Reduction of plasma triiodothyronine (T3) induced by propranolol

Clin Endocrinol (Oxf). 1977 Jun;6(6):405-10. doi: 10.1111/j.1365-2265.1977.tb03322.x.


The effect of propranolol on plasma triiodothyronine (T3), thyroxine (T4) and triiodothyronine uptake by Sephadex G-25 (RT3U%) was studied in fourteen thyrotoxic patients and eight normal volunteers. 40 mg of propranolol as a single oral dose caused significant reduction in total serum T3 which began 60 min after administration. No significant changes were observed in T4 and RT3U% values. Plasma T3 levels remained suppressed during a 5 day course of treatment with propranolol. These results suggest that propranolol has a direct effect on peripheral metabolism of T3 rather than on thyroid hormone secretion.

MeSH terms

  • Adult
  • Female
  • Graves Disease / blood
  • Humans
  • Male
  • Propranolol / administration & dosage
  • Propranolol / pharmacology*
  • Thyroxine / blood
  • Time Factors
  • Triiodothyronine / blood*


  • Triiodothyronine
  • Propranolol
  • Thyroxine