Can I take Levothyroxine and Felodipine together?

Why this happens

Levothyroxine is a thyroid hormone, and felodipine is a calcium channel blocker used for high blood pressure. Thyroid hormones affect your metabolism. If you are hyperthyroid (too much hormone) or hypothyroid (too little), your body may break down felodipine faster or slower than usual, which could make the blood pressure medicine more or less effective.

You can take these medicines together. However, if your doctor changes your levothyroxine dose, you should monitor your blood pressure more closely. If you feel dizzy, get a headache, or notice your heart racing, contact your doctor. Always leave a gap of at least 30 to 60 minutes between taking your levothyroxine (usually on an empty stomach) and any other medications or food.

Heart conditions (e.g. angina, heart failure)

If you have a heart condition, your dose must be started very low and increased slowly. Contact your doctor immediately if you experience chest pain or palpitations, as levothyroxine increases the workload on your heart.

Interaction with supplements (Calcium/Iron)

Do not take calcium tablets, iron supplements, or multivitamins at the same time as levothyroxine. You must leave a gap of at least 4 hours between these supplements and your levothyroxine to ensure the medicine works.

Diabetes

Levothyroxine can raise blood sugar levels. If you have diabetes, you must monitor your blood glucose more closely when starting or changing your dose, as your diabetes medication may need to be increased.

Grapefruit juice consumption

Do not drink grapefruit juice or eat grapefruit. It can significantly increase the level of felodipine in your blood, leading to a dangerous drop in blood pressure and an increased risk of side effects.

Alcohol

It is best to avoid or strictly limit alcohol while taking these medicines. For felodipine, alcohol can increase the blood-pressure-lowering effect, making you feel dizzy or faint. For levothyroxine, alcohol can interfere with how your body processes the hormone and may worsen symptoms. Combining alcohol with many medicines also increases the risk of liver strain.

Timing of dose and food/drink

Take your levothyroxine on an empty stomach, at least 30 to 60 minutes before breakfast or any caffeine. Food, milk, and coffee prevent the medicine from being absorbed properly.

Caffeine (Coffee/Tea)

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

Dairy products (Milk, Yoghurt, Cheese)

Avoid consuming dairy products at the same time as your levothyroxine. Calcium found in dairy can interfere with how your body absorbs the medicine, making it less effective. It is best to wait at least 4 hours between taking levothyroxine and consuming dairy.

Soya products

Soya can interfere with the absorption of levothyroxine. If you regularly eat or drink soya products, your doctor may need to monitor your thyroid levels more closely. Avoid consuming soya at the same time as your dose.

Kelp and Seaweed

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

High-fibre foods

A diet very high in fibre can reduce the absorption of levothyroxine. If you significantly change your fibre intake, inform your doctor as your dose may need adjusting.

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.