PHARMACOKINETICS OF ORAL ZIDOVUDINE (AZIDOTHYMIDINE) IN PATIENTS WITH AIDS WHEN ADMINISTERED WITH AND WITHOUT A HIGH-FAT MEAL

Zidovudine is the only drug currently approved for the treatment of HIV infection. The present recommended doses found to be efficacious in patients with AIDS (200 mg every 4h) achieve serum zidovudine concentrations > 0.267 μg/ml (1 μmol/l). Since patients often take zidovudine with food, we have investigated the effect of a liquid high-fat meal on the rate of absorption of zidovudine and on the peak serum concentration achieved. Eight patients received their usual dose of zidovudine (100 mg or 250 mg), with and without a liquid high-fat meal, on two separate study days, in a randomized crossover fashion. Blood and urine samples were collected over a 4-h period. In the absence of food, zidovudine is rapidly absorbed; the time to reach maximal serum concentration (Tmax) was 0.68 (± 0.25) h and the mean peak serum concentration (Cmax) achieved was 0.49 (± 0.3) μg/ml (dose normalized to 100 mg dose). In the presence of a high-fat meal, Tmax was significantly prolonged [1.95 (± 0.69) h; P < 0.05] and the Cmax reduced [0.245 (± 0.12) μg/ml; P < 0.05]. This demonstrates that to achieve maximal zidovudine serum concentrations, patients should take this medication on an empty stomach.