Background: It appears likely that drugs other than NSAIDs may cause ulcers and ulcer complications (e.g. potassium chloride). Alendronate (Fosamax) is used in the treatment and prevention of metabolic bone disease and has also been associated with severe oesophageal damage and stricture. We have previously shown that the dose of alendronate used for Paget's disease (40 mg) causes gastric damage similar to NSAIDs. The usual dose for the treatment of postmenopausal osteoporosis is 10 mg per day.
Aim: To investigate whether the 10 mg dose of alendronate causes gastric ulcers.
Methods: We performed an endoscopist-blind, crossover, randomized, single-centre comparison of 10 mg of alendronate/day and placebo in volunteers aged 40 years or more. Video-endoscopy was used to evaluate the presence and degree of mucosal damage to the oesophagus, stomach, or duodenal bulb after 7 and 14 days of treatment.
Results: Twenty-four healthy volunteers participated, including 15 women and nine men, ranging in age from 41 to 52 years. Visible gastric mucosal damage was present in nine (38%) who received alendronate compared to three (13%) in the placebo group. There was a marked difference in the severity of mucosal damage; there were no ulcers or large erosions in those receiving placebo. In contrast, potentially clinically significant gastric mucosal injury was seen in six subjects receiving alendronate (two developed antral ulcers and four had large (4-8 mm) superficial antral erosions) compared to none in the placebo group (P = 0.0219). One subject developed oesophageal damage in the form of multiple linear superficial erosions in the mid and distal oesophagus. Duodenal injury was not seen.
Conclusion: Alendronate causes gastric ulceration, suggesting that alendronate use may be associated with ulcer complications such as acute upper gastrointestinal bleeding. The results of this study suggest the need for post-marketing surveillance to clarify the nature, frequency and magnitude of any potential gastrointestinal side-effects associated with the use of this drug.