (0.99-1.71) and AUC(0-12h), 1.1 (0.87-1.38); lamivudine C(max), 0.8 (0.63-0.98) and AUC(0-12h), 0.8 (0.65-0.99); and nevirapine C(max), 1.1 (0.95-1.23) and AUC(0-12h), 1.1 (0.95-1.31). The generic formulation was not statistically bioequivalent to the brand formulations during steady state, although exposures were comparable. A mixed random effects model identified about 50% intersubject variability in the pharmacokinetic parameters. These findings provide support for the use of Triomune in resource-limited settings, although identification of the sources of intersubject variability in these populations is critical.

Nevirapine is a potent non-nucleoside inhibitor of HIV-1 reverse transcriptase and is indicated for use in combination with other antiretroviral agents for the treatment of HIV-1 infection. Piperine (1-piperoylpiperidine) is an alkaloid and the main pungency principle in both black and long pepper. There are indications that piperine inhibits, rather than stimulates, drug metabolism in most cases, thus increasing the bioavailability and effect of some drugs. This was a crossover, placebo-controlled pilot study conducted in a total of eight healthy adult males aged 20-40 years. Subjects were randomly assigned to receive piperine 20mg or placebo each morning for 6 days, and on day 7, nevirapine 200mg plus piperine 20mg or nevirapine plus placebo in a crossover fashion. Blood samples were collected from 1 to 144 hours post-dose for pharmacokinetic analysis. Mean maximum plasma concentration (C(max)), area under the plasma concentration-time curve from 0 hours to the last measurable concentration (C(last)) [AUC(t)], AUC extrapolated to infinity (AUC(infinity)) and C(last) values of nevirapine were increased by approximately 120%, 167%, 170% and 146%, respectively, when co-administered with piperine. The treatments were well tolerated, indicating few or no clinical adverse effects. This pilot study provided evidence for enhanced bioavailability of nevirapine when administered with piperine. Further in-depth studies in a large number of patients receiving different dosage regimens are required to confirm these results and further our understanding of a possible clinical advantage arising from the bioenhancement capabilities of piperine in the treatment of HIV infection.

Background: Nevirapine was the first member of the nonnucleoside reverse transcriptase inhibitor class to be approved for the treatment of HIV infection. It binds directly to the allosteric site on the reverse transcriptase and inhibits the activity of both RNA- and DNA-dependent DNA polymerases. Objective: This study compared the pharmacokinetics and relative bioavailability of a test and reference formulation of nevirapine 200-mg tablets after single oral doses in healthy Chinese men to meet regulatory criteria for marketing of the new generic formulation. Methods: This single-dose, randomized-sequence, open-label, 2-way crossover study was conducted at the Nanjing First Hospital of Nanjing Medical University, Nanjing, China. Healthy male Chinese volunteers were randomized in a 1∶1 ratio to receive a single 200-mg (3.2-mg/kg) tablet of the test or reference formulation, followed by a 2-week washout period and administration of the alternate formulation. The study drugs were administered after a 10-hour overnight fast. Concentrations of nevirapine were assayed using an HPLC-UV method. For analysis of nevirapine pharmacokinetic parameters, blood samples were obtained before dosing and at regularly scheduled intervals over 168 hours after administration. The 2 formulations would be assumed to be bioequivalent for regulatory purposes if the 90% CIs for the log-transformed ratios of nevirapine AUC and C max were within the range established by the US Food and Drug Administration (0.80–1.25). Tolerability was evaluated throughout the study based on vital signs, physical examinations, 12-lead ECGs, and subject interviews concerning adverse events (AEs). Results: Twenty Chinese male subjects were enrolled in and completed the study. Their mean age was 23 years (range, 21–25 years), mean weight was 63 kg (range, 56–70 kg), and mean height was 171 cm (range, 166–176 cm). No period or sequence effect was observed. The mean (SD) t ½ was 38.12 (2.23) hours for the test tablet and 36.79 (5.06) hours for the reference tablet; T max was 3.1 (0.7) and 3.0 (0.7) hours, respectively; C max was 2.52 (0.31) and 2.60 (0.48) mg · L −1; AUC 0–168 was 155.66 (22.41) and 150.66 (22.11) mg · h · L −1; and AUC 0–∞ was 163.30 (22.88) and 157.75 (22.87) mg · h · L −1. Mean relative bioavailability was 103.6% (8.6%). The 90% CIs for the log-transformed ratios of C max (93.51–102.13) and AUC 0–168 ( 99.84–106.74) were within the predetermined range for the assumption of bioequivalence. One subject reported mild headache after receiving the test formulation; the relationship of this AE to study drug was considered uncertain. No serious or clinically significant AEs were observed or reported during the study. Conclusions: In this single-dose study in healthy fasted Chinese males, the test tablet met the regulatory criterion for assumption of bioequivalence to the reference tablet. Both formulations were well tolerated in the population studied. SFDA registration no: 2009L04358.

To investigate the drug interaction potential between itraconazole and nevirapine. Our study was conducted in 12 healthy volunteers in two phases. In phase 1 (from days 1-28), all subjects were randomly assigned to a two-way crossover study of a nevirapine regimen (nevirapine 200 mg once daily for 7 days) and an itraconazole regimen (itraconazole 200 mg once daily for 7 days) with a 14-day wash-out period between. Phase 2 (from days 43-49) was performed 14 days after phase 1 ended, and all subjects received a combination regimen (nevirapine 200 mg combined with itraconazole 200 mg once daily for 7 days). Nevirapine pharmacokinetic studies were carried out starting with the seventh dose of nevirapine in the nevirapine regimen (on days 7-10 or 28-31) and the combination regimen (on days 49-52). Itraconazole pharmacokinetic studies were carried out starting with the seventh dose of itraconazole in the itraconazole regimen (on days 7-10 or 28-31) and the combination regimen (on days 49-52). There was no significant difference in nevirapine pharmacokinetic parameters between the nevirapine and combination regimens. Itraconazole plasma concentrations were lower when it was administered in the combination regimen than when it was administered in the itraconazole regimen. The mean C(max), AUC(0-96) and t (1/2) of itraconazole were significantly reduced by 38, 61 and 31%, respectively. Nevirapine had a strong inducing effect on the metabolism of itraconazole, but there was no significant effect of itraconazole on the pharmacokinetics of nevirapine. However, a higher daily dosage of itraconazole might have an inhibitory effect.