Can I take Lisinopril and Potassium together?

Why this happens

Lisinopril is an ACE inhibitor used for blood pressure. One of its side effects is that it tells the kidneys to hold onto potassium rather than flushing it out in your urine. If you take extra potassium (as a supplement or salt substitute) while the lisinopril is already keeping your levels high, the potassium builds up in your bloodstream.

What you should do

Do not take potassium supplements or use 'low-sodium' salt substitutes (which are often made of potassium) while taking lisinopril unless your doctor has specifically told you to. Your doctor will perform regular blood tests to monitor your potassium levels. If you experience an irregular heartbeat, severe tiredness, or muscle weakness, seek medical advice immediately.

Important precautions

Pregnancy

You must not take lisinopril if you are pregnant or planning to become pregnant, as it can cause serious harm or death to an unborn baby, particularly in the second and third trimesters.

Hyperkalaemia (High Potassium)

Taking these two medicines together significantly increases the risk of dangerously high potassium levels in your blood. You must have regular blood tests to monitor your potassium and kidney function.

Angioedema (Severe Swelling)

Seek emergency medical help immediately if you experience swelling of the face, lips, tongue, or throat, as lisinopril can cause a life-threatening allergic reaction called angioedema.

Stomach or intestinal blockages

Potassium tablets can cause severe irritation or ulcers in the digestive tract; they must be taken with a full glass of water and you should avoid lying down for at least 30 minutes after taking them.

Food and drink warnings

Salt substitutes and low-sodium salts (e.g., LoSalt)

These products often contain potassium chloride. Taking them alongside lisinopril or potassium supplements can cause your blood potassium levels to become dangerously high (hyperkalaemia).

High-potassium foods (e.g., bananas, spinach, avocados)

Lisinopril makes your body retain potassium. If you are also taking a potassium supplement, you should avoid eating large amounts of potassium-rich foods unless specifically advised by your doctor, as this can lead to heart rhythm problems.

Alcohol

It is best to avoid or strictly limit alcohol while taking these medicines. Alcohol can increase the blood-pressure-lowering effect of lisinopril, which may make you feel dizzy, lightheaded, or faint, especially when you stand up. Additionally, heavy alcohol use can affect your body's potassium balance and increase the risk of kidney issues when combined with these treatments.

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.