Effect of the beta adrenergic blocking agent propranolol on essential tremor.

A double blind trial of a single 40 mg dose of the beta adrenergic blocking agent propranolol in the treatment of essential tremor produced significant reduction of tremor in four of five patients, but this effect was transient and had considerably diminished within four hours. A month's double blind clinical trial of propranolol, in a dose of 30 mg three times a day, showed that the active drug gave statistically better results than placebo for the attenuation of tremor. The mode of action of propranolol in the reduction of essential tremor is probably a dual one, due both to blockage of peripheral beta receptors and to a central depressant effect.