hypothyroidism
HYPOTHYROIDISM
Hypothyroidism is a common endocrine disorder where in the thyroid does not make enough thyroid hormone.
Subclinical/mild hypothyroidism refers to the state of slightly increased serum TSH with normal serum FT4 in patients who are usually asymptomatic.
Most common cause of primary hypothyroidism is autoimmune thyroiditis or Hashimoto's disease.
Levothyroxine is the first-line agent for treatment of hypothyroidism.

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 suppress TSH secretion
    • Long T½, slow onset, regular bioconversion which is appropriately regulated by the tissues to the biologically active compound T3
  • Effects: Safe & predictable effects
    • Requires several wk to achieve peak therapeutic effects w/ 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 & 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 suppress TSH secretion
  • Generally not recommended for routine treatment of hypothyroidism due to its rapid onset & turnover which requires more frequent administration & increases the risk of hyperthyroidism
  • Useful in management of myxedema coma (when its rapid onset & short duration of action are required)
  • Effects: Require 3 days to achieve peak therapeutic effects
Note: Desiccated thyroid hormones (w/ variable proportion of T3 & T4), combinations of thyroid hormones & T3 alone are generally not recommended for treatment of hypothyroidism.
Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Endocrinology - Malaysia digital copy today!
Sign In To Download
Editor's Recommendations
Most Read Articles
3 days ago
In patients with type 2 diabetes, obesity may be protective against vision-threatening diabetic retinopathy, a recent Korea study has shown.
6 days ago
Atrial fibrillation (AF) carries an excess risk of stroke recurrence independent of comorbidity with and heart failure (HF), while HF without AF also poses a significant risk of recurrence, a study has shown.
Roshini Claire Anthony, 2 days ago

Men with metastatic hormone-sensitive prostate cancer (mHSPC) who receive testosterone suppression therapy may have a better survival outcome with the addition of enzalutamide over other non-steroidal anti-androgen (NSAA) therapies, according to the phase III ENZAMET* trial.

07 Jun 2019
Low-dose aspirin therapy does not confer significant benefits to elderly patients with hypertension, but treatment appears to increase the risk of haemorrhagic events, suggest a Japan study.