Overview of the mucosal protective effects of misoprostol in man.

Misoprostol, a novel synthetic analog of prostaglandin E1 has been evaluated for its potential mucosal protective properties in healthy human subjects using randomized, double-blind, placebo-controlled studies. Misoprostol significantly reduced established aspirin-induced gastric microbleeding. Likewise, misoprostol significantly inhibited aspirin-induced fecal blood loss when administered concurrently with aspirin. The reduction of gastrointestinal blood loss was neither a consequence of the inhibition of gastric secretion, nor a change in aspirin absorption. In addition, misoprostol effectively attenuated the transmucosal potential difference drop induced by sodium taurocholate. In endoscopic studies, misoprostol significantly inhibited damage to the gastroduodenal mucosa induced by aspirin, tolmetin and ethanol. In the ethanol study, the protective effects of misoprostol were significantly and profoundly greater than that afforded by cimetidine administered at an effective gastric antisecretory dose. These studies indicate that misoprostol has mucosal protective property in man. The basis for this mucosal protective effect is not fully known, but laboratory and clinical evidence indicate a direct effect on the barrier functions of the stomach, an increased or maintenance of gastric mucosal blood flow and an enhanced mucus and bicarbonate secretion. The implications of these findings suggest that misoprostol may be useful in the prevention and treatment of acute gastroduodenal mucosal lesions and inflammation.