Levothyroxine — Drug Interactions, Alcohol & Pregnancy Guide
Last reviewed: · Source: US FDA drug label database · 247CanITakeWith Editorial Team
- Levothyroxine is a Thyroid hormone replacement used for Hypothyroidism (underactive thyroid).
- Alcohol: Light alcohol use is generally tolerated with levothyroxine, but regular drinking can impair thyroid function and reduce medication effectiveness.
- Pregnancy: Levothyroxine is safe and essential to continue in pregnancy — hypothyroidism must be well-controlled for healthy fetal development.
- This page covers 3 specific drug combinations with Levothyroxine.
About Levothyroxine
Levothyroxine is the standard treatment for hypothyroidism. It must be taken on an empty stomach, 30-60 minutes before food, and separated from calcium, iron, and antacids by at least 2-4 hours. Dose requirements increase in pregnancy.
Also sold as: Synthroid, Eltroxin, Euthyrox
Levothyroxine at a glance
Levothyroxine is classed as thyroid hormone replacement and is used for hypothyroidism (underactive thyroid). It is a prescription medicine, so doses and combinations should always be agreed with your prescriber or pharmacist.
Typical adult dosing guidance: Individualised; typically 50-200mcg once daily. Your own label or prescription always takes priority over general figures.
Interactions most often flagged
- Iron
- Calcium
- Alcohol
- Pregnancy
Before you combine Levothyroxine with anything new
- Read the patient information leaflet for both products.
- Keep one up-to-date list of every medicine and supplement you take.
- Ask a pharmacist — it is free and takes a couple of minutes.
- Seek urgent medical help if you feel seriously unwell after combining medicines.
Levothyroxine and Alcohol
Light alcohol use is generally tolerated with levothyroxine, but regular drinking can impair thyroid function and reduce medication effectiveness.
Full guide →Levothyroxine in Pregnancy
Levothyroxine is safe and essential to continue in pregnancy — hypothyroidism must be well-controlled for healthy fetal development.
Full guide →Levothyroxine — Drug Combinations
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Frequently Asked Questions
What is Levothyroxine used for?
Levothyroxine is a Thyroid hormone replacement used for Hypothyroidism (underactive thyroid).
What is the maximum adult dose of Levothyroxine?
The maximum adult dose is Individualised; typically 50-200mcg once daily. This is general guidance — always follow the dose on your prescription or product label, and check with a pharmacist if you're unsure.
Can I drink alcohol with Levothyroxine?
Light alcohol use is generally tolerated with levothyroxine, but regular drinking can impair thyroid function and reduce medication effectiveness.
Is Levothyroxine safe to take during pregnancy?
Levothyroxine is safe and essential to continue in pregnancy — hypothyroidism must be well-controlled for healthy fetal development.
Is Levothyroxine available over the counter in the UK?
Levothyroxine is prescription-only in the UK.
What should I check before taking Levothyroxine with other medicines?
The interactions most often flagged for Levothyroxine are: iron, calcium, alcohol, pregnancy. Tell your pharmacist or prescriber about everything you take, including over-the-counter products, supplements and herbal remedies, before combining it with anything new.
What are the brand names for Levothyroxine?
Levothyroxine is sold under brand names including Synthroid, Eltroxin, Euthyrox. The active ingredient is the same, so check labels carefully to avoid doubling up on it.
Do I need a prescription for Levothyroxine?
Levothyroxine is a prescription medicine, so take it exactly as your prescriber directed and ask them before changing the dose.
Not sure if Levothyroxine is safe with your other medications?
HealthLabs.com lets you check liver enzyme or kidney function levels before combining medications long-term — no GP referral needed.
Check your levels at HealthLabs →Always speak to your pharmacist or GP for personalised medical advice. Affiliate link — we may earn a commission.