Sounds like 'flek-ah-nide'

Flecainide is used to treat irregular heartbeat (also called arrhythmias). Find out how to take it safely and possible side effects. Flecainide is also called Tambocor CR.

Type of medicine Also called
  • For irregular heartbeat
  • Flecainide (Teva)
  • Tambocor CR
  • Arrow-Flecainide
As of 1 July 2019, the brand of flecainide capsules called Tambocor CR will be replaced by a brand called Flecainide Controlled Release Teva. Read more.

What is flecainide?

Flecainide is used to treat irregular heartbeat (also called arrhythmias). An irregularity in your heartbeat can cause your heart to skip a beat, beat unevenly or beat very fast or very slowly. Arrhythmias can put you at risk of a heart attack or stroke. 

In New Zealand, flecainide is available as immediate-release tablets (50 mg) and slow-release capsules (100 mg and 200 mg) and as an injection that is used in hospitals.


  • The dose of flecainide will be different for different people.
  • Your doctor will usually start you on a low dose and increase it slowly over a few days.
  • Always take your flecainide exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it, and any special instructions.

How to take flecainide

Flecainide is available in 2 forms, as immediate-release tablets and slow-release capsules. Check with your pharmacist which form you are taking.

Formulation How to take it
Immediate release tablets 
  • These are taken two times a day.
  • Try to take your doses around the same times each day. 
  • Do not crush or chew the tablets.
Slow release capsules  
  • These are taken once a day.
  • Try to take your dose around the same time each day.
  • Do not open the capsules, or crush or chew them.
  • You can take flecainide with or without food.
  • If you forget to take your dose, take it as soon as you remember. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose. Do not stop taking flecainide suddenly – this can make your condition worse.
  • If your tablets or capsules look different to your last supply speak with your doctor or pharmacist for advice.

Precautions before taking flecainide

  • Are you pregnant, planning a pregnancy or breastfeeding?
  • Do you have problems with your kidneys or liver?
  • Have you had a heart attack?
  • Do you have a pacemaker?
  • Do you have heart failure?
  • Are you are taking or using any other medicines? This includes any medicines you are using that are available to buy from a pharmacy, supermarket or natural health store without a prescription.

If so, it’s important that you tell your doctor or pharmacist before you start taking flecainide. Sometimes a medicine isn’t suitable for a person with certain conditions or it can only be used with extra care.

What are the side effects of flecainide?

Like all medicines, flecainide can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Dizziness
  • Feeling lightheaded
  • Tiredness
  • Confusion
  • This is quite common when you first start taking flecainide and usually goes away with time.
  • Avoid alcohol.
  • Do not drive and do not use tools or machines.
  • Tell your doctor if this continues.
  • Problems sleeping
  • Loss of appetite
  • Nausea (feeling sick)
  • Headache
  • Tell your doctor if troublesome.
  • Changes in your heart beat (either fast, slow or irregular)
  • Blurred eyesight, double vision, cannot stand bright lights
  • Tell your doctor immediately or ring HealthLine 0800 611 116.
  • Chest pain
  • Rash
  • Problems breathing
  • Tell your doctor immediately or ring HealthLine 0800 611 116.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product


Flecainide may interact with a few medications and herbal supplements so check with your doctor or pharmacist before starting flecainide or before starting any new medicines.

Learn more

The following links have more information on flecainide.

Flecainide New Zealand Formulary Patient Information


  1. Flecainide New Zealand Formulary

Additional resources for healthcare professionals

Flecainide controlled release (Teva) Medsafe, NZ
TAMBOCOR tablets Medsafe, NZ
Antiarrhythmic medicine brand changes – flecainide and amiodarone BPAC, NZ, 2019
An update on managing patients with atrial fibrillation BPAC, NZ, 2017

Credits: Sandra Ponen, pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 20 Jul 2019