Safety of nevirapine in pregnancy

Liver injury associated with drug intake during pregnancy

Drug use during pregnancy is not common. Drug-induced liver injury (DILI) is a potential complication that is rare but can adversely affect both the mother and the fetus. Although many drugs can directly cause hepatotoxicity, idiosyncratic liver injury is common in pregnancy. Underreporting of adverse drug reactions, lack of adequate literature regarding drug safety in pregnancy, and the inherent difficulty in diagnosing DILI during pregnancy make the management of this condition challenging. This review attempts to describe the existing literature regarding DILI in pregnancy, which is mainly in the form of case reports; several studies have looked at the safety of antithyroid drugs, antiretroviral drugs, and paracetamol, which have an indication for use in pregnancy; the relevant data from these studies with regard to DILI has been presented. In addition, the review describes the diagnosis of DILI, grading the disease severity, assessment of causality linking the drug to the adverse event, regulatory guidelines for evaluating the potential of drugs to cause liver injury, efforts to ensure better participation of women in clinical trials and studies in pregnant women population in particular, and the challenges involved in generating adequate research evidence. The establishment of DILI registries in various countries is an encouraging development; however, there is a need for promoting active, spontaneous reporting of adverse events during pregnancy to ensure rapid generation of evidence regarding the safety of a drug in pregnant women.

In vitro assessment of competitive and time-dependent inhibition of the nevirapine metabolism by nortriptyline in rats

Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor of human immunodeficiency virus type 1 (HIV-1) widely used as a component of High Active Antiretroviral Therapy (HAART) since it is inexpensive, readily absorbed after oral administration and non-teratogenic. In the present work, the mechanism of a previously described pharmacokinetic interaction between NVP and the antidepressant drug nortriptyline (NT) was studied using rat hepatic microsomes. The obtained results showed a competitive inhibition of the NVP metabolism by NT. The three main NVP metabolites (2-OH-NVP, 3-OH-NVP and 12-OH-NVP) where competitively inhibited with similar inhibitory constant values (K_i = 4.01, 3.97 and 4.40 μM, respectively). Time-dependent inhibition of the NVP metabolism was also detected, with a 2.5-fold reduction in the IC₅₀ values of NT for 2-, 3-, and 12-OH-NVP formation when NT was preincubated with the microsomal suspension in the presence of an NADPH-generating system. A concentration-dependent inhibition of the formation of NVP metabolites by the main NT metabolite (10-OH-NT) was also observed, however, the inhibitory potency of 10-OH-NT was much lower than that of the parent drug. The apparent hepatic intrinsic clearance of NVP determined in these in vitro experiments was used to predict the in vivo clearance of NVP using the "well-stirred" and the "parallel-tube" models, resulting in values close to those previously observed in vivo clearance. Finally, a good prediction of the increase in the plasma concentrations of NVP when co-administered with NT was obtained employing the inhibitory constant of NT determined in vitro and the estimated plasma concentration of NT entering the liver.

Sex-dependent metabolism of nevirapine in rats: impact on plasma levels, pharmacokinetics and interaction with nortriptyline

Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) widely used in the treatment of human immunodeficiency virus type 1 (HIV-1) and is the first-choice NNRTI during pregnancy. NVP shows a sex dimorphic profile in humans with sex differences in bioavailability, biotransformation and toxicity. In this study, sex differences in NVP metabolism and inhibition of NVP metabolism by the antidepressant nortriptyline (NT) were evaluated using rats as experimental animals. NVP was administered orally to male and female rats and sex differences in plasma levels and pharmacokinetic parameters were analysed. NVP plasma levels were higher in female compared with male rats, and pharmacokinetic parameters such as maximum plasma concentration (C_max), time to C_max (T_max), half-life (t_1/2) and area under the plasma concentration-time curve from the time of dosing to the last measurable concentration (AUC_last) showed ca. 4-, 5-, 7- and 22-fold higher values in female rats. In vitro experiments carried out with hepatic microsomes confirmed slower NVP metabolism in female rats, with a maximum velocity (V_max) 2-fold lower than in male hepatic microsomes. The major metabolite in both sexes was 12-hydroxynevirapine (12-OH-NVP), with the V_max for this metabolite being 15-fold lower in female compared with male rat hepatic microsomes. Inhibition of NVP metabolism by NT was similar in both sexes, with statistically non-significant differences in 50% inhibitory concentration (IC₅₀) values. In summary, NVP is metabolised more slowly in female compared with male rats, but the inhibitory effect of NT is similar in both sexes.

Severe antiretroviral-associated skin reactions in South African patients: a case series and case-control analysis

PURPOSE

Severe skin reactions may complicate combination antiretroviral therapy (cART). Nevirapine is known to be associated with severe skin reactions, but there are conflicting data on risk factors in African patients. We reviewed cases of severe skin reactions admitted to a tertiary hospital in Cape Town, South Africa. We identified associations with severe skin reactions in patients on cART.

METHODS

We described severe skin reaction cases in patients taking cART admitted to Groote Schuur Hospital in Cape Town, South Africa, between 2006 and 2012. We included those patients who developed a severe skin reaction within 120 days of cART initiation in a case-control analysis. We identified control patients matched on date of cART initiation and primary care facility by linkage with the Western Cape electronic provincial HIV database. We conducted a conditional (fixed effects) logistic regression modelling.

RESULTS

We identified 169 severe skin reactions in patients on cART. The most common presentations were Stevens Johnson syndrome/toxic epidermal necrolysis (49%) and drug hypersensitivity syndrome (36%). One hundred forty-one patients were female, of which 27 were pregnant. Median duration of hospitalization was 12 days (interquartile range 8 to 19) and six patients died. We included 91 cases and 361 matched controls in the analysis. Severe skin reaction was associated with nevirapine exposure, adjusted odds ratio of 7.6 (95%CI 3.7 to 15.7) and with pregnancy, adjusted odds ratio 3.7 (95%CI 1.3 to 10.8) compared with men.

CONCLUSIONS

Severe skin reactions resulted in prolonged admission to hospital in this setting. We found that nevirapine use and pregnancy are independently associated with severe skin reaction. Copyright © 2016 John Wiley & Sons, Ltd.

Pregnancy is associated with elevation of liver enzymes in HIV-positive women on antiretroviral therapy

Objective:

The objective of this study is to assess whether pregnancy is associated with an increased risk of liver enzyme elevation (LEE) and severe LEE in HIV-positive women on antiretroviral therapy (ART).

Design:

Two observational studies: the UK Collaborative HIV Cohort (UK CHIC) study and the UK and Ireland National Study of HIV in Pregnancy and Childhood (NSHPC).

Methods:

Combined data from UK CHIC and NSHPC were used to identify factors associated with LEE (grade 1–4) and severe LEE (grade 3–4). Women starting ART in 2000–2012 were included irrespective of pregnancy status. Cox proportional hazards were used to assess fixed and time-dependent covariates including pregnancy status, CD4⁺ cell count, drug regimen and hepatitis B virus/hepatitis C virus (HBV/HCV) coinfection.

Results:

One-quarter (25.7%, 982/3815) of women were pregnant during follow-up, 14.2% (n = 541) when starting ART. The rate of LEE was 14.5/100 person-years in and 6.0/100 person-years outside of pregnancy. The rate of severe LEE was 3.9/100 person-years in and 0.6/100 person-years outside of pregnancy. The risk of LEE and severe LEE was increased during pregnancy [LEE: adjusted hazard ratio (aHR) 1.66 (1.31–2.09); severe LEE: aHR 3.57 (2.30–5.54)], including in secondary analyses excluding 541 women pregnant when starting ART. Other factors associated with LEE and severe LEE included lower CD4⁺ cell count (<250 cells/μl), HBV/HCV coinfection and calendar year.

Conclusion:

Although few women developed severe LEE, this study provides further evidence that pregnancy is associated with an increased risk of LEE and severe LEE, reinforcing the need for regular monitoring of liver biomarkers during pregnancy.

Adverse events associated with nevirapine use in pregnancy: a systematic review and meta-analysis

INTRODUCTION

The risk of adverse drug events associated with nevirapine (NVP) is suggested to be greater in pregnant women. We conducted a systematic review and meta-analysis of severe adverse events in HIV-positive women who initiated NVP while pregnant.

METHODS

We searched six databases for studies reporting adverse events among HIV-positive pregnant women who had received NVP-based antiretroviral therapy for at least 7 days. Data were pooled by the fixed-effects method.

RESULTS

Twenty studies (3582 pregnant women) from 14 countries were included in the final review. The pooled proportion of patients experiencing a severe hepatotoxic event was 3.2% [95% confidence interval (CI) 2.1-4.3%], severe rash was experienced by 3.3% of patients (95% CI 2.1-4.5%) and 6.1% (95% CI 3.9-8.3%) of patients discontinued NVP due to an adverse event. These results were comparable to frequencies observed in the general adult patient population, and to frequencies reported in non-pregnant women within the same cohort. For pregnant women with a CD4 cell count above 250 cells/μl there was a non-significant tendency towards an increased likelihood of severe cutaneous adverse events (OR 1.4, 95% CI 0.8-2.4) and severe hepatotoxic events (OR 1.5, 95%CI 0.9-2.3) and consequently an increased risk of toxicity-driven regimen substitution (OR 1.7, 95% CI 1.1-2.6).

DISCUSSION

These results suggest that the frequency of adverse events associated with NVP use in pregnant women, although high, is no higher than reported for NVP in the general adult population. Pregnant women with a high CD4 cell count may be at increased risk of adverse events, but evidence supporting this association is weak.

Hcv coinfection, an important risk factor for hepatotoxicity in pregnant women starting antiretroviral therapy

OBJECTIVES

This retrospective cohort study evaluated the risk of hepatotoxicity in HIV-1 positive pregnant and non-pregnant women starting combined ART.

METHODS

Data were used from the ATHENA observational cohort. The study population consisted of HIV-1 infected, therapy naïve, pregnant and non-pregnant women, followed between January 1997 and February 2008. Demographic, treatment and pregnancy related data were collected. Risk of hepatotoxicity was determined using univariate and multivariate logistic regression. Analyses were adjusted for age, region of origin, baseline HIV-RNA levels and CD4 cell counts, cART regimen and hepatitis B and C coinfection. ALT and AST values of more than 5 times ULN were considered as hepatotoxicity.

RESULTS

Four-hundred and twenty-five pregnant and 1121 non-pregnant women were included. Independent risk factors of hepatotoxicity in all women were the presence of detectable HCV RNA (OR 5.48, 95% CI 2.25-13.38, p<0.001) and NVP use (OR 2.63, 95% CI 1.54-4.55, p<0.001). Stratified for pregnancy, the adjusted risk of hepatotoxicity was significantly associated with HCV coinfection only during pregnancy (OR 23.53, 95% CI 4.69-118.01, p<0.001). NVP use is related to hepatotoxicity in pregnant (OR 5.26, 95% CI 1.61-16.67, p<0.005) as well as in non-pregnant women (OR 2.13, 95% CI 1.11-4.00, p=0.02).

CONCLUSION

HCV coinfection and NVP use are associated with a higher risk of cART induced hepatotoxicity in pregnant women.

Nevirapine-associated hepatotoxicity and rash among HIV-infected pregnant women in Kenya

BACKGROUND

Few studies have evaluated the risk of nevirapine (NVP)-associated hepatotoxicity among HIV-infected pregnant women with a CD4 count ≥250 cells/mm(3).

METHODS

We enrolled HIV-infected pregnant Kenyan women who initiated triple antiretroviral therapy (ART) at 34 weeks gestation. We compared the rates of severe hepatotoxicity (grades 3-4 hepatotoxicity) and rash-associated hepatotoxicity (rash with ≥grade 2 hepatotoxicity) with NVP and nelfinavir (NFV), respectively.

RESULTS

We initiated triple ART in 522 pregnant women; severe hepatotoxicity and rash-associated hepatotoxicity occurred in 14 (3%) and 9 (2%) women, respectively. Women who initiated NVP had higher rates of severe hepatotoxicity (5% vs 1%; P = .03) and rash-associated hepatotoxicity (4% vs 0%; P = .003) when compared with NFV. Among women who initiated NVP (n = 254), a baseline CD4 count ≥250 cells/mm(3) was not associated with severe hepatotoxicity (5% vs 3%; P = .52) or rash-associated hepatotoxicity (4% vs 3%; P = .69).

CONCLUSION

Nevirapine use but not CD4 count ≥250 cells/mm(3) was associated with hepatotoxicity.

Nevirapine-associated hepatotoxicity was not predicted by CD4 count ≥250 cells/μL among women in Zambia, Thailand and Kenya

OBJECTIVE

The aim of the study was to determine risk factors for developing severe hepatotoxicity (grade 3 or 4 hepatotoxicity) and rash-associated hepatotoxicity (rash with ≥ grade 2 hepatotoxicity) among women initiating nevirapine-based antiretroviral therapy (ART).

METHODS

The Non-Nucleoside Reverse Transcriptase Inhibitor Response Study was a prospective cohort study carried out in Zambia, Thailand and Kenya. Between May 2005 and January 2007, we enrolled antiretroviral-naïve HIV-infected women initiating nevirapine-based ART. At enrollment and at weeks 2, 4, 8, 16 and 24, participants had serum alanine transferase (ALT) and aspartate transaminase (AST) measured and were evaluated clinically for hepatitis and rash.

RESULTS

Nevirapine-based ART was initiated in 820 women and baseline ALT or AST results were abnormal (≥ grade 1) in 113 (14%) women. After initiating nevirapine-based ART, severe hepatotoxicity occurred in 41 (5%) women and rash-associated hepatotoxicity occurred in 27 (3%) women. In a multivariate logistic regression model, severe hepatotoxicity and rash-associated hepatotoxicity were both associated with baseline abnormal (≥ grade 1) ALT or AST results, but not with a baseline CD4 cell count ≥250 cells/μL. Three participants (0.4%) died with symptoms suggestive of fatal hepatotoxicity; all three women had baseline CD4 count <100 cells/μL and were receiving anti-tuberculosis therapy.

CONCLUSION

Among women taking nevirapine-based ART, severe hepatotoxicity and rash-associated hepatotoxicity were predicted by abnormal baseline ALT or AST results, but not by a CD4 count ≥250 cells/μL. In resource-limited settings where transaminase testing is available, testing should focus on early time-points and on women with abnormal baseline ALT or AST results.

Lack of increased hepatotoxicity in HIV-infected pregnant women receiving nevirapine compared with other antiretrovirals

OBJECTIVE

To estimate whether HIV-infected pregnant women were at an increased risk of hepatotoxicity when taking nevirapine (NVP)-containing regimens compared with HIV-infected pregnant women taking antiretroviral therapy (ART) not containing NVP.

METHODS

This analysis included HIV-infected pregnant women on ART from two multicenter, prospective cohorts: the Women and Infants Transmission Study and the International Maternal Pediatric Adolescent AIDS Clinical Trials protocol P1025. Multivariate Cox proportional hazards regression models were used to investigate the association between NVP use and hepatotoxicity. NVP use was dichotomized as use or no use and further categorized according to ART exposure history. We investigated two outcomes: any liver enzyme elevation (LEE) (grade 1-4) and severe LEE (grade 3-4).

RESULTS

A total of 1229 women with ART use during pregnancy were studied, 218 (17.7%) of whom received NVP. Among the women receiving NVP, 137 (62.8%) were NVP naive. Twenty-nine women (13.3%) who received NVP developed any LEE and one (0.5%) developed severe LEE. Of the 1011 women on non-NVP regimens, 145 (14.3%) developed any LEE and 14 (1.4%) developed severe LEE. There were no maternal deaths. In univariate models, LEE was not significantly associated with CD4 cell count above 250 cells/mul or NVP use. In adjusted multivariate models, no significant increased risk of LEE (any or severe) in women taking NVP was detected as compared to those taking other ART regardless of prior exposure history.

CONCLUSION

We did not observe an increased risk of hepatotoxicity among HIV-infected pregnant women on NVP versus other ART, including women who were ART naive.

Antiretroviral treatment during pregnancy

OBJECTIVE

Virologic failure of HIV-positive patients is of special concern during pregnancy. We compared virologic failure and the frequency of treatment changes in pregnant and non-pregnant women of the Swiss HIV Cohort Study.

METHODS

Using data on 372 pregnancies in 324 women we describe antiretroviral therapy during pregnancy. Pregnant women on HAART at conception (n = 131) were matched to 228 non-pregnant women (interindividual comparison) and to a time period of equal length before and after pregnancy (intraindividual comparison). Women starting HAART during pregnancy (n = 145) were compared with 578 non-pregnant women starting HAART.

FINDINGS

The median age at conception was 31 years, 16% (n = 50) were infected through injecting drug use and the median CD4 cell count was 489 cells/microl. In the majority of pregnancies (n = 220, 59%), women had started ART before conception. When ART was started during pregnancy (n = 145, 39%), it was mainly during the second trimester (n = 100, 69%). Two thirds (n = 26) of 35 women starting in the third trimester were diagnosed with HIV during pregnancy. The risk of virologic failure tended to be lower in pregnant than in non-pregnant women [adjusted odds ratio 0.52 (95% confidence interval 0.25-1.09, P = 0.08)], but was similar in the intraindividual comparison (adjusted odds ratio 1.04, 95% confidence interval 0.48-2.28). Women starting HAART during pregnancy changed the treatment less often than non-pregnant women.

CONCLUSION

Despite the physiological changes occurring during pregnancy, HIV infected pregnant women are not at higher risk of virologic failure.

Steady-state nevirapine plasma concentrations are influenced by pregnancy

OBJECTIVES

Optimal plasma concentrations of antiretroviral drugs are required during pregnancy to treat maternal HIV infection and prevent mother-to-child transmission. We investigated the effect of pregnancy on nevirapine (NVP) plasma concentrations.

METHODS

We included all HIV-1-infected women for whom NVP plasma concentrations were available as part of routine patient care at two university hospitals. Plasma NVP concentrations were compared for pregnant (n=45) and non-pregnant (n=152) women. Univariate and multivariate linear regression analyses were used to identify and adjust for other confounding factors associated with NVP plasma concentrations. For pregnant women who had a plasma NVP concentration available both during and outside pregnancy, a paired analysis was performed.

RESULTS

Steady-state NVP plasma concentrations were lower in pregnant women: 5.2 mg/L (interquartile range 3.9-6.8) vs. 5.8 mg/L (4.3-7.7) (P=0.08). After adjusting for confounders, both pregnancy (regression coefficient=-0.90 mg/L, P=0.046) and African descent (regression coefficient=+1.13 mg/L, P=0.005) influenced NVP concentrations significantly. The paired analysis showed mean concentrations of 4.8 mg/L during pregnancy and 5.8 mg/L outside pregnancy (paired t-test, P=0.073).

CONCLUSIONS

Pregnancy has a moderate but significant lowering effect on NVP plasma concentrations. Being of African descent compensates for the lowering effect of pregnancy on NVP concentrations.