GASTRIC-ACID SECRETION AND PLASMA GASTRIN DURING SHORT-TERM TREATMENT WITH OMEPRAZOLE AND RANITIDINE IN DUODENAL-ULCER PATIENTS

The aim of this study was to evaluate changes in peptic acid secretion, and in fasting and meal-stimulated plasma gastrin levels after a 7-day course of omeprazole 30 mg/day or ranitidine 300 mg/day, administered in accordance with a randomized, double-blind, double-dummy protocol. Ten duodenal ulcer patients were studied. Their acid and pepsin output was determined prior to and after treatment. Plasma gastrin levels were also determined under basal conditions on day 7 of treatment, and 24 hours after the last administration of the drug. With regard to acid output, omeprazole resulted in a 98 % reduction in BAO and an 80 % reduction in PAO, both significantly greater than those achieved with ranitidine (BAO 50 %, PAO 25 %). No significant changes in pepsin secretion were observed. The increase in fasting plasma gastrin observed after ranitidine and oemprazole was 86 % and 242 %, respectively, on day 7, and 13 % and 103 % twenty-four hours after final dose. Increases in meal-stimulated plasma gastrin were, respectively, 126 % and 125 % on day 7 and 8 after omeprazole, whereas the increase with ranitidine was 62 % only on day 7 of treatment, with subsequent normalization. In addition to confirming the well-known effect of omeprazole on the physiology of gastric secretion, our data show that administration of therapeutic doses of traditional H2-antagonists is accompanied by a secondary hypergastrinemia, which is rapidly reversible after discontinuation of therapy.