Disposition of Amodiaquine and Desethylamodiaquine in HIV-infected Nigerian Subjects on Nevirapine-containing Antiretroviral Therapy

Objectives: Artesunate plus amodiaquine is used for malaria treatment in regions with overlapping HIV endemicity. Co-administration of artesunate/amodiaquine with antiretroviral therapy (ART) may result in drug-drug interactions, but minimal data exist. This study evaluated the impact of nevirapine-based ART, containing a backbone of zidovudine and lamivudine, on the disposition of amodiaquine and its active metabolite, desethylamodiaquine (DEAQ).

Methods: This was an open-label, parallel-group pharmacokinetic comparison between HIV-infected, adult subjects receiving steady-state nevirapine-based ART (n = 10) and ART-naive subjects (control group, n = 11). All subjects received a loose formulation of artesunate/amodiaquine (200/600 mg) daily for 3 days, with serial pharmacokinetic sampling over 96 h following the final dose of artesunate/amodiaquine. Amodiaquine and DEAQ were quantified using a validated HPLC method with UV detection. Pharmacokinetic parameters were determined using standard non-compartmental methods.

Results: Exposures to both amodiaquine and DEAQ were significantly lower in the nevirapine-based ART group compared with the control group (amodiaquine AUC₀₋₂₄ 145 versus 204 ng·h/mL, P = 0.02; DEAQ AUC₀₋₉₆ 14,571 versus 21,648 ng·h/mL, P < 0.01). The AUCDEAQ/AUC(amodiaquine) ratio was not different between groups (ART group 116 versus control group 102, P = 0.67).

Conclusions: Subjects on nevirapine-based ART had lower exposure to both amodiaquine and DEAQ (28.9% and 32.7%, respectively). Consequently, this may negatively impact the effectiveness of artesunate/amodiaquine in HIV-infected individuals on this ART combination.