The antigastrolesive activity of rioprostil, a 16-methyl prostaglandin-E1 analogue in healthy volunteers.

The antigastrolesive activity of rioprostil, an orally effective synthetic 16-methyl analogue of prostaglandin-E1, with potent antisecretory and antigastrolesive properties in animals, is evaluated in a series of studies involving 166 healthy male volunteers. Three double-blind, randomized, parallel, placebo-controlled studies are conducted independently at three study centres. In two studies the protective effect of rioprostil against endoscopically-demonstrated mucosal changes caused by concurrent administration of aspirin is examined. The third study evaluates the inhibitory effect of rioprostil on faecal blood loss produced by co-administration of aspirin. Oral doses of rioprostil give significant dose-dependent protection against aspirin-induced mucosal changes. The total mucosal scores at day 3 and day 11 are significantly lower in each of the rioprostil + aspirin groups compared with the aspirin treated group. The total mucosal scores generally decrease with increasing rioprostil dose. Daily faecal blood loss is significantly lower in each of the groups of subjects treated with rioprostil + aspirin, compared with those treated with aspirin + placebo. This study shows that rioprostil provides significant protection against mucosal damage caused by high doses of concomitantly administered aspirin.