Non‐Selective and Selective β‐1‐Adrenoceptor Blocking Agents in the Treatment of Hyperthyroidism

Abstract

Treatment for 1 mo. with propranolol or atenolol, a selective .beta.-1-adrenoceptor blocking agent, was evaluated in 20 hyperthyroid patients. The patients improved to the same extent on either drug as shown by a clinical diagnostic index. Basal metabolic rate decreased by 11% during both treatments but was unchanged in 7 untreated hyperthyroid controls. Thyroxine concentration did not change during any treatment. During propranolol treatment T3 [triiodothyronine] decreased from 4.6 to 3.9 nmol/l; no changes were observed during atenolol treatment or in the control group. No significant changes were seen in free T4, free T3 or r[reverse]T3 concentrations on any treatment, although free T3 decreased slightly during propranolol treatment. The improvement of the clinical symptoms of hyperthyroidism cannot be explained by diminished thyroid hormone concentrations in serum since the reduction was small during propranolol and absent during atenolol treatment.