Hypothyroidism Treatment
Pharmacotherapy
Levothyroxine
- 1st-line agent for treatment of hypothyroidism
- May be used to manage myxedema coma
- Safe for use in pregnancy
- Actions:
- Used as a replacement therapy in hypothyroidism to substitute thyroid hormone
- Long half-life (T½), slow onset, regular bioconversion which is appropriately regulated by the tissues to the biologically active compound T3
- Effects: Safe and predictable effects
- Requires several weeks to achieve peak therapeutic effects with regular oral dosing
- Due to different bioavailability of the various preparations of Levothyroxine, patients are encouraged to use the same brand of Levothyroxine
- If a change in brand is needed, the patient’s serum TSH should be retested every 6 weeks and dosage of Levothyroxine be re-titrated
Liothyronine
- Actions:
- Short T½, rapid onset
- Biologically active compound (no conversion is necessary)
- Used as a replacement therapy in hypothyroidism to substitute thyroid hormone
- Generally not recommended for routine treatment of hypothyroidism due to its rapid onset and turnover which requires more frequent administration and increases the risk of hyperthyroidism
- Useful in management of myxedema coma (when its rapid onset and short duration of action are required)
- Effects: Require 3 days to achieve peak therapeutic effects