Effect of pirenzepine on meal-stimulated acid secretion and gastrin release in normal man

The effect of increasing doses of pirenzepine, a tricyclic compound and new antiulcer drug, on meal-induced gastric acid secretion, gastrin release and gastric emptying of the liquid meal, was investigated in eight healthy volunteers. Gastric acid secretion was assessed using intragastric titration technique. Intra-muscularly administered doses of pirenzepine tested were 0 (placebo), 0.1, 0.25 and 0.5 mg.kg-1. With increasing doses of pirenzepine a dose-related reduction of meal-stimulated acid response was noticed amounting to 53% of control values with the highest dosage. The IC 50 value is close to 200 ng.ml-1. Initial but not total gastric emptying of the liquid protein-meal was slowed by 0.5 mg.kg-1 pirenzepine dose. Gastrin responses to the meal were reduced in a dose dependent manner although to a lesser degree.