Pharmacokinetics and pharmacodynamics of oral nizatidine

Nizatidine was studied in six high-acid-secretor (basal secretion, greater than or equal to 5 mEq/hr) male volunteers in a randomized, double-blind, nonbalanced, cross-over, placebo and standard drug-controlled study. Doses of 75 mg, 150 mg, and 300 mg bid were compared with placebo and cimetidine 300 mg qid. Nocturnal acid output was significantly reduced (P less than .01) by all doses of nizatidine (36 +/- 22, 36 +/- 31, and 26 +/- 20 mEq) with 75 mg, 150 mg and 300 mg, respectively, and also by cimetidine (43 +/- 39 mEq) as compared with placebo (101 +/- 61 mEq). Nizatidine also significantly reduced meal-stimulated acid secretion at breakfast (14 +/- 9, 9 +/- 7, and 5 +/- 6 mEq/2 hours with 75 mg, 150 mg, and 300 mg, respectively, P less than .01), at lunch (50 +/- 22, 57 +/- 22 and 50 +/- 35 mEq/2 hours, P less than .05) but did not have any effect at dinner (65 +/- 16, 78 +/- 24, and 71 +/- 17 mEq/2 hours) whereas cimetidine, given every 6 hours, significantly (P less than .01) reduced meal-stimulated acid secretion (25 +/- 16, 27 +/- 20 and 31 +/- 15 mEq/2 hours, breakfast, lunch, and dinner, respectively) as compared with placebo (81 +/- 30, 76 +/- 25, and 66 +/- 16 mEq/2 hours, breakfast, lunch, and dinner, respectively). Both drugs have a similar pharmacokinetic profile. Nizatidine seems to be a promising H2 antagonist, more potent than cimetidine (on an mg/mg basis), and efficacy studies on gastric acid disorders should be performed.