Levothyroxine
A prescription thyroid hormone replacement used to treat hypothyroidism and certain thyroid cancers.
What it is
Levothyroxine sodium is FDA-approved as replacement therapy for adults and pediatric patients 6 years and older with primary, secondary, or tertiary hypothyroidism, and as an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer. It is not indicated for benign thyroid nodules, nontoxic diffuse goiter in iodine-sufficient patients, or transient hypothyroidism during recovery from subacute thyroiditis.
How it is commonly taken
The FDA label directs administering levothyroxine sodium as a single daily oral dose, on an empty stomach, one-half to one hour before breakfast.
Food and timing considerations
The FDA label recommends taking levothyroxine at least 4 hours apart from agents known to interfere with its absorption, including calcium and iron supplements and some antacids.
Known interaction categories
- Use caution
- Insufficient evidence
- Monitor
Published interaction pages on this site
- Levothyroxine and CalciumUse caution
- Levothyroxine and AtorvastatinInsufficient evidence
- Levothyroxine and IronUse caution
- Levothyroxine and CiprofloxacinInsufficient evidence
- Levothyroxine and SertralineMonitor
- Levothyroxine and Vitamin DInsufficient evidence
- Levothyroxine and WarfarinInsufficient evidence
- Levothyroxine and CreatineInsufficient evidence
- Levothyroxine and SpironolactoneInsufficient evidence
- Levothyroxine and St. John's WortInsufficient evidence
- Levothyroxine and CaffeineInsufficient evidence
- Levothyroxine and Vitamin KInsufficient evidence
- Levothyroxine and Vitamin B12Insufficient evidence
- Levothyroxine and CopperInsufficient evidence
- Levothyroxine and ZincInsufficient evidence
- Levothyroxine and PotassiumInsufficient evidence
- Levothyroxine and LisinoprilInsufficient evidence
- Levothyroxine and TurmericInsufficient evidence
- Levothyroxine and CoQ10 (Coenzyme Q10)Insufficient evidence
- Levothyroxine and DoxycyclineInsufficient evidence
- Levothyroxine and OmeprazoleMonitor
- Levothyroxine and MagnesiumMonitor
- Levothyroxine and MetforminInsufficient evidence
- Levothyroxine and MelatoninInsufficient evidence
- Levothyroxine and ProbioticsInsufficient evidence
Sources
Last reviewed 2026-08-22
Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.