Variability in individual response to various doses of omeprazole

Abstract
This study was carried out in order to perform a combined prospective assessment of the individual pharmacodynamic response and of duodenal ulcer healing in patients treated with three different doses of omeprazole. Ninety-nine patients with endoscopically proven duodenal ulcers were subdivided into three parallel groups of 33 cases, who were randomly assigned to receive orally at 0800 hr, in single blind fashion, either 10 mg, 20 mg, or 40 mg of omeprazole. All of them underwent continuous intragastric pH monitoring both in basal conditions and on the fifth day of each dose regimen; ulcer healing was then assessed endoscopically after four weeks of treatment. All three doses of omeprazole caused pH values to increase significantly (PP<0.05). A dose of omeprazole as low as 10 mg produces a consistent acid inhibition in 70% of cases, and this can be associated with frequent, but unpredictable, clinical benefit. The acid suppression obtained with omeprazole 20 mg is remarkable in the majority of patients, but is poor in 10% of cases, and this finding may result in clinical nonresponse. The 40-mg dose of omeprazole produces the most uniform response and is only occasionally unsuccessful in the clinical setting.