Background: In a retrospective study of HIV patients under antiretroviral therapy, we investigated the influence of the MDR1 genotype (C3435T) on plasma levels of lopinavir (LPV) and efavirenz (EFV).
Methods: The MDR1 genotype was analysed from 67 patients who were treated with LPV (n = 32; mean treatment period 53 weeks) and/or EFV (n = 43, mean treatment period 105 weeks) between 1999 and 2003. Plasma levels of LPV (trough levels) and EFV (12-h-levels) were determined every three months. Data were analysed by the Kruskal-Wallis test.
Results: There were no significant differences in the LPV and EFV plasma levels with respect to the MDR1 3435 genotype.
Conclusions: We did not find evidence for an influence of the MDR1 3435 genotype on plasma levels of LPV and EFV.