The plasma pharmacokinetics of pantoprazole have been investigated following single intravenous infusion and single oral administration at a dose of 40 mg to 12 healthy male subjects in a randomised cross-over study. Both treatments were generally well tolerated and no relevant compound-related adverse events were noted. The plasma pharmacokinetics of pantoprazole following intravenous infusion in this group of subjects were characterised by a total plasma clearance of 0.13 l.h-1 x kg-1 and apparent terminal elimination half-life 1.9 h. The apparent volume of distribution estimated at steady state (0.17 l.kg-1) was compatible with the localization of a major fraction of the compound in extracellular water. Following oral administration as an enteric-coated tablet formulation, a variable onset of absorption was followed by rapid attainment of maximum plasma concentrations of pantoprazole. Pantoprazole was well absorbed following oral administration; the absolute systemic bioavailability of the compound was estimated as 77% (95% CI, 67 to 89%).