Can I take Levothyroxine and Sertraline together?

Why this happens

Sertraline can change how your body processes thyroid hormones. It may reduce the amount of free thyroid hormone available in your blood, meaning your current dose of levothyroxine might not be enough to keep your levels stable.

What you should do

You can take these medicines together, but you should tell your doctor if you are starting, stopping, or changing your dose of sertraline. Your doctor may want to perform a blood test to check your thyroid levels (TSH) a few weeks after starting sertraline to see if your levothyroxine dose needs to be adjusted.

Important precautions

Bleeding disorders or use of blood thinners

Sertraline can increase your risk of serious bleeding, especially if you already take medicines like aspirin, ibuprofen, or warfarin. Seek medical help if you notice unusual bruising or black, tarry stools.

Heart disease or angina

Levothyroxine puts extra strain on the heart. You must inform your doctor immediately if you experience chest pain, palpitations, or a rapid heartbeat, as your dose may need adjusting.

Taking indigestion remedies or iron/calcium supplements

These products stop levothyroxine from being absorbed. You must leave a gap of at least 4 hours between taking levothyroxine and any antacids, iron tablets, or calcium supplements.

Food and drink warnings

Coffee and Caffeine

Caffeine can significantly reduce the absorption of levothyroxine. You should wait at least 30 to 60 minutes after taking your tablet before drinking coffee or tea.

Dairy products (Milk, Yoghurt, Cheese)

Calcium found in dairy products can interfere with how your body absorbs levothyroxine. It is best to take your medicine on an empty stomach and wait at least 30 to 60 minutes before eating dairy.

Soya products

Soya can stop levothyroxine from being absorbed properly. If you eat a lot of soya, your doctor may need to monitor your hormone levels more closely.

Kelp and Seaweed

These are naturally high in iodine. Too much iodine can interfere with your thyroid treatment and make your condition worse.

High-fibre foods

A very high-fibre diet (such as lots of bran or beans) can reduce the absorption of levothyroxine. Try to keep your fibre intake consistent and talk to your doctor if you make big changes to your diet.

Alcohol

It is best to avoid alcohol while taking sertraline. Alcohol can increase the sedative effects of the medicine, making you feel more sleepy or unsteady.

Grapefruit juice

Grapefruit juice can increase the amount of sertraline in your bloodstream, which may increase the risk of side effects. It is best to avoid drinking large amounts of grapefruit juice.

Using other medicines

Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.