Clinicopharmacological Study on the Effect of β-Blocker to the Various Types of Tremors

Abstract

A study was conduceted to investigate the effect of a β-blocker upon 96 patients with various types of tremors after single administration of 15 mg of bufetolol hydrochloride or pindolol. Both drugs are known as β-blockers which have little inhibitory effect upon the central nervous system.Our 96 patients consisted of 26 with parkinsonian tremors and 70 with positional tremors. During examination, patient with parkinsonian tremors sat on a chair with his arms held down, while patient with positional tremors held his arms straight forward with his wrists and fingers extended.A tremor curve was lead from patient's hand before and 75 to 90 minutes after administrating the β-blocker, and the changes in the amplitude of tremors were examined. Furthermore, we examined an increase of the amplitude of tremors by the mirror-drawing test and by a subcutaneous injection of 0.15〜0.4mg of adrenaline, and then an inhibitory effect of the β-blocker upon the increase facilitated by these two methods.An inhibitory effect of the β-blocker upon tremors was observed in 67% of patients with parkinsonian tremors due to Parkinson's disease, and in most of the patients with other types of tremors. However, the inhibition was found in complete in most of these cases.The amplitude of tremors showed a marked increase in response to a subcutaneous injection of adrenaline.This increase was almost completely inhibited in all examined cases by administrating the β-blockers prior to the injection.When the mirror-drawing test was conducted, the amplitude of tremors on the site other than the drawing hand increased in most patients with parkinsonian tremors, while it did not increase in almost all patients with positional tremors. When patients with increased tremors by mirror drawing were re-xamined 75 to 90 minutes after administration of the β-blocker, the increase was inhibited in 60% of patients with parkinsonian tremors, though the inhibition was not always complete.No special relationship was found between MAS scores and the effect of the β-blocker upon tremors.On the basis of these results the author discussed pharmacological mechanisms of various tremors and inhibitory effects of β-blocker upon tremors.