Trough concentrations of lopinavir, nelfinavir, and nevirapine with standard dosing in human immunodeficiency virus-infected pregnant women receiving 3-drug combination regimens

The objective of this study was to evaluate the plasma drug concentrations in human immunodeficiency virus (HIV)infected pregnant women receiving highly active antiretroviral therapy (HAART) and to define the rate of occurrence of subtherapeutic concentrations for some commonly used antiretroviral drugs during pregnancy. We evaluated HIV-infected women (n = 68) in the third trimester of pregnancy in steady-state treatment with an HAART regimen administrated on a twice a day basis, which included 2 nucleoside reverse transcriptase inhibitors plus nelfinavir (NFV), lopinavir/ritonavir (LPV/r), or nevirapine (NVP). Blood samples were collected at predose (C-trough). The following thresholds were used to define therapeutic drug concentrations-NFV: 0.8 mu g/mL; LPV: 4.0 mu g/mL/1.0 mu g/mL (experienced/naive): and NVP: 3.1 mu g/mL. At predose sampling, adequate drug concentrations were found in a higher proportion of women receiving NFV (70.8%) and LPV (75.0%) than NVP (55.6%). Median C-trough plasma concentrations, were 1.2 mu g/mL for NFV, 5.5 mu g/mL for LPV and 3.1 mu g/mL for NVP, Women receiving lopinavir/ritonavir had the lowest rates of detectable (>50 copies/mL) HFV RNA (15.4%) compared with rates of 22.2% and 41.7% among women receiving NVP and NFV, respectively. Genotypic resistance was detected in 50% of women with detectable HIV RNA for whom samples were available for testing. subtherapeutic predose concentrations among HIV-infected pregnant women were more commonly found with NVP than with protease inhibitors. LPV administration was associated with the best viral load suppression.