The aim of this study was to compare two different dosages of misoprostol (200 microg two or three times daily: MISO TID or MISO BID groups) with ranitidine (150 mg twice daily: RAN group) in the short-term prevention of acute gastroduodenal lesions induced by naproxen (500 mg twice daily).
Seventy patients (62 females, 8 males, mean age 54 yr) affected by rheumatoid arthritis (54 patients, 77%) or osteoarthritis (16 patients, 23%) with endoscopically normal mucosa were randomized to receive one of the three treatments for 2 wk. The gastroduodenal mucosa damage was scored according to a modified 0-5 endoscopic scale.
Sixty-five patients (21 of 23 patients in the MISO TID group, 22 of 23 patients in the MISO BID group, and 22 of 24 patients in the RAN group) underwent a final endoscopy, while five patients dropped out for nonmedical reasons. With intent-to-treat analysis, the percentages of significant gastric lesions was 13, 9, and 46%, respectively, for the MISO TID, MISO BID, and RAN groups (MISO TID vs RAN, p < 0.01; MISO BID vs RAN, p < 0.01). Nine patients developed an ulcer: two in the MISO TID group (one gastric ulcer and one duodenal ulcer); two in the MISO BID group (two gastric ulcers); and five in the RAN group (three gastric ulcers, one duodenal ulcer, and one patient had both gastric and duodenal ulcers).
These results show that misoprostol at 400-600 microg daily is significantly more effective than ranitidine in the short-term prevention of naproxen-induced gastric lesions. The lower dose retained mucosal protective activity that was statistically indistinguishable from that of misoprostol at 200 microg t.i.d.