Effects of oral cyclotropium bromide, hyoscine N-butylbromide and placebo on gastric emptying and antral motor activity in healthy man.

Cyclotropium bromide, a new antimuscarinic agent, inhibits gastrointestinal motility in animals at lower doses than those required to inhibit gastric acid secretion and salivation. In man, cyclotropium bromide suppresses fasting and meal stimulated colonic motility. This study investigated the effects of single oral doses of 60 mg cyclotropium bromide, 60 mg hyoscine N-butylbromide and placebo on gastric emptying and on antral motor activity. Twenty four healthy men (mean age 25 years) participated in three experiments one week apart. The drugs were administered, in random double blind fashion, 30 minutes before the ingestion of a semisolid test meal labelled with 74 MBq (2 mCi) 99mTc sulphur colloid. A gamma camera coupled to a computer monitored gastric emptying together with amplitude, frequency, and propagation velocity of antral contractions. Cyclotropium bromide and, to a lesser degree, hyoscine N-butylbromide delayed gastric emptying and reduced contraction amplitude, but did not affect frequency and propagation velocity of antral contractions. Cyclotropium bromide was significantly more active than hyoscine N-butylbromide; the effects of hyoscine N-butylbromide differed significantly from placebo. Antral contractile activity was present all the time. After cyclotropium bromide, there was a significant correlation between antral contraction amplitude and gastric emptying. No adverse side effects occurred with any one treatment. In conclusion, cyclotropium bromide markedly inhibits gastric emptying and reduces antral contraction amplitude.