Effect of indinavir on the single-dose pharmacokinetics of theophylline in healthy subjects

The effect of multiple doses of indinavir on the pharmacokinetics of a single dose of theophylline was investigated in 16 healthy male subjects using a randomized, double-blind placebo-controlled, parallel-group study design. On days 1 and 7 all of the subjects received a single oral 250 mg dose of theophylline. From days 2 to 7 the subjects received orally administered 800 mg doses of indinavir or a matched placebo every 8 hours. On day 7, theophylline and indinavir (or a placebo) were coadministered. The geometric mean AUC((0-24h)) of theophylline increased 18% when coadministered with indinavir compared to when theophylline was administered alone. This small increase in AUC((0-24 h)), although considered statistically significant, did not meet the prespecified criterion for clinical significance. The geometric mean C-max of theophylline, when coadministered with indinavir, was within 8% of theophylline when administered alone. The mean t(max) (+/- SD) value for theophylline, when coadministered with indinavir (0.9 +/- 0.5 h), was comparable to that observed for theophylline alone (1.0 +/- 0.5 h). In conclusion, the administration of multiple doses of indinavir followed by a single dose of theophylline did not appear to result in a clinically significant pharmacokinetic interaction for theophylline. (C) 1999 the American College of Clinical Pharmacology.