Can I take Digoxin and Liquorice together?

Why this happens

Liquorice contains a substance called glycyrrhizic acid. This causes the kidneys to flush potassium out of the body. Digoxin is very sensitive to potassium levels; when potassium is low, digoxin binds more strongly to the heart muscle, leading to digoxin poisoning (toxicity).

What you should do

You should strictly avoid eating natural black liquorice or taking liquorice root supplements while taking digoxin. Check food labels for 'liquorice extract' or 'glycyrrhizic acid'. Most 'liquorice-flavoured' sweets in the UK use anise oil for flavouring and are safe, but you must confirm they do not contain real liquorice extract. If you feel sick, have a blurred yellow-green tint to your vision, or feel your heart racing or skipping beats, contact a doctor immediately.

Important precautions

Low potassium (Hypokalaemia)

Liquorice (especially natural black liquorice) can cause your body to lose potassium. Low potassium levels significantly increase the risk of digoxin toxicity, which can cause serious heart rhythm problems. Avoid consuming large amounts of liquorice while taking digoxin.

Kidney problems

If your kidneys are not working properly, digoxin can build up to dangerous levels in your body. Your doctor must monitor your kidney function closely.

Digoxin toxicity symptoms

You must watch for signs that your dose is too high, such as blurred or yellow-green vision, loss of appetite, or a very slow/irregular heartbeat. Contact a doctor immediately if these occur.

Food and drink warnings

Alcohol

It is best to avoid or strictly limit alcohol while taking digoxin. Alcohol can worsen heart conditions and may increase the risk of side effects like dizziness or confusion.

It is best to avoid or strictly limit alcohol when using liquorice medicinally. Both substances can affect your blood pressure and electrolyte balance, and combining them may increase the risk of headaches or fluid retention.

Natural black liquorice

Avoid eating large amounts of natural black liquorice. It can cause your body to lose potassium, which increases the risk of digoxin toxicity (serious side effects). This applies to the root extract, not most liquorice-flavoured sweets.

High-fibre foods (e.g., wheat bran)

Eating very large amounts of fibre at the same time as taking your tablet can reduce the amount of digoxin absorbed by your body. Try to take your medicine at least 2 hours before or after eating high-fibre foods.

Salt (Sodium)

Liquorice can cause your body to hold onto salt and water while losing potassium. Eating a diet high in salt while taking liquorice supplements or eating large amounts of natural liquorice can worsen high blood pressure and fluid retention (oedema).

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.