title: Plasma propranolol steady state concentrations in thyroid disorders.
abstract: Plasma propranolol steady-state concentrations (Css) were measured in 24 hyperthyroid and 6 hypothyroid patients before and after correction of the thyroid disorder. Following treatment of hyperthyroidism by surgery, antithyroid drugs or radioiodine, there was a significant rise in the plasma propranolol Css in patients receiving propranolol either 160 mg/day, 240 mg/day, or 480 mg/day. In addition, in five patients the area under the plasma propranolol concentration versus time curve during a dosing interval increased significantly from 405 ng/ml/h when hyperthyroid to 778 ng/ml/h when euthyroid. In the hypothyroid patients given propranolol 160 mg/day concomitantly with 1-thyroxine therapy the plasma propranolol Css fell significantly when euthyroid. There was a small but significant increase in the degree of plasma protein binding of propranolol, following treatment of hyperthyroidism and a significant decrease following correction of hypothyroidism. It is concluded that thyroid disorders markedly influence propranolol handling.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000378:metabolism; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood* / Q000628:therapy; D007037:Hypothyroidism / Q000097:blood* / Q000188:drug therapy; D008875:Middle Aged; D011433:Propranolol / Q000097:blood*; D011485:Protein Binding; D013974:Thyroxine / Q000627:therapeutic use
chemical_list: D001798:Blood Proteins; D011433:Propranolol; D013974:Thyroxine