Comparative tolerability profile of omeprazole in clinical trials.

The tolerability of omeprazole was compared to control agents in 68 clinical studies that enrolled a total of 4846 patients, of whom 3096 received omeprazole. The incidence of adverse experiences was independent of omeprazole dose administered, the age of the patients, and the disease treated (duodenal ulcer or endoscopically verified gastroesophageal reflux disease). The most common clinical adverse experiences were headache, diarrhea, abdominal pain, and nausea. The most common laboratory adverse experiences were elevated aspartate aminotransferase and elevated alanine aminotransferase. Omeprazole was well tolerated, and the incidence of clinical and laboratory adverse experiences was similar in patients receiving omeprazole, placebo, cimetidine, or ranitidine.