Daily administration of short-acting liothyronine is associated with significant triiodothyronine excursions and fails to alter thyroid-responsive parameters
J Jonklaas, KD Burman
Participants with hypothyroidism were studied prospectively at an academic institution. Patients were switched from levothyroxine monotherapy to liothyronine monotherapy with 15 μg liothyronine for two weeks, and then continued liothyronine at doses of 30-45 μg for a further four weeks in an open-label, single-arm study. Weekly trough levels of T3 were documented. In addition, hourly T3 concentrations immediately following liothyronine tablet administration were documented for eight hours during the sixth week of therapy. Serum thyrotropin (TSH) and free thyroxine (fT4) concentrations were documented. Biochemical markers, markers of energy metabolism, anthropometric parameters, well-being, and hyperthyroid symptoms were also assessed.