Oxygen consumption in patients with hyperthyroidism before and after treatment with beta-blockade versus thyrostatic treatment: a prospective randomized study.

Author(s): Jansson S, Lie-Karlsen K, Stenqvist O, Korner U, Lundholm K, Tisell LE

Affiliation(s): Department of Surgery, Sahlgrenska University Hospital, Goteborg, Sweden. Svante.Jansson@dep-surg.gu.se

Publication date & source: 2001-01, Ann Surg., 233(1):60-4.

Publication type: Clinical Trial; Randomized Controlled Trial

OBJECTIVE: To evaluate randomly the effect of thyrostatic treatment (tiamazole) versus selective (metoprolol) and nonselective beta-blockade (propranolol) on whole-body energy metabolism in women with hyperthyroidism. SUMMARY BACKGROUND DATA: beta-blockade is used as an alternative to thyrostatic drugs in the preoperative treatment of patients with hyperthyroidism. beta-blockers have well-established symptomatic effects, but in contrast to antithyroid drugs beta-blockade is thought to lack direct effects on the increased metabolism in hyperthyroidism. METHODS: Whole-body oxygen consumption and carbon dioxide production was measured in a semiopen canopy system with paramagnetic O2 and infrared CO2 sensors. A constant flow generator and the gas-dilution method for calculation of gas flow were used. Anabolic parameters were body weight, triceps skinfold, and arm muscle circumference. RESULTS: Tiamazole normalized oxygen consumption and induced signs of anabolism with improved nutritional state. Metroprolol did not affect oxygen consumption. Propranolol reduced elevated oxygen consumption by 54%. Body weight and other anthropometric assessments were stable after specific and nonspecific beta-blockade, which also led to symptomatic relief in approximately 90% of the patients. CONCLUSION: Tiamazole was the most effective drug to oppose the adverse effects of hyperthyroidism. Therefore, thyrostatic agents are recommended for preoperative treatments of patients with severe catabolic hyperthyroidism. Whenever beta-blockers are chosen for treatment of hyperthyroidism, propranolol (beta 1 + beta 2) has an advantage because it reduces the metabolic rate, whereas selective beta 1-blockade seemed to provide only symptomatic relief, related to the normalization of heart rate.