Twenty-six healthy males took part in this double-blind, randomised, placebo-controlled, two-period, cross-over study. Pantoprazole (40 mg) (test) or placebo (reference) were administered once daily, for 8 days, with a 3 week washout period. A single oral dose of 25 mg warfarin sodium was co-administered with pantoprazole or placebo on Day 2 of each treatment period. The 90% confidence intervals for the 'test/reference' mean ratios of the excess AUC(0.168 h) of prothrombin time and AUC(0.168 h) of factor VII, and of Cmax, AUC and t1/2 of both R- and S-warfarin fell within the equivalence range of 80% to 125%. These results suggest that pantoprazole does not alter the pharmacokinetics or pharmacodynamics of warfarin.