Efficacy of prostanoids in the treatment of gastric ulcer.

Prostanoids decrease gastric acid secretion and exert cytoprotective properties. The effect of several synthetic prostanoids on gastric ulcer healing was evaluated. The first trials were performed on a small number of patients with PGE2 analogs and their results were inconclusive. Two huge multicenter trials tested the efficacy of misoprostol, a synthetic PGE1 analog, in comparison to placebo and cimetidine. In the placebo-controlled trial, following 8 weeks of therapy, misoprostol 100 micrograms q.i.d was significantly better than placebo. In the cimetidine controlled trial, 2 doses of misoprostol were tested, 50 micrograms and 200 micrograms q.i.d. Ulcer healing rates following 4 weeks were 39%, 51%, and 58% in the misoprostol 50 micrograms, 200 micrograms, and cimetidine treatment groups, respectively. There was no statistically significant difference in the healing rates at 4 weeks between the misoprostol 200 micrograms and cimetidine 300 mg q.i.d groups (P = 0.16). The healing rate with the misoprostol 200 micrograms dose was significantly better than with the 50 micrograms dose (P = 0.008). Cimetidine 300 mg relieved global pain significantly better than misoprostol 200 micrograms at 2 weeks (P = 0.047) but not at 4 weeks. The 200 micrograms dose of misoprostol relieved pain significantly better than the 50 micrograms dose at 4 weeks (P = 0.019), but not at 2 weeks. All 3 treatments were well tolerated. Severe adverse events were rare. The efficacy of enprostil, another PGE2 analog, on gastric ulcer healing was also found to be better than placebo and not significantly different from ranitidine. The synthetic prostanoids, misoprostol and enprostil, appear to be safe and effective in the treatment of gastric ulcer.