Safety and pharmacokinetics of mifentidine after increasing oral doses in healthy subjects.

Eight healthy men were each given single oral doses of mifentidine 20, 40 and 80 mg, a new H2-receptor antagonist, in a four-way, double-blind, placebo-controlled, cross-over, dose-proportionality study. No significant objective or subjective effects were noted. Mifentidine showed unusual pharmacokinetic behaviour, producing a significant secondary peak in the drug concentration profile.