Acyclovir achieves a lower concentration in African HIV-seronegative, herpes simplex virus 2-seropositive women than in non-African populations.

Acyclovir pharmacokinetics was evaluated in 68 HIV-seronegative, herpes simplex virus 2 (HSV-2)-seropositive African women, who received a single oral 400-mg dose of acyclovir, with plasma acyclovir concentrations measured over 8 h. Geometric mean peak concentration and area under the concentration-time curve were 0.31 μg/ml and 1.59 h · μg/ml, respectively, 54% and 52% lower than values from non-Africans. Lower acyclovir concentrations may partly explain the reduced acyclovir suppression of HSV-2 genital ulcer recurrence in HPTN 039 African women participants.