Can I take Flecainide and Wegovy together?
Drug interaction guide
Originally published 25 Jan 2026
Meets Patient’s editorial guidelines
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Wegovy (semaglutide) can slow down how quickly your stomach empties. This might change how your body absorbs flecainide, which is a medicine that needs to be kept at very specific levels in your blood to work safely and effectively. Additionally, both medications can occasionally affect your heart rhythm or heart rate.
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Why this happens
Wegovy is a GLP-1 receptor agonist that delays gastric emptying (the time it takes for food and pills to leave the stomach). This can delay or alter the absorption of oral medications like flecainide. Furthermore, semaglutide can sometimes increase resting heart rate, which may interact with the heart rhythm effects of flecainide.
What you should do
Back to contentsYou should speak to your doctor before using these together. Because flecainide has a 'narrow therapeutic index' (meaning the difference between a safe dose and a dangerous dose is small), your doctor may want to monitor your blood levels or perform an ECG (heart trace) more frequently when you start or change your dose of Wegovy. Contact your doctor immediately if you feel dizzy, faint, or notice a change in your heartbeat.
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Important precautions
Back to contentsHeart 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.
Pancreatitis
Stop using Wegovy and seek immediate medical help if you experience severe, persistent stomach pain which may reach through to your back, as this can be a sign of acute pancreatitis.
Dehydration
Nausea and vomiting can cause dehydration. Ensure you drink plenty of fluids to avoid kidney problems, especially when starting treatment or increasing your dose.
Food and drink warnings
Back to contentsAlcohol
It is best to avoid or strictly limit alcohol while taking flecainide. Alcohol can interfere with your heart rhythm and may increase the risk of side effects such as dizziness or blurred vision. Combining alcohol with heart medication can also put extra strain on your heart and liver.
It is best to avoid or strictly limit alcohol while taking Wegovy. Both alcohol and Wegovy can lower your blood sugar levels; combining them increases the risk of severe hypoglycaemia (dangerously low blood sugar). Additionally, alcohol can worsen common Wegovy side effects like nausea, vomiting, and dehydration.
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.
Large or high-fat meals
Wegovy slows down how quickly your stomach empties. Eating very large meals or foods high in fat can lead to severe nausea, bloating, and discomfort. It is recommended to eat smaller portions and stop eating as soon as you feel full.
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Using other medicines
Back to contentsTaking 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.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
25 Jan 2026 | Originally published
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