Fendiline was administered intravenously (3 mg) and orally (50 mg and 75 mg) in a cross-over study to six healthy volunteers. The plasma levels of unchanged fendiline and of total radioactivity were measured. Fendiline was absorbed well and its concentration declined biexponentially with mean terminal half-lives of 20-35 h. Since the drug is extensively metabolized, only 12% of total radioactivity in plasma corresponded to fendiline in the case of intravenous administration as compared to less than 2% after oral administration. 56-65% of the administered dose are excreted via the urine and 18-25% with the feces within five days.