Blood Levels of Abacavir in HIV Infected Adolescents

Inclusion Criteria: HIV-1 infected CD4 count greater than 100 cells/mm3 Viral load less than 100,000 copies/ml Have taken an abacavir-containing regimen for at least 8 weeks prior to study entry Weight more than 83 lbs (37.5 kg) Ability and willingness to swallow study medications Consent of parent or guardian, if applicable Exclusion Criteria: Any Grade 3 or greater toxicity within 14 days prior to study entry Participation in PACTG P1018 CDC Category C opportunistic infections or HIV-1 associated cancer requiring drug therapy at the time of study enrollment Treatment with immune modulators, including interleukin-2 or intravenous gamma globulin, within 30 days of study entry Received therapeutic vaccines or any HIV-1 vaccine given for primary prevention within 30 days of study entry Surgical or medical problem affecting gastrointestinal motility or absorption (e.g., ileus, ulcerative colitis) or liver function History of chronic alcohol use Any clinically significant disease other than HIV-1 infection that, in the investigator's opinion, would represent an increased risk for the participant or compromise the outcome of the study Chemotherapy for active cancer Pregnancy or breastfeeding