An endoscopic comparison of the effects of alendronate and risedronate on upper gastrointestinal mucosae

OBJECTIVES: The nitrogen-containing bisphosphonates alendronate and risedro nate have been reported to have upper gastrointestinal (GI) safety and tole rability profiles comparable to those of placebo. Nevertheless, both agents have demonstrated similar potential for irritation of gastric mucosa at hi gh doses in preclinical studies. The present-study compared the potential f or alendronate and risedronate to produce endoscopic upper GI mucosal irrit ation using the highest approved dosage regimens for the two agents. METHODS: This was a multicenter, randomized, parallel-group, double-blind, placebo-controlled trial in which a total of 235 patients (men or postmenop ausal women, aged 45-80 yr) with normal upper GI endoscopy at baseline rece ived 28-day treatments with the following: alendronate 40 mg/day (N = 90), risedronate 30 mg/day (N = 89), placebo (N = 36), or placebo with aspirin 6 50 mg q.i.d. for the last 7 days (N = 20). Endoscopy was repeated on day 29 using standardized scoring scales. RESULTS: After 28 days of treatment, the alendronate and risedronate groups had comparable mean gastric and duodenal erosion scores that were signific antly lower than those of the aspirin group. Esophageal scores were compara ble in all groups. Gastric ulcers and/or large numbers of gastric erosions occurred in approximately 3% of alendronate and risedronate patients versus 60% with aspirin. Both bisphosphonates were clinically well tolerated. CONCLUSIONS: The potential for gastroduodenal irritation is: similar for al endronate and risedronate and is markedly less than for aspirin. The findin gs of this study, together with the large placebo-controlled clinical trial experience with both agents and extensive epidemiological data for alendro nate, suggest that the risk for clinically important gastric irritation wit h these bisphosphonates is very low, even at the highest available doses. ( C) 2000 by Am. Cell. of Gastroenterology.