The antiarrhythmic activity of N-alkyl-1,2-diphenylethanolamines

The activity of N-alkyl-1,2-diphenylethanolamines against CaCl2-induced cardiac arrhythmia was evaluated in the rat. The potencies of the compounds were compared with that of the established calcium ion-channel blocker, verapamil. The N-methyl, N-ethyl, and N-isobutyl derivatives as well as verapamil at doses of 2-8 mumols kg-1 protected the animals against the induced arrhythmia. The potency order was verapamil greater than N methyl greater than N-ethyl greater than N-isobutyl derivatives. The N-isopropyl and N-butyl derivatives were inactive. The antiarrhythmic activity of the compounds was not due to local anesthetic activity but may be caused by calcium-channel inhibition.