Best single time point correlations with AUC for cyclosporine and tacrolimus in HIV-infected kidney and liver transplant recipients.

Background: Interactions between antiretrovirals (ARVs) and transplant immunosuppressant agents (IS) among HIV-infected transplant recipients may lead to lack of efficacy or toxicity. In transplant recipients not infected with HIV, tacrolimus (TAC) trough levels (C0) or cyclosporine (CsA) drawn at C0 or 2 hours after dosing (C2) correlate with drug exposure (area under the curve [AUC]/dose) and outcomes. Because of ARV-IS interactions in HIV-infected individuals, and the high rate of rejection in these subjects, this study investigated the correlations between IS concentrations and exposure to determine the best method to monitor immunosuppressant levels.