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!
DOWNLOAD
Editor's Recommendations
Most Read Articles
Roshini Claire Anthony, 07 Nov 2017

Women who are underweight, particularly in their late teens and mid-thirties, may be at risk for early menopause, a recent study found. 

4 days ago
Oestradiol therapy appears to protect certain types of cognition in the presence of stress, suggests a recent study.
17 May 2017
The high-concentration capsaicin patch shows promise in the management of painful diabetic peripheral neuropathy (PDPN), with an effect that is similar to that observed with oral agents but offering systemic tolerability benefits, according to a network meta-analysis.
Audrey Abella, 20 Jan 2017
Diabetes was not a risk factor for total knee replacement (TKR) due to severe knee osteoarthritis, a Singapore study found.