<p>An interaction study with Tiotroplum (14.4 mcg intravenous infusion over 15 minutes) and cimetidine 400 mg three times daily or ranitidine 300 mg once daily was conducted. Concomitant administration of cimetidine with Tiotroplum resulted in a 20% increase in the AUC 0-4 hour, a 28% decrease in the renal clearance of Tiotroplum and no significant change in the Cmax and amount excreted in urine over 96 hours. Co-administration of Tiotroplum with ranitidine did not affect the pharmacokinetics of Tiotroplum.</p>