Hyperthyroxinemia in patients treated with high-dose propranolol

Am J Med. 1982 Dec;73(6):867-71. doi: 10.1016/0002-9343(82)90778-1.


Six patients with hyperthyroxinemia (five men and one woman) were evaluated for possible hyperthyroidism. All were taking large daily doses of propranolol--480 +/- 155 (+/- SE) mg--for treatment of angina pectoris. The patients had no clinical evidence of hyperthyroidism, although three had small goiters. Further evaluation of the patients revealed elevated serum free thyroxine levels and/or free thyroxine index, low-normal serum triiodothyronine levels, and elevated serum reverse triiodothyronine levels in all six. The thyroid-stimulating hormone response to thyrotropin-releasing hormone was normal in two patients, subnormal in three patients, and absent in one patient. One patient was restudied while receiving low-dose propranolol (80 mg a day), with normalization of all thyroid functional parameters. The data suggest that the abnormalities seen in patients taking high doses of propranolol were due to drug-induced blockade of iodothyronine deiodination. Signs and symptoms of hyperthyroidism are lacking in patients taking large doses of propranolol. If such a patient is discovered to have an elevated serum thyroxine level, a more complete evaluation of thyroid function is necessary before the diagnosis of thyrotoxicosis can be made. The thyrotropin-releasing hormone test may be of particular value in this circumstance.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Angina Pectoris / drug therapy
  • Female
  • Humans
  • Male
  • Middle Aged
  • Propranolol / adverse effects*
  • Propranolol / therapeutic use
  • Thyrotropin-Releasing Hormone / blood
  • Thyroxine / blood*
  • Triiodothyronine / blood
  • Triiodothyronine, Reverse / blood


  • Triiodothyronine
  • Triiodothyronine, Reverse
  • Thyrotropin-Releasing Hormone
  • Propranolol
  • Thyroxine