RELATIONSHIP BETWEEN PLASMA PROPRANOLOL CONCENTRATION AND RELIEF OF ESSENTIAL TREMOR

The relationship between plasma propranolol concentration and relief of essential tremor was examined in 11 patients during treatment with oral racemic propranolol in doses of 30 to 640 mg/day. Although propranolol decreased tremor in all 11 patients, the degree of improvement varied widely in individuals to the plasma propranolol concentration. In seven patients, optimum reduction in tremor occurred at plasma propranolol concentrations below 20 ng/ml (0.077 μmol/l) and, in three others, below 40 ng/ml (0.154 μmol/l). It is concluded that the optimum response of essential tremor to propranolol is achieved at relatively low plasma propranolol levels, levels which are obtained by daily propranolol doses of 120-240 mg.