Aspirin causes direct gastric damage by topical
irritant effects and indirect damage via systemic inhibition of
cyclooxygenase synthesis and microcirculation injury. The question of a possible synergistic relation between the presence of Helicobacter pylori
infection and
aspirin use on gastric damage is not resolved. The pathogenesis of small intestinal and colonic damage is less well understood; an increase in intestinal permeability and
free radical synthesis are suggested. Gastric damage predominates. Gastroduodenal lesions from
aspirin have been documented in endoscopy studies. The lesions occur rapidly, even for low-dose
aspirin. The association of
aspirin consumption with upper gastrointestinal
bleeding has been well established. The main risk factors are advanced age, concomitant use of nonsteroidal antiinflammatory drugs and history of
ulcer. Low-dose
aspirin are associated with increased risk of gastrointestinal
bleeding and this risk is dose-dependant. Chronic
aspirin consumption can cause
iron 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 perforation.
Aspirin can also damage other areas of the gastrointestinal tract. Oesophageal
injuries (oesophagitis and
stricture) have been reported.
Aspirin is associated with variceal
bleeding episodes in patients with
cirrhosis. The adverse effects of
aspirin on the small bowel are perforation,
bleeding, increasing permeability. The adverse effects of
aspirin on the large intestine are perforation,
bleeding,
collagenous colitis and
anorectal stenosis with
suppositories containing
aspirin. Direct clinical data regarding prophylaxis with co-administration of a
protective drug are not yet available for
aspirin.
FUTURE PROSPECTS AND PROJECTS: Patients should be made aware of adverse gastrointestinal effects due to
aspirin. Further studies regarding prophylactic
therapy of low-dose
aspirin induced gastroduodenal lesions, which identify a subset of patients who may be at higher risk than the low-dose
aspirin population as a whole, are warranted.