Can I take Flecainide and Tamsulosin together?

Why this happens

Both drugs are processed by the same enzyme in the liver (CYP2D6). Flecainide can slow down this enzyme, which prevents tamsulosin from being broken down as quickly as usual, leading to higher levels of the drug in your system.

What you should do

You can take these medicines together, but you should be cautious. Monitor your blood pressure and watch for signs of dizziness, especially when moving from a sitting or lying position to standing. If you feel very dizzy or faint, contact your doctor, as they may need to adjust your tamsulosin dose.

Important precautions

Heart failure or previous heart attack

Flecainide must not be used if you have heart failure or have previously suffered a heart attack, as it can increase the risk of life-threatening heart rhythm problems.

Permanent atrial fibrillation

This medicine should not be used if you have long-standing (permanent) atrial fibrillation that has not been corrected, as it can paradoxically cause the heart rate to become dangerously fast.

Cataract or glaucoma surgery

If you are scheduled for eye surgery, you must tell your surgeon you are taking tamsulosin. It can cause 'Floppy Iris Syndrome', which may lead to serious surgical complications if the surgeon is not prepared.

Postural hypotension (dizziness when standing)

Tamsulosin can cause a sudden drop in blood pressure when you stand up, especially after the first dose. Take care when moving from lying to standing to avoid fainting or falls.

Food and drink warnings

Alcohol

It is best to avoid or strictly limit alcohol while taking these medicines. Alcohol can increase the blood-pressure-lowering effect of tamsulosin, making you feel dizzy or faint. For flecainide, alcohol can interfere with heart rhythms and increase the risk of side effects.

Caffeine (Coffee, tea, energy drinks, cola)

Caffeine is a stimulant that can increase your heart rate or cause irregular heart rhythms. Since flecainide is used to treat heart rhythm problems (arrhythmias), consuming high amounts of caffeine may counteract the effects of your medicine or make your condition worse. It is best to limit your intake of caffeine.

Dairy products (Milk)

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.

Low-salt (low-sodium) diets

A sudden change to a very low-salt diet or using salt substitutes can increase the levels of flecainide in your blood, which may lead to toxicity. Do not make major changes to your salt intake without consulting your doctor.

Food (Timing)

Tamsulosin should be taken at the same time each day, usually after breakfast or the first meal of the day. Taking it on an empty stomach can increase the amount of medicine absorbed too quickly, which increases the risk of dizziness and low blood pressure.

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.