Propranolol and the hypercalcaemia of thyrotoxicosis

Abstract

Abstract. The effect of propranolol on serum calcium was studied in 25 patients with thyrotoxicosis including 5 with hypercalcaemia. In patients with hypercalcaemia iv propranolol significantly reduced serum calcium. Oral therapy 160 mg/day reduced calcium non-significantly from 2.72 ± 0.09 (mean ± SD) to 2.59 ± 0.13 mmol/l, however on 320 mg/day the reduction (to 2.5 ± 0.15 mmol/l) was significant. In normocalcaemic patients oral propranolol did not influence serum calcium. Both in hyper- and normocalcaemic thyrotoxic patients propranolol increased (P < 0.01) serum phosphate.