The antisecretory effects of zaltidine, a novel long-acting H2-receptor antagonist, in healthy volunteers and in subjects with a past history of duodenal ulcer

The potency and duration of the antisecretory action of zaltidine, a novel H2-receptor antagonist, have been examined in healthy volunteers and in patients with previous duodenal ulceration. In eight healthy male volunteers single oral doses of 5 mg, 25 mg and 100 mg produced dose-related inhibition of basal and pentagastrin-stimulated acid output (M.A.O.) with an estimated ID50 of 40 mg for the latter. In eight subjects with duodenal ulceration single 100 mg and 200 mg doses produced 85% and 97% inhibition of M.A.O. at peak (3 h post-dose) and 20% and 23% inhibition at 24 h, respectively; inhibition of basal acid output was 97% at 3 h and 50% at 24 h with both doses. The long duration of action of zaltidine is ascribed to its relatively slow elimination from the plasma.