The effect of pirenzepine and L-hyoscyamine on gastric emptying and salivary secretion in healthy volunteers.
Pirenzepine is used in the treatment of peptic ulcer disease as an inhibitor of gastric acid secretion. Recent studies suggest that the mode of action on the stomach may be selectively anticholinergic. The present study was undertaken to compare the effect of pirenzepine on gastric emptying with the effect of a widely used classical anticholinergic drug and of placebo. In a double-blind double-dummy study nine healthy volunteers received 50 mg pirenzepine twice a day, 0.6 mg L-hyoscyamine twice a day, or two placebo tablets twice a day for 4 days before the gastric emptying test. Gastric emptying of a liquid test meal was measured by the method of George. Maximum salivation capacity was registered by the method of Blum 2 and 4 h after the last dose had been given. Gastric emptying was delayed during L-hyoscyamine, whereas the emptying was slightly accelerated by pirenzepine when compared with placebo. The difference between L-hyoscyamine and pirenzepine was statistically significant for the time in which the volume fell to 75% and 50% (p less than 0.01). The salivation was significantly more inhibited by L-hyoscyamine than by pirenzepine. Pirenzepine in doses inhibiting gastric acid secretion does not delay gastric emptying when compared with an equipotent dose of a classical anticholinergic drug, nor does it inhibit salivary secretion as much as L-hyoscyamine. This study therefore confirms our previous conclusion that pirenzepine may indeed be a 'selective' anticholinergic drug acting on gastric secretion.
D000328:Adult; D001285:Atropine / Q000494:pharmacology*; D001570:Benzodiazepinones / Q000494:pharmacology*; D002986:Clinical Trials as Topic; D003864:Depression, Chemical; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects*; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000494:pharmacology*; D010890:Pirenzepine; D012107:Research Design; D012463:Saliva / Q000378:metabolism*; D012472:Salivation / Q000187:drug effects
D001570:Benzodiazepinones; D006635:Histamine H2 Antagonists; D010879:Piperazines; D010890:Pirenzepine; D001285:Atropine