THE ENKEPHALINASE INHIBITOR, ACETORPHAN, IN ACUTE DIARRHEA - A DOUBLE-BLIND, CONTROLLED CLINICAL-TRIAL VERSUS LOPERAMIDE

The antidiarrhoeal properties of acetorphan, an inhibitor of enkephali nase (EC 3.4.24.11) that prevents endogenous enkephalin degradation, a nd loperamide, a mu opiate receptor agonist, were compared. The double -blind study included 69 patients with acute diarrhoea of presumed inf ectious origin, allocated at random to two parallel groups. Acetorphan and loperamide were both rapidly and similarly effective, diarrhoea r esolving in both cases in nearly 2 days. With acetorphan, however, abd ominal distension vanished significantly more rapidly, and reactive co nstipation was less frequent (8% versus 31% with loperamide). These di fferences can be accounted for by the distinct mechanisms of antidiarr hoeal activity of the two drugs-that is, primary antitransit effect fo r loperamide and antisecretory activity for acetorphan.