Font Size

Thyroid Medications (cont.)

Drug Interactions with L-thyroxine

L-thyroxine and other medications

Many other medications can affect the way L-thyroxine is absorbed from the gut. Notify your physician if you take L-thyroxine and any of the following medications:

  • ferrous sulfate [(Feostat, Ferrets, Hemocyte, Ircon, Nephro-Fer) or other iron supplements]
  • calcium carbonate [(Alka-Mints, Amitone, Cal-Gest, Calcarb, Calci Mix, Calci-Chew, Caltrate, Chooz, Maalox Antacid Barrier, Maalox Quick Dissolve, Maalox Quick Dissolve Maximum Strength, Mylanta Child, Nephro Calci, Os-Cal 500, Oysco 500, Oyst Cal 500, Oyster Calcium, Oyster Shell, Rolaids Sodium Free, Rolaids Soft Chew, Tums, Tums 500, Tums E-X, Tums Ultra) or other calcium supplements]
  • colestipol (Colestid, Colestid Flavored)
  • cholestyramine (Cholestyramine Light, Locholest, Locholest Light, Prevalite, Questran, Questran Light)
  • sodium polystyrene sulfonate (Kayexalate, Koinex)
  • Aluminum and magnesium containing antacids
  • sucralfate (Carafate) or simethicone (Alka-Seltzer Anti-Gas, Equalize Gas Relief Drops, Gas Aide, Gas-X, Gas-X Extra Strength, Gas-X Infant Drops, Gas-X Maximum Strength, Gas-X Thin Strips Cinnamon, Gas-X Thin Strips Peppermint, Gas-X Tongue Twisters Thin Strips Children's, Genasyme, Infantaire Gas Relief, Little Tummys, Maalox Anti-Gas, Maalox Anti-Gas Extra Strength, Mi-Acid Gas Relief, Mylanta Gas, Mylanta Gas Maximum Strength, Mylicon, Mytab Gas, Phazyme, Phazyme Maximum Strength, Phazyme Ultra, Phazyme-125, Phazyme-95)
  • raloxifene (Evista)
  • Estrogens can increase L-thyroxine requirements due to an increase in thyroid hormone binding proteins in the blood.
  • L-thyroxine can interfere with maintaining adequate blood levels of other medications. Notify your physician if you take L-thyroxine and any of the following medications:
    • digoxin (Digitek, Lanoxicaps, Lanoxin)
    • Anti-diabetic agents
    • theophylline (Elixophyllin, Theo-24, Theo-Time, TheoCap, Theochron, Uniphyl) and caffeine-containing agents
    • warfarin (Coumadin, Jantoven)
Medically Reviewed by a Doctor on 6/11/2014

Must Read Articles Related to Thyroid Medications

Thyroid Facts
Thyroid FAQs The thyroid gland is part of the endocrine (hormone) system. The thyroid gland produces two hormones, thyroxine (T4) and tri-iodothyronine (T3). Diseases of the...learn more >>

Read What Your Physician is Reading on Medscape

Thyroid Disease »

The thyroid gland plays an important role in tissue metabolism and development.

Read More on Medscape Reference »

Medical Dictionary