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Terms Of Use


Brand Name(s) : Tambocor, Tambocor XL
Side Effects


Flecainide acetate should be used with caution in:

It should not be used in:

  • people who are allergic (hypersensitive) to flecainide acetate, or any other ingredients in the medication, people who suffer from conduction problems of the heart leading to slow or fast heart beat or heart block, those who have had heart failure, patients who have had a heart attack (myocardial infarction), those in shock due to a heart disorder (cardiogenic shock), people who have rapid and irregular heart beat (atrial fibrillation) that is long-standing and has not been corrected, or people taking disopyramide (another medicine for irregular heart rhythms).

Also see list of precautions and interactions.


Store below 25°C and keep container in its outer carton.


What is it used for?

  • Flecainide acetate is used to treat certain types of irregular heartbeats (arrhythmias). It is an anti-arrhythmic.
  • In general, it is used to regulate heartbeats of the upper heart and lower heart chambers. It can also be used to slow down an overactive heart. Sometimes, it may be used to maintain a regular heartbeat after initial correction by other treatments.
  • Benefits of being on this drug can include a more regular heart rhythm and reduced likelihood of arrhythmias.

Listed below are typical uses of flecainide acetate:

  • To correct irregular beats of the upper heart chambers (atria), such as Wolff-Parkinson-White Syndrome
  • To correct irregular beats of the lower heart chambers (ventricles)
  • To treat ventricular tachycardia, an unusually fast beat of the ventricles
  • To treat atrial fibrillation. In this condition, the electrical impulses that regulate the heartbeat fire randomly, causing the heart chambers to contract rapidly, partially and irregularly


How often do I take it?

  • Take this medication exactly as directed by your doctor. Some brands of flecainide acetate tablets may need to be swallowed whole with water one hour before food.
  • Use flecainide acetate for the full duration of the prescription in order to get the most benefit from it.
  • Remember to use it at the same time each day - unless specifically told otherwise by your doctor.
  • Certain medical conditions may require different dosage instructions as directed by your doctor.
  • It is recommended that intravenous treatment with flecainide acetate should take place in hospitals.

What dose?

  • Dosage is based on your age, gender, medical condition, response to therapy, and use of certain interacting medicines.

Do I need to avoid anything?

  • Some formulations of flecainide acetate may cause dizziness or affect your vision. Make sure you are not affected before you drive or operate machinery. Consult your doctor or pharmacist for more details.

When can I stop?

  • It is important to continue taking this medication even if you feel well, unless your doctor tells you to stop.


  • Dizziness
  • Light headedness
  • Headache
  • Blurred or double vision
  • A worsening of your heart condition
  • Development of new heart symptoms
  • A change in heart rhythm (especially in patients with existing heart problems)
  • Changes in the numbers and types of blood cells (leucopoenia)
  • Breathing difficulties
  • Nausea
  • Vomiting
  • Changes in immune system function that may be associated with inflammation
  • Hallucinations
  • Depression
  • Confusion
  • Memory loss
  • Nervousness
  • Anxiety
  • Disturbances in movement
  • Convulsions
  • ‘Pins and needles’ or numbness
  • Co-ordination problems
  • Raised liver enzyme levels
  • Jaundice (yellow skin and/or eyes)
  • Deposits on the front of the eye (corneal deposits)
  • Lung disease (pneumonitis)
  • Skin sensitivity to light
  • Flushing
  • Increased sweating
  • Allergic skin reactions (which may cause itchiness)
  • Dry mouth
  • Inability to taste properly
  • Joint and muscle pain
  • Impotence

If any of these persist or you consider them severe then inform doctor or pharmacist.

Stop taking flecainide acetate and tell your doctor immediately if you develop any of the following symptoms:

  • skin rash, swelling of the face, lips, tongue or throat, or difficulty breathing or swallowing.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

The Yellow Card Scheme allows you to report suspected side effects from any type of medicine (which includes vaccines, herbals and over the counter medicines) that you are taking. It is run by the medicines safety watchdog called the Medicines and Healthcare products Regulatory agency (MHRA). Please report any suspected side effect on the Yellow Card Scheme website.


Before taking flecainide acetate tell your doctor or pharmacist if you are allergic to it; or to other anti-arrhythmics; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist in case of:

  • conduction problems of the heart, leading to slow or fast heart beat or heart block, heart failure, had a heart attack (myocardial infarction), shock due to a heart disorder (cardiogenic shock), and long-standing rapid and irregular heart beat (atrial fibrillation) that has not been corrected.

Before using this medication, tell your doctor or pharmacist your medical history, especially any of the following:

  • Low or high blood potassium levels, liver or kidney disease, whether you have a pacemaker, heart disease, an enlarged heart, rapid or irregular heart beats after heart surgery, sick sinus syndrome (a condition in which the heart's rhythm is disturbed), or if you are pregnant or breast-feeding.

Before having surgery, tell your doctor or dentist that you are taking this medication.

Does alcohol intake affect this drug?

  • Alcohol intake does not appear to affect this drug.

The elderly: flecainide acetate may be given to elderly patients.

Pregnancy and breastfeeding - please ensure you read the detailed information below


The safety of flecainide acetate has not been established during pregnancy. Ask your doctor or pharmacist if you have any doubts or questions about this.

It is sensible to limit use of medication during pregnancy whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Flecainide acetate is not suitable to take if you are breastfeeding. Ask your doctor or pharmacist if you have any doubts or questions about this.

It is sensible to limit use of medication during breastfeeding whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first.

This drug should not be used with the following medications because very serious, possibly fatal interactions may occur:

  • disopyramide for arrhythmias (irregular heart rhythms)

If you are currently using any of these medications, tell your doctor or pharmacist before starting flecainide acetate:

  • verapamil or beta-blockers (such as propranolol for high blood pressure)
  • laxatives (for constipation)
  • diuretics (also known as ‘water tablets’)
  • steroids (such as hydrocortisone or prednisolone)
  • sodium channel blockers (such as lidocaine arrhythmias or as a local anaesthetic)
  • phenytoin, phenobarbital or carbamazepine (for epilepsy)
  • digoxin (for heart conditions)
  • amiodarone, quinidine or disopyramide (for arrhythmias)
  • cimetidine (for stomach ulcers)
  • fluoxetine (for depression)
  • tricyclic antidepressants (such as amitriptyline to treat depression)
  • terfenadine or astemizole (for allergic reactions)
  • quinine or halofantrine (to treat or prevent malaria)
  • Antivirals e.g. indinavir, saquinavir, ritonavir

This information does not contain all possible interactions. Therefore, before using flecainide acetate, tell your doctor or pharmacist of all the products you use.


Taking too much flecainide acetate could cause a potentially life-threatening medical emergency.

If you think you, or someone you care for, might have accidentally taken more than the recommended dose of flecainide acetate or intentional overdose is suspected, contact your local hospital, GP or if in England call 111. In Scotland call NHS 24. In Wales, call NHS Direct Wales. In the case of medical emergencies, always dial 999.


If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

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Source: Selected from data included with permission and copyrighted by Boots UK Limited. This copyrighted material is sourced from a licensed data provider and is not for distribution, except as may be authorised by the applicable terms of use.
CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgement of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse events, nor should it be construed to indicate that use of a particular medicine is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any medicine, changing any diet, or discontinuing any course of treatment.

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