Administration of indinavir and low-dose ritonavir (800/100 mg twice daily) with food reduces nephrotoxic peak plasma levels of indinavir

Abstract

Background: The objective of this study was to compare indinavir peak plasma (Cmax) values after administration of indinavir/ritonavir 800/100 mg on an empty stomach or with food. High indinavir Cmax values have been associated with indinavir-related nephrotoxicity. Methods: This was an open-label, randomized, two-treatment, two-period, cross-over pharmacokinetic study performed at steady state. HIV-infected patients who had been using indinavir/ritonavir 800/100 mg twice daily for at least 4 weeks were randomized to take this combination with a light breakfast (two filled rolls and 130 ml of fluid) on a first study day, and without food on a second day, or in the reverse order. The pharmacokinetics of indinavir and ritonavir were assessed after plasma and urine sampling during 12 h. Results: Data for nine patients were evaluated. Administration of indinavir/ritonavir 800/100 mg on an empty stomach resulted in a higher indinavir Cmax [geometric mean (GM) ratio - fasting/fed and 95% confidence interval (CI): 1.28 (1.08-1.52), P=0.01] and a trend to a shorter indinavir tmax (P=1.07) compared to administration with food. The mode of administration of indinavir/ritonavir did not affect plasma indinavir Cmin and AUC values, parameters that have been associated with the antiviral efficacy of indinavir, nor the urinary excretion of indinavir. Conclusions: Administration of indinavir/ritonavir 800/100 mg on an empty stomach results in a higher indinavir Cmax compared to ingestion with a light meal. Stated the other way round, intake with a light meal reduces indinavir Cmax, which probably reflects a food-induced delay in the absorption of indinavir. It is recommended to administer indinavir/ritonavir 800/100 mg with food, as a possible means to prevent indinavir-related nephrotoxicity in patients who start or continue with this regimen.