Name: Liothyronine sodium (Cytomel)
Class: Thyroid Hormone
Mechanism: Sodium salt of T3. T3/T4 synergize w/GH effects, increase BMR, potentiate catecholamine effects on heart, promote lipolysis, and decrease serum cholesterol.
Absorption: Oral ® 95% absorption.
Dist.: Poor placental transfer ® okay for pregnant E. Little in milk (use cautiously).
Metabolism.: Hepatic conjug. w/glucuronic & sulfuric acids.
Excretion, t½: Bile; some lost in stool due to enterohepatic circ. £ 2 d.
Toxicity/S.E.s: Salicylates and dicumarol compete for albumin binding sites ® marked increase of free levels.
Utility: Preferred in treatment of myxedema coma. Treat hypothyroidism and goiter (not due to iodine deficiency or hyperthyroidism).
Special Features: 50-75 mg/d. 4x the potency of levothyroxine sodium, but same efficacy.