Role of misoprostol in reducing aspirin-induced gastrointestinal blood loss in arthritic patients.

Nonsteroidal anti-inflammatory drugs are used to control pain and inflammation in arthritic disorders. When used at recommended anti-inflammatory dose levels, however, they often produce injury to the gastric and duodenal mucosa and concomitant blood loss. A double-blind, parallel, placebo-controlled study was conducted to assess the effectiveness of misoprostol, a synthetic analogue of prostaglandin E1, in preventing gastrointestinal blood loss induced by acetylsalicylic acid in patients with degenerative joint disease. Forty-five arthritic patients (22 women and 23 men) were admitted to the study. All patients had received treatment with 3,900 mg of acetylsalicylic acid per day in four divided doses for at least two weeks and continued to receive that regimen for the duration of the study. Red blood cells were tagged with chromium-51, and fecal blood loss was determined from Days 4 to 7. Patients with a mean blood loss of at least 1.5 ml per day were randomly allocated to receive either placebo or 200 micrograms of misoprostol four times daily for seven days. Fecal blood loss was measured daily, and the results were compared with baseline determinations. Of 41 patients who completed the study, 19 were treated with misoprostol. Of these, 11 patients (57.9 percent) had at least a 50 percent reduction in blood loss. Of 22 patients receiving placebo, only one had a 50 percent reduction in blood loss (p = 0.003; Fisher's exact test). Mean blood loss in patients using misoprostol was reduced from 3.65 +/- 2.51 to 1.57 +/- 0.86 ml per day, whereas among those taking placebo, mean blood loss did not significantly change (2.98 +/- 1.24 to 2.79 +/- 1.63 ml per day). The difference in blood loss between the misoprostol and placebo groups was significant (p = 0.0023; Wilcoxon test). In those patients who completed the study, no significant changes were detected on laboratory tests. In conclusion, misoprostol effectively reduced fecal blood loss in arthritic patients treated with acetylsalicylic acid.