Gastrointestinal toxicity of aspirin.

Introduction - This review focuses on aspirin-related gastrointestinal side -effects and the mechanism by which aspirin causes gastrointestinal damage. Current knowledge and key points - Aspirin causes direct gastric damage by topical irritant effects and indirect damage via systemic inhibition of cyc looxygenase synthesis and microcirculation injury. The question of a possib le synergistic relation between the presence of Helicobacter pylori infecti on and aspirin use on gastric damage is not resolved. The pathogenesis of s mall intestinal and colonic damage is less well understood; an increase in intestinal permeability and free radical synthesis are suggested. Gastric d amage predominates. Gastroduodenal lesions from aspirin have been documente d in endoscopy studies. The lesions occur rapidly, even for low-dose aspiri n. The association of aspirin consumption with upper gastrointestinal bleed ing has been well established. The main risk factors are advanced age, conc omitant use of nonsteroidal antiinflammatory drugs and history of ulcer. Lo w-dose aspirin are associated with increased risk of gastrointestinal bleed ing and this risk is dose-dependant Chronic aspirin consumption can cause i ron deficiency anaemia. Uncomplicated gastric ulcer (but not uncomplicated duodenal ulcer) is associated with aspirin use, with relative risk 3. Other upper gastrointestinal complications have been reported stenosis and perfo ration. Aspirin can also damage other areas of the gastrointestinal tract O Esophageal injuries (oesophagitis and stricture) have been reported. Aspiri n is associated with variceal bleeding episodes in patients with cirrhosis. The adverse effects of aspirin on the small bowel are perforation, bleedin g, increasing permeability. The adverse effects of aspirin on the large int estine are perforation, bleeding, collagenous colitis and anorectal stenosi s with suppositories containing aspirin. Direct clinical data regarding pro phylaxis with co-administration of a protective drug are not yet available for aspirin. Future prospects and projects - Patients should be made aware of adverse ga strointestinal effects due to aspirin. Further studies regarding prophylact ic therapy of low-dose aspirin induced gastroduodenal lesions, which identi fy a subset of patients who may be at higher risk than the low-dose aspirin population as a whole, are warranted. (C) 2000 Editions scientifiques et m edicales Elsevier SAS.