Converting a Patient from Levothyroxine to Liothyronine

Initial Assessment and Monitoring

Evaluate current thyroid function with TSH, free T4, and free T3 levels to establish baseline status, as recommended by the American College of Clinical Oncology 1
Review patient's medical history for cardiac disease, osteoporosis, or other conditions that might increase risk with liothyronine therapy, according to the American Heart Association guidelines 2
Monitor thyroid function tests (TSH, free T4, free T3) 4-6 weeks after each dose adjustment, as suggested by the American College of Clinical Oncology 1
Target a normal TSH within reference range unless specific indications for TSH suppression exist (e.g., thyroid cancer), as recommended by the American Thyroid Association 2

Patients with cardiac disease require more careful monitoring due to potential cardiovascular effects, as advised by the American Heart Association 2
Avoid rapid dose escalation, which may precipitate cardiac symptoms, especially in elderly or those with cardiovascular disease, as warned by the American Geriatrics Society 2
Monitor closely for overtreatment, which can lead to subclinical or overt hyperthyroidism with risks of atrial fibrillation and bone loss, as cautioned by the American Thyroid Association 2
Monitor for signs of hyperthyroidism: palpitations, anxiety, insomnia, weight loss, heat intolerance, as indicated by the Journal for ImmunoTherapy of Cancer 3