Conditions that Require Higher Doses of Thyroid Medication (Levothyroxine)

ENDOCRINOLOGY, Pharmacy and Therapeutics

Will need to increase the dose of levothyroxine if the patient is:

  • Pregnant (about 30% increase by week 8),
  • On estrogen replacement, or
  • On meds that accelerate T4 catabolism  (e.g. phenytoin, phenobarbital),
  • On meds that impair absorption of levothyroxine. Sucralfate, cholestyramine, Fe or Ca supplements.
  • Has a GI condition that impairs levothyroxine absorption such as:
    • Atrophic gastritis
    • H. Pylori infection (H. pylori gastritis)
    • Chronic proton pump inhibitor use
    • Celiac disease
    • IBD etc.)

Treatment dose is Levothyroxine 1.5-1.7mcg/kg/d.

If H. pylori infection is the cause of the increasing need of levothyroxine, treating it reverses this effect. Following the eradication of the infection, a reduction of the levothyroxine dosage by 30% or more will often be required.

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