EFFECTS OF 2 ORAL ERYTHROMYCIN ETHYLSUCCINATE FORMULATIONS ON THE MOTILITY OF THE SMALL-INTESTINE IN HUMAN-BEINGS

Fourteen-membered macrolides are known to produce alterations in diges tive tract motor activity; these include the induction of strong gastr ic contractions and a decrease in the motility of the small intestine, The aim of the study was to compare the effects of two different form ulations of erythromycin ethylsuccinate (EE) on duodenojejunal motilit y, Compared with the more commonly used crystalline formulation of EE (GEE), the amorphous formulation (AEE) has previously been described t o have greater bioavailability and to induce significantly fewer gastr ointestinal side effects when given at therapeutic and what have been considered to be equivalent oral doses (i.e., GEE, 1,000 mg every 12 h ; AEE, 500 mg every 12 h). In a crossover double-blind study, duodenoj ejunal manometric recordings were performed for 10 volunteers treated with placebo, CEE at 1,000 mg, or AEE at 500 mg. Recordings for each v olunteer were obtained for a fed period after a standard dinner and th en for a nocturnal fasting period. When compared with the placebo, CEE significantly decreased the motility index of the duodenum during the 30 min after the peak serum erythromycin concentrations, shortened th e duration of the fed state, and had no effect during the fasting stat e, In contrast, AEE did not significantly modify any motility paramete r. Because AEE produced significantly lower concentrations in serum th an GEE, these results do not necessarily imply that the two formulatio ns of EE act differently on the motility of the small intestine.