649: Impact of hepatitis C virus infection on buprenorphine dose in pregnancy

Abstract

Buprenorphine (BUP) is the preferred medication for opioid maintenance therapy in pregnancy and is primarily metabolized in the liver. Given that hepatitis C virus (HCV) infection is common in opiate dependent individuals, we sought to determine whether liver dysfunction related to HCV infection impacts the dose of BUP needed during pregnancy. A retrospective cohort study of 266 pregnancies with antenatal exposure to BUP from 2015-2018 at a single center. Individuals positive for HCV infection versus women negative for HCV infection were compared. For HCV prevalence, Kruskal-Wallis tests were performed with continuous variable and Chi-Square tests with categorical variables. Spearman correlation tests were used to assess the relationship between BUP dose and HCV status. In patients with antenatal exposure to BUP, the average age was 29 (18-42) years and 99% were Caucasian. HCV infection was present in 39% of the population. Patients with HCV infection required less dose increases throughout pregnancy (p=0.02). Among the HCV positive cohort, a positive correlation was seen between HCV viral load and the liver enzymes AST (0.30, p=0.003) and ALT (0.25, p=0.01). A negative correlation was noted among the HCV positive cohort for HCV viral load in relation to BUP dose during the second trimester (-0.27, p=0.01) and third trimester (-0.20, p=0.04). HCV infection was associated with less of an increase in BUP dose throughout pregnancy compared to mothers without HCV infection. Among HCV positive mothers, a higher HCV viral load was correlated with higher liver enzymes as well as lower BUP doses during the second and third trimester. These findings may be due to HCV related liver inflammation that potentially decreases liver clearance of BUP. Larger prospective studies as well as pharmacokinetic studies will be useful in further delineating this relationship.