The effect of food on pharmacokinetics of zalcitabine in HIV-positive patients

Abstract

Purpose: The purpose of this study was to determine the effect of food on the pharmacokinetics of zalcitabine in HIV-positive patients.

Methods: Twenty patients received single oral 1.5 mg doses of zalcitabine with and without a standard breakfast in an open-label, randomized crossover study with at least a one week washout period between treatments. Serial blood and urine samples were collected over 24 hours and assayed for zalcitabine by a modified GC/MS method.

Results: Administration with food delayed and prolonged absorption resulting in a decrease of approximately 39% in maximal plasma concentrations compared to dosing under fasting conditions. Comparison of plasma AUC values indicated a small (14%) reduction in bioavailability when given with food. Approximately 59% and 45% of the dose were excreted unchanged in the urine under fasting and fed conditions, respectively.

Conclusions: The results of this study show that the administration of zalcitabine with food results in a mild reduction in bioavailability. Although these changes are not expected to be of clinical importance, further studies must be conducted for confirmation.