Efficacy of misoprostol in controlling indomethacin induced fecal blood loss in arthritic patients.

Indomethacin, a nonsteroidal anti-inflammatory drug, may cause gastric mucosal damage as shown by fecal blood loss. A randomized, double-blind, placebo-controlled, parallel group study was conducted to determine the effects of 400 mcg b.i.d. misoprostol, a synthetic prostaglandin E1 analog, on intestinal blood loss caused by 50 mg t.i.d. indomethacin. Forty-two arthritic patients, mean age 59 years, received indomethacin for 14 days. Those with baseline blood loss of at least 1.5 ml/day during the first 7 days were randomized to 400 mcg of misoprostol or placebo (days 8 to 14). Fecal blood loss was measured using 51Cr labelled red blood cell technique. Success was defined as a reduction in mean daily blood loss of at least 50% during the treatment period compared to mean daily blood loss during the baseline (pre-treatment) phase. The mean daily blood loss on treatment days 9-15 was not significantly reduced from baseline in either group. These data neither confirm nor deny the effectiveness of misoprostol in reducing fecal blood loss caused by indomethacin. The results may have been confounded by the administration of misoprostol twice daily while indomethacin was administered three times daily. In addition, fecal blood loss as an indicator of gastrointestinal mucosal damage is not a sensitive measure; it is characterized by poor reproducibility and wide fluctuations within individual responses. Inappropriate laboratory techniques may have further reduced the sensitivity and reliability of this procedure.