Comparative studies on the effects of beta-adrenergic blockers in essential tremor.

To establish the criteria for the selection of a beta-adrenergic blocking agent (beta-blockers) suitable for the long-term treatment of tremor, 20 patients with essential tremor were treated with five different types of beta-blockers. All beta-blockers were effective for essential tremor, but their efficacy differed. The weaker the intrinsic sympathomimetic activity (ISA) and the more marked the membrane stabilizing activity (MSA), the more marked was the anti-tremor effect. Propranolol, which showed the strongest anti-tremor effect, had no ISA, but its long-term administration induced symptoms of heart failure, such as pretibial oedema, in most cases. In most of these cases, when propranolol was replaced by indenolol, which showed a very slight ISA, the pretibial oedema subsided and well-controlled tremor was maintained over a long period. With regard to efficacy and usefulness, it was thought that the beta-blockers with a very slight ISA and a marked MSA, such as indenolol, was most suitable for the long-term treatment of essential tremor.