Effect of antispasmodic drugs on colonic motility. Part I: Laboratory study of the dog.

The inhibitory effect of five antispasmodic preparations, prifinium bromide, hyoscine butylbromide, propinox, trimebutine maleate and phloroglucinol + trimethyl-phloroglucinol on acetylcholine-induced contraction of the colon was investigated in anesthetized dogs. Prifinium bromide was most potent followed by hyoscine butylbromide. The other three preparations had no potent inhibitory effect even when given in a dose of 1000 micrograms/kg. The ED50 was 3.1 micrograms/kg for prifinium bromide and 12.3 micrograms/kg for hyoscine butylbromide; the prolonged time of action at ED50 was approximately 30 minutes for prifinium bromide and about 10 minutes for hyoscine butylbromide. From the dog experiments, it became clear that prifinium bromide and hyoscine butylbromide had a relatively potent antispasmodic effect on the colon.