Plasma pharmacokinetics of once- versus twice-daily lamivudine and abacavir: simplification of combination treatment in HIV-1-infected children (PENTA-13).

Background: There are few data on plasma and intracellular pharmacokinetics (PK) of once-daily (q24h) nucleoside analogues in HIV-infected children.

Methods: Children aged 2-13 years receiving combination treatment containing lamivudine (3TC) (4 mg/kg) and/or abacavir (ABC) (8 mg/kg) twice daily (q12h) were included in this single-arm, open-label, crossover study. Intensive plasma PK sampling was performed at steady state, after which children switched to q24h dosing and PK sampling was repeated 4 weeks later.

Plasma levels of zidovudine twice daily compared with three times daily in six HIV-1-infected children.

Objectives: Zidovudine is often administered every 12 h in HIV-infected children, but so far no pharmacokinetic data are available for the administration of this agent every 12 h. We have evaluated the plasma pharmacokinetics of zidovudine administered every 8 h versus every 12 h in HIV-1-infected children.

Methods: In HIV-1-infected children who switched from zidovudine every 8 h to every 12 h, a pharmacokinetic curve was recorded both before and after the switch.