[Human acid secretion during daily administration of H2-blockers]

The potency and duration of a single dose of ranitidine and famotidine were compared in placebo-controlled studies. In addition, the effect of a single night-time dose of famotidine (40 mg) on gastric acid secretion and basal hormone levels was assessed before, during and after a 28-day treatment. Basal acid secretion was depressed by about 73% and 76% 12 hours after 300 mg ranitidine and 40 mg famotidine respectively. Pentagastrin-stimulated acid output was reduced by about 26% and 29%. 20 hours after both drugs, basal secretion was still inhibited by about 60%, whereas no effect on stimulated acid secretion could be detected. Nocturnal gastric acidity (23.00-07.00) was inhibited from 35.8 +/- 4.6 mmol/l to 1.8 +/- 0.5 mmol/l (94% inhibition) by 40 mg bedtime famotidine , and to 1.7 +/- 0.5 mmol/l (95% inhibition) by 300 mg ranitidine. Both drugs significantly reduced H+ concentrations during the following day. On day 29, i.e. 12 hours after the last famotidine dose, basal and stimulated acid secretion was reduced by some 50% and 26% respectively. On day 35, gastric acid output had returned to pretreatment values. Basal levels of prolactin, testosterone etc. were unchanged by 28-day famotidine treatment. Rantidine and famotidine may therefore be used as a single night-time dose in the acute treatment of peptic ulcer disease.