Metoprolol and propranolol in essential tremor: a double-blind, controlled study.

Abstract

Single oral doses of propranolol (120 mg), metoprolol (150 mg) and placebo were given in a randomized, double-blind fashion to 23 patients with essential tremor. Both .beta. blockers were significantly more effective than placebo in reducing the magnitude of tremor. The decrease in tremor produced by metoprolol (47, SE of mean 9%) was not significantly different from that observed after propranolol (55, SE of mean 5%). Tachycardia on standing was antagonized by both drugs to a similar extent. Metoprolol may represent a valuable alternative to propranolol in the treatment of essential tremor. The data is consistent with the hypothesis that the tremorolytic effect of .beta. blockers in these patients may be unrelated to peripheral .beta.-2 adreno-receptor blockade, being possibly mediated by other central or peripheral modes of action of these drugs. It cannot be excluded that at the dose used, metoprolol had lost its relative cardio-selectivity and that the reduction in tremor was mediated by competitive antagonism at .beta.-2 receptor sites in skeletal muscle.