Can I take Cod liver oil and Losartan together?

Why this happens

Losartan is a medicine prescribed specifically to lower blood pressure. Cod liver oil contains omega-3 fatty acids, which have a natural, mild blood-pressure-lowering effect. When used together, these effects can add up (an additive effect), resulting in lower blood pressure readings than when taking losartan alone.

What you should do

It is generally safe to take both, but you should monitor your blood pressure more closely when starting cod liver oil or changing your dose. If you feel dizzy or lightheaded, sit or lie down until the feeling passes, and speak to your doctor. They may wish to adjust your losartan dose if your blood pressure becomes too low.

Important precautions

Pregnancy (Vitamin A toxicity)

You must not take losartan if you are pregnant or planning to become pregnant, as it can cause serious harm or death to an unborn baby. Use effective contraception while taking this medicine.

Do not take cod liver oil if you are pregnant or planning to become pregnant. It contains high levels of Vitamin A (retinol), which can harm the development of an unborn baby.

High potassium levels (Hyperkalaemia)

Losartan can increase potassium levels in your blood. Avoid using salt substitutes containing potassium and be cautious with potassium supplements, as high levels can affect your heart rhythm.

Food and drink warnings

Alcohol

Drinking alcohol while taking losartan can increase the blood-pressure-lowering effect of the medicine. This may make you feel dizzy, lightheaded, or faint, especially when standing up from a sitting or lying position. It is best to keep your alcohol intake within recommended limits and see how the medicine affects you before drinking.

It is best to avoid or strictly limit alcohol when taking cod liver oil. Both alcohol and high doses of vitamin A (found in cod liver oil) can put strain on the liver; combining them may increase the risk of liver toxicity.

Potassium-rich foods and salt substitutes

Losartan can increase the levels of potassium in your blood. You should avoid using salt substitutes that contain potassium (often labelled as 'low sodium' salts) and speak to your doctor before significantly increasing your intake of potassium-rich foods (such as bananas, spinach, or sweet potatoes), as very high potassium levels can be dangerous.

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.