Can I take Losartan and Magnesium together?

Why this happens

Both losartan and magnesium can lower blood pressure. When used together, their effects can add up, potentially making your blood pressure drop lower than intended. Furthermore, losartan causes the body to hold onto potassium; while magnesium is generally safe, some magnesium formulations or kidney issues can lead to an imbalance of salts (electrolytes) in the blood.

What you should do

You can usually take these together, but you should monitor your blood pressure regularly. If you feel dizzy, lightheaded, or faint—especially when standing up—speak to your doctor. It is best to space the doses out by at least 2 hours if you are taking a high-dose magnesium supplement to ensure it doesn't interfere with how the medicine is absorbed. Always inform your doctor if you are taking magnesium, as they may want to check your kidney function and potassium levels.

Important precautions

Pregnancy

You must not take this medicine 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.

Kidney disease

If you have kidney problems, taking these together can cause your potassium or magnesium levels to become dangerously high. Your doctor must monitor your blood levels closely.

Food and drink warnings

Potassium-rich foods (e.g., bananas, spinach, avocados) and salt substitutes

Losartan can increase the levels of potassium in your blood. Consuming large amounts of potassium-rich foods or using salt substitutes containing potassium can lead to dangerously high potassium levels (hyperkalaemia).

Alcohol

Alcohol can increase the blood-pressure-lowering effect of losartan, which may make you feel dizzy or light-headed. For magnesium, excessive alcohol can increase the amount of magnesium lost through urine, potentially making the supplement less effective.

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.