[Administration of ranitidine once in the evening for several weeks: effect on acidity and basal hormone levels in...

The effects of ranitidine (300 mg at night) on gastric acid secretion as well as on basal hormone levels (testosterone, prolactin, dehydro-epiandrosterone etc.) were assessed in 9 healthy volunteers before, during and after a 28-day treatment. On day 29, i.e. 12 h after the last ranitidine dose, basal and stimulated acid secretion was only slightly reduced by some 14 and 12%, respectively. On day 35, gastric acid output had returned to pretreatment values. There were no signs of a rebound phenomenon. Basal levels of prolactin, testosterone, dehydroepiandrosterone etc. were unchanged by 28-day ranitidine treatment. Ranitidine 300 mg at night may, therefore, be used in the treatment of peptic ulcer disease without any negative effect on human gastric acid secretion and basal hormone levels.