Protection of human gastric mucosa against aspirin - enteric coating or dose reduction?

Background: Aspirin is widely used for cardiovascular prophylaxis. Aim: To compare the effectiveness of two widely-used strategies-dose reduct ion and enteric coating-for the minimization of gastric mucosal injury or t oxicity. Methods: Twelve healthy volunteers were studied. On four separate occasions each received, under blinded conditions, five daily doses of plain aspirin 300 mg, plain aspirin 75 mg, enteric-coated aspirin 300 mg or placebo. Ex vivo prostaglandin Ex synthesis was stimulated by the vortex mixing of gast ric mucosal biopsies in Tris saline and measured by radioimmunoassay. Mucos al injury was quantified both by counting erosions and with a visual analog ue scale. Results: All three preparations reduced prostaglandin E-2 synthesis by day five, by (median) 84% for plain aspirin 300 mg, by 80% for enteric coated a spirin 300 mg and by 63% for plain aspirin 75 mg. There was little mucosal injury prior to the start of each dose and period and no significant change with placebo, Plain aspirin caused a dose-dependent mucosal injury, with t wo (median, IQR 0-7) gastric erosions after five days of plain aspirin 75 m g, and 18 (2-26) after five days of plain aspirin 300 mg. With enteric-coat ed aspirin 300 mg there were 0 (0-1) gastric erosions (P = 0.003 compared t o plain aspirin 300 mg P = 0.11, compared to plain aspirin 75 mg). Conclusion: Enteric coated aspirin reduces acute gastric mucosal injury to placebo levels, despite its inhibition of prostaglandin synthesis. Enteric coating is an appropriate strategy for the prevention of gastric mucosal da mage induced by low-dose aspirin, which warrants systematic clinical evalua tion.