CYP2B6 genotype-based efavirenz dose recommendations during rifampicin-based antituberculosis cotreatment for a sub-Saharan Africa population.

Aim: To assess genotype effect on efavirenz (EFV) pharmacokinetics, treatment outcomes and provide genotype-based EFV doses recommendations during for tuberculosis (TB)-HIV-1 cotreatment.

Materials & Methods: EFV concentrations from 158 HIV-TB co-infected patients treated with EFV/lamivudine/zidovidine and rifampicin were analyzed. Genotype and CD4 and viral load data were analyzed using a population PK model.

Results: Simulated AUCs for 600 mg EFV dose were 1.2- and 2.4-times greater than the product label for Ugandans in general and CYP2B6*6/*6 genotypes respectively. EFV daily doses of 450 and 250 mg for Ugandans and CYP2B6*6/*6 genotypes, respectively, yielded simulated exposures comparable to the product label.

Conclusions: Around 450 and 250 mg daily doses might meet EFV dosing needs of HIV-TB infected Ugandans in general and CYP2B6*6/*6 genotypes, respectively.