Prospective comparison of patient tolerance to enteric-coated vs nonenteric-coated erythromycin

Erythromycin base and its salts are frequently used in clinical practice. The most frequent side effects of oral erythromycin preparations are gastrointestinal. Various salts and enteric coatings have been developed without adequate comparison in regard to gastrointestinal side effects. The overall incidence of gastrointestinal side effects (abdominal pain and cramps, nausea, vomiting, diarrhea, and gas) of two common erythromycin base formulations, Erythromycin Base Filmtab (Abbott), a nonenteric-coated base tablet, and Eryc (Parke-Davis), a pelletized, encapsulated, enteric-coated base capsule, were compared in 368 adults at two dosage levels (1 g/d and 2 g/d). Minimal differences were found when target symptoms were compared by preparation coating. In contrast, subjects receiving erythromycin at the 2-g/d dosage level reported higher incidence rates for each of the target symptoms, regardless of product coating, than did those patients treated at the 1-g/d dosage level. Enteric coating of erythromycin base offers little protection from the common dose-related gastrointestinal adverse effects of oral erythromycin.