Levothyroxine Drug Interactions
Levothyroxine can interact with prescription medications, over-the-counter products, supplements, and certain foods. Most interactions are manageable when your pharmacist knows your full medication list.
Common interaction categories to flag with your pharmacist
Other prescription medications
Bring a current list of every prescription you take when filling Levothyroxine. Common interactions involve blood thinners, antibiotics, antidepressants, and pain medications.
Over-the-counter products
OTC products like NSAIDs, antacids, cold/flu remedies, and sleep aids can interact with Levothyroxine. Confirm with your pharmacist before combining.
Supplements and herbal products
Common offenders include St John's wort, garlic, ginkgo, high-dose vitamins, and mineral supplements. Disclose all supplements when filling Levothyroxine.
Foods and beverages
Grapefruit, leafy greens (vitamin K), tyramine-rich foods, and others can interact with specific medications. Ask whether any apply to Levothyroxine.
Alcohol
Alcohol interacts with many medications, sometimes seriously. See our dedicated Levothyroxine and alcohol guide.
Caffeine and stimulants
Caffeine, energy drinks, and other stimulants can interact with some Levothyroxine use cases. Check with your pharmacist if you consume regularly.
How to check $Levothyroxine interactions safely
- Give your pharmacist a complete list of everything you take — prescription, OTC, supplements, herbal.
- Update your pharmacy profile whenever you start or stop a medication.
- Use a single pharmacy when possible — the pharmacist's system flags interactions automatically.
- Read the patient information leaflet that comes with Levothyroxine.
- Call your pharmacist before starting any new product — they're trained interaction specialists.
Symptoms that suggest an interaction
Unusual drowsiness, rapid heart rate, blood pressure changes, severe GI symptoms, unusual bleeding, or any reaction that feels new — call your pharmacist or prescriber immediately.
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Levothyroxine interactions: FAQs
What medications interact with Levothyroxine?
Levothyroxine can interact with many prescription medications, OTC products, supplements, and herbal remedies. Before starting Levothyroxine, give your pharmacist a complete list of everything you take — they'll flag any clinically significant interactions.
Can I take Levothyroxine with over-the-counter medications?
Some OTC medications interact with Levothyroxine and others don't. Common ones to ask about: NSAIDs, antacids, cold/flu products, and any sleep aids. Confirm with your pharmacist before combining.
Are there supplements I should avoid while taking Levothyroxine?
Supplements and herbal products can interact with Levothyroxine — common examples include St John's wort, grapefruit-related products, and high-dose vitamins. Always disclose supplements to your pharmacist.
What should I do if I've started a new medication and I'm on Levothyroxine?
Whenever you start any new prescription, OTC, or supplement, mention Levothyroxine to the prescriber or pharmacist. Most interactions are manageable with timing changes or dose adjustments.
Where do I find the lowest cash price for Levothyroxine?
Compare cash prices across local pharmacies before filling. ScriptUnlock surfaces the lowest available for Levothyroxine among participating pharmacies.