First human studies on the safety and antitussive activity of vadocaine hydrochloride.

Vadocaine hydrochloride (2',4'-dimethyl-6'-methoxy-3-(2-methylpiperidyl)propionanilide+ ++ hydrochloride, OR K-242-HCl; INN: vadocaine) is a new anilide derivative which resembles lidocaine in chemical structure. The safety and antitussive effects of this new compound were studied in 6 healthy male volunteers in the first Phase I clinical trial. Vadocaine was administered in single doses of 5, 10, 15, 20, 30 and 50 mg. At these dose levels vadocaine had no effects on the cardiovascular system, the haematological variables, blood biochemistry or urinary sediment examined as safety evaluation. The antitussive properties of the compound were studied using inhaled citric acid for induction of the cough response. The antitussive properties of vadocaine were most effective at a dose of 15 mg, although no statistical significance was found. Neither was any dose-response relationship noted. However, at this dose level vadocaine is apparently safe and its antitussive properties seem promising enough for further evaluation.