Sounds like 'flek-ah-nide'

Key points about flecainide

  • Flecainide is used to treat irregular heartbeat (also called arrhythmia).
  • Flecainide is also called Tambocor CR® and Flecatab®.
  • Find out how to take it safely and possible side effects.
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Flecainide is used to treat irregular heartbeat (also called arrhythmia). 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 Aotearoa New Zealand, flecainide is available as:

  • immediate–release tablets (50 mg and 100 mg)
  • slow–release capsules (100 mg and 200 mg) 
  • oral liquid (20 mg in 1 ml and 25 mg in 5 ml)
  • an injection that's used in hospitals.

Flecainide is available as immediate–release tablets and slow–release capsules. Check with your pharmacist which kind you are taking.

Formulation How to take it
Immediate release tablets 
  • These are taken 2 times a day.
  • Try to take your doses around the same times each day. 
  • Don't 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.
  • Don't open the capsules, or crush or chew them.


  • Food: You can take flecainide with or without food.
  • Missed dose: If you forget to take your dose, take it as soon as you remember. But if it's nearly time for your next dose, just take the next dose at the right time. Don't take double the dose. 

Here are some things to know when you're taking flecainide. Other things may be important as well, so ask your healthcare provider what you should know about.

  • Other medicines: flecainide interacts with some medicines, herbal supplements and Rongoā Māori, so check with your doctor or pharmacist before starting flecainide and before starting any new products.
  • Driving: Be careful when driving or using tools until you know how this medicine affects you.
  • Keep taking flecainide regularly: Don’t stop taking flecainide suddenly – this can make your condition worse. 
  • Check what they look like: If your tablets or capsules look different to your last supply, contact your doctor or pharmacist for advice.
  • Let healthcare providers know you're taking it: Tell any other healthcare providers including dentists who are treating you that you are taking flecainide.
  • Surgery: If you're going to have surgery, tell the surgeon or anaesthetist that you are taking this medicine. It may affect other medicines used during surgery.
  • Smoking: Smoking can change the effect of flecainide. Tell your doctor if you give up, cut down or start smoking.
  • Pregnant: If you become pregnant while taking or being given this medicine, tell your doctor immediately
  • Pregnancy or breastfeeding: talk to your doctor if you're planning to become pregnant or breastfeed.

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
  • Tiredness
  • Blurred eyesight, double vision, cannot stand bright lights
  • These are quite common when you first start taking flecainide and usually go away with time.
  • Avoid alcohol.
  • Don't drive and don't use tools or machines.
  • Tell your doctor if any of these continue or bother you.
  • Nausea (feeling sick)
  • Headache
  • Swollen hands or feet
  • These are quite common.
  • Tell your doctor if these bother you.
  • Changes in your heart beat (either fast, slow or irregular)
  • Chest pain
  • You feel short of breath
  • Fainting
  • These are less common.
  • Tell your doctor immediately or ring Healthline 0800 611 116.
  • Rash
  • Problems breathing
  • These are rare but serious. 
  • Tell your doctor immediately or ring Healthline 0800 611 116.

Read more about medicines and side effects and reporting a reaction that you think might be a side effect.

The following links have more information on flecainide.

Flecainide(external link) New Zealand Formulary Patient Information
Tambocor(external link) Medsafe Consumer Medicine Information, NZ


  1. Flecainide(external link) New Zealand Formulary
  2. Flecainide(external link) Medsafe Data sheet, NZ

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Stephanie Yee, Pharmacist, Auckland

Last reviewed: