Protective effect of prostaglandin E2 in the gastrointestinal tract during indomethacin treatment of rheumatic diseases.

Nonsteroidal antiinflammatory drugs (NSAID) induce the formation of bleeding gastric and intestinal ulcers in experimental animals. The damage can be prevented by prior local administration of prostaglandins, indicating that prostaglandins have protective properties on the gastrointestinal mucosa. The protective effect was studied in humans by measuring the fecal blood loss during indomethacin treatment of 18 patients with rheumatic diseases with and without concomitant oral supplementation with 1 mg prostaglandin E2 three times daily. The study had a randomized double-blind crossover design using 51Cr-labeled erythrocytes as marker of gastrointestinal bleeding. Indomethacin increased the daily fecal blood loss from 1.0 +/- 0.3 to 2.8 +/- 0.6 ml (P less than 0.005). When oral PGE2 was taken concomitantly, the blood loss was reduced to 1.1 +/- 0.2 ml daily (P less than 0.01), i.e., to the control level. Side effects of prostaglandin E2 were negligible, and the beneficial effect of indomethacin on joint status and symptoms was not interfered with. No changes were recorded in repeated blood tests except for a slightly reduced hemoglobin and a small but statistically significant reduction of serum-calcium during indomethacin treatment, an effect hitherto not described in normocalcemic human subjects. A protective effect on the gastrointestinal mucosa by oral prostaglandin E2 has by the present study been demonstrated also in humans. The protection is unrelated to the gastric acid secretion, which is not inhibited by oral prostaglandin E2. The finding may have clinical application, as gastrointestinal side effects and bleeding are common reasons for discontinuation of NSAID in patients with rheumatic diseases.