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Can I take Cod liver oil and Eplerenone together?

Drug interaction guide

Taking cod liver oil and eplerenone together may slightly increase the risk of your blood pressure dropping too low or may affect your potassium levels, though the risk is generally low.

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Why this happens

Cod liver oil contains omega-3 fatty acids, which have a mild blood-pressure-lowering effect. Eplerenone is a medicine specifically designed to lower blood pressure and remove excess fluid. When used together, their effects can add up. Additionally, while rare, high doses of fish oils can sometimes influence how the kidneys handle minerals like potassium, which eplerenone also affects.

You can usually take these together, but it is a good idea to inform your doctor or pharmacist. If you feel dizzy, lightheaded, or faint (especially when standing up), let your healthcare provider know. Do not exceed the recommended daily dose of cod liver oil.

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High potassium levels (hyperkalaemia)

Eplerenone can cause dangerously high potassium levels. You must avoid potassium supplements and salt substitutes containing potassium (such as Lo-Salt), as these can lead to life-threatening heart rhythm problems.

Pregnancy

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.

Kidney disease

You must not take eplerenone if you have severe kidney disease, as this significantly increases the risk of life-threatening potassium build-up.

Grapefruit juice

Avoid drinking large amounts of grapefruit juice. Grapefruit can increase the level of eplerenone in your blood, which increases the risk of side effects.

Alcohol

It is best to avoid or strictly limit alcohol while taking eplerenone. Alcohol can increase the blood-pressure-lowering effect of the medicine, which may make you feel dizzy, lightheaded, or faint.

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.

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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.

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Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • 25 Jan 2026 | Originally published
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