Can I take Magnesium and Flecainide together?

Why this happens

Both magnesium and flecainide affect the electrical signals and mineral channels (like sodium and potassium) in your heart cells. While they don't usually stop each other from being absorbed, having too much or too little magnesium in your blood can change how effective flecainide is at controlling your heart rhythm.

You can usually take these together, but do not start high-dose magnesium supplements without checking with your doctor first. Your doctor may want to monitor your blood mineral levels (electrolytes) to ensure flecainide works safely and effectively. If you feel any new heart palpitations, dizziness, or shortness of breath, contact your healthcare provider.

Heart conditions (structural or ischaemic heart disease)

Flecainide must not be used if you have had a heart attack or have structural heart disease (such as heart failure or heart valve problems), as it can increase the risk of life-threatening heart rhythm disturbances.

Permanent Atrial Fibrillation

Flecainide should not be used to treat long-term (permanent) atrial fibrillation, as it can potentially worsen the heart rhythm.

Kidney disease

If you have severe kidney problems, your body may not be able to remove excess magnesium, leading to dangerously high levels in the blood. Check with your doctor before use.

Alcohol

It is best to avoid or strictly limit alcohol while taking flecainide. Alcohol can trigger or worsen heart rhythm problems (arrhythmias), which is the condition flecainide is prescribed to treat. Combining them may also increase the risk of dizziness or lightheadedness.

It is best to avoid or strictly limit alcohol when taking magnesium. Alcohol acts as a diuretic, which can increase the amount of magnesium your body loses through urine, potentially making the supplement less effective. Additionally, chronic alcohol use can lead to magnesium deficiency.

Dairy products (Milk, Cheese, Yoghurt)

Avoid taking magnesium supplements at the same time as large amounts of dairy products. Dairy is high in calcium, and high doses of calcium can compete with magnesium for absorption in the gut, meaning you may not get the full benefit of your supplement. It is best to space them at least 2 hours apart.

In some cases, particularly in children or patients on a milk-based diet, high intake of milk can affect how flecainide is absorbed. However, for most adults, normal amounts of dairy are fine. If you are making a significant change to your dairy intake, discuss this with your doctor.

Caffeine (Coffee, Tea, Energy drinks)

You should limit your intake of caffeine. Caffeine is a stimulant that can increase your heart rate and may interfere with the effectiveness of flecainide in controlling your heart rhythm.

It is best to limit caffeine intake around the time you take magnesium. Like alcohol, caffeine has a mild diuretic effect and can increase the excretion of magnesium through the kidneys.

Low-salt (Low-sodium) diets

Do not make sudden, major changes to the amount of salt in your diet without speaking to your doctor. A significant decrease in salt intake can cause flecainide levels to rise in your blood, potentially increasing the risk of side effects.

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.