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Effects of acid-reducing agents on the pharmacokinetics of lopinavir/ritonavir and ritonavir-boosted atazanavir.

Klein CE, Chiu YL, Cai Y, Beck K, King KR, Causemaker SJ, Doan T, Esslinger HU, Podsadecki TJ, Hanna GJ

Department of Clinical Pharmacokinetics and Pharmacodynamics, Abbott Laboratories Department R4PK, Bldg AP13A, 100 Abbott Park, Abbott Park, IL 60064-6140, USA. cheri.klein@abbott.com

A total of 71 HIV-negative healthy adults were randomized to 1 of 6 regimens to receive lopinavir/ritonavir tablets 400/100 mg twice daily (bid) or 800/200 mg once daily (qd) or atazanavir 300 mg + ritonavir 100 mg qd from study days 1 to 15 with a moderate-fat meal. One hour before breakfast, either omeprazole 40 mg qd was administered on study days 11 through 15, or a single dose of ranitidine 150 mg was administered on study day 11. Lopinavir, atazanavir, and ritonavir pharmacokinetics were determined on study days 10, 11, and 15 and compared using point estimates and 90% confidence intervals (CIs). The point estimates for lopinavir Cmax and AUCtau were in the range of 0.92 to 1.08, with 90% CI contained within the range of 0.80 to 1.25 after coadministration of omeprazole or ranitidine. The point estimates for atazanavir Cmax and AUCtau were decreased by 48% to 62% with the upper bound of the 90% CI <or=0.55 after coadministration of omeprazole or ranitidine. The results indicated that lopinavir bioavailability was not affected by the coadministration of omeprazole or ranitidine. In contrast, atazanavir bioavailability was decreased by 48% to 62% when coadministered with ritonavir and either omeprazole or ranitidine.

Published 28 April 2008 in J Clin Pharmacol, 48(5): 553-62.
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