INTRODUCTIONHuman prostaglandin synthesis is catalysed by two isoforms of cyclooxygenase: cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). 1±4 While COX-1 appears to perform routine physiological functions (such as gastric mucosal protection), 5 COX-2 appears to synthesize prostanoids that mediate responses to pathological processes (such as in¯ammation). It has been suggested that, when compared to the dual inhibition of currently available COX-1/COX-2 inhibitors, the speci®c inhibition of COX-2 is associated with a lower incidence of gastrointestinal toxicity. 6,7 The hypothesis for this study was that COX-2 inhibition with MK-0966 would be associated with a lower incidence of endoscopic damage than would either ibuprofen or aspirin. In this randomized, single-centre, double-blind, placebo-controlled, parallel-group study, a high dose of MK-0966 (250 mg q.d.) was compared with conventional doses of aspirin and ibuprofen with respect to their effects on the gastric and duodenal mucosae of healthy adult subjects. Ibuprofen was used , or placebo (n 51) in this 7-day, double-blind, parallel-group study. The mucosae were evaluated by endoscopy using a prede®ned scale; scores could range from 0 to 4. The primary end-point was the percentage of subjects who developed a mucosal score ³ 2 (i.e. the development of

Nonsteroidal antiinflammatory drug-induced gastroduodenal mucosal damage observed endoscopically is usually categorized as hemorrhages, erosions, or ulcerations. We undertook this study to determine whether the injury produced by a commonly prescribed NSAID, naproxen, could be reduced by cotherapy with sucralfate or cimetidine and to determine how dependent the differences in the degree of protection against mucosal injury measured were on the scoring system used. Four groups of 20 healthy volunteers with endoscopically normal gastric and duodenal mucosa received naproxen (500 mg twice a day) plus cimetidine (300 mg four times a day or 400 mg twice a day), sucralfate (1 g four times a day), or placebo for seven days. After seven days of therapy, a second endoscopy was performed. Separate scoring systems were used for the presence of hemorrhages, erosions, and a combination of both types of injury. There were significantly fewer mucosal hemorrhages present when naproxen and cimetidine were administered than when naproxen was administered with placebo or sucralfate (placebo vs 300 mg cimetidine, P = 0.04, and placebo vs 400 mg cimetidine, P = 0.006, placebo vs sucralfate, P = 0.26). Both cimetidine dosages resulted in significantly fewer hemorrhages than were present following cotherapy of naproxen and sucralfate (P less than 0.05). In contrast, there was no discernible difference in the mucosal injury between placebo and any drug or between any two active therapies when the injury was evaluated based on the presence of gastric erosions.(ABSTRACT TRUNCATED AT 250 WORDS)

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The effects of various nonsteroidal antiinflammatory drugs on the gastric mucosa were endoscopically evaluated in 40 normal volunteers. Eight groups, each containing five subjects were designed: aspirin (3600 mg/d); placebo; ibuprofen (1600 mg/d); ibuprofen (2400 mg/d); indomethacin (100 mg/d); indomethacin (150 mg/d); naproxen (500 mg/d); and naproxen (750 mg/d). All volunteers took medication for seven days and gastroscopy was carried out on day one and day eight. All findings were documented by photography. Severe gastric mucosal injury occurred with aspirin (P less than 0.05), both doses of indomethacin, and the higher dose of naproxen. Lesser changes were seen with the lower dose of naproxen, both doses of ibuprofen and placebo. The higher doses of ibuprofen, indomethacin, and naproxen caused a greater degree of gastric mucosal injury, but statistical significance was achieved only with naproxen (P less than 0.01). Subjective gastrointestinal complaints generally correlated with endoscopic pathology; however, nine volunteers had evidence of severe injury to the gastric mucosa with no symptomatology. This was confined to the patients on indomethacin, naproxen, and ibuprofen. Aspirin patients all had some degree of symptomatology but to a lesser degree than expected in view of the endoscopic findings.

Alendronate 5 and 10 mg/day for 2 wk was associated with a lower incidence of gastric erosions than aspirin. The incidence of gastric erosions in the alendronate groups did not differ significantly from the placebo group. In this study, unlike aspirin, alendronate did not induce gastric erosions.