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AF Association
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Flecanide, how can it be dangerous long term

Hi. I have had afib 14 years, 3 ablations , various meds. I have been on Flecanide for 3 years, then off it for 3 years until sept, now on 2x 100 per day= 200.

I have read on this forum that it can be dangerous long term. Exactly what does it or can do to some of us long term and what is considered long term. Toxic to the liver? Toxic to kidneys? Hard on heart muscles? Without it, I would be in afib almost every day. With it, I now only get a very few ectopic ocassionaly, not even every day, this is the best I have felt in 14 years. ( not to mention I had my last ablation aug 30)

Ep said he wasn’t,t very optimistic this time, hey doc ,this is the best you have done as far as I am feeling. I am on xeralto also. ( that has always worried me as I had near death brain aneurysm in 2003)

Love this forum, I read it every day, just to hear the good supporting words from all of you. Thanks Marney

5 Replies

Oh Marney. I only take it as a PIP (pill in the pocket when needed) but I am sure someone who has been on it daily will chime in soon. All medication is about Risk management as it seems and everything has some risk and possible side effects. Good luck


I have been taking Flecainide for more than 20 years.

I am currently being weaned off it as I have been suffering from acute nausea and my EP thinks that there MAY be a connection.

That, as far as I am aware is the only issue for me.

If you are finding it is helping your AF keep taking the tablets.



Flecainide is a sodium channel blocker. Does anyone know how this is affected by my salt intake?

We hear a lot about calcium channel blockers as replacements for beta blockers. One of those gave me swollen ankles. I haven't recognised any side effects from flecainide


Really hard to quantify - for me this drug is dangerous & can no longer take it.

There are risks short term and long term with this drug - I know my EP always monitored me for long QT and other Arrythmias as it can cause ventricular Arrythmia - need to be regularly monitored for liver function - when on Flec this was every 6 months. I think how you react to a drug is very individual - one man’s meat is another’s poison.

Unfortunately it can be a bit late if it proves to be poison.

I don’t take any drugs for AF other than anticoagulant which I do NOT worry about having recently had a TIA.

Risk:Benefit is individual.

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I found an article which I shall post a link to for the nerds later but for you the important conclusion is that Flecainide taken regularly can partly reverse the remodeling of the heart caused by AF, so sounds good! No mention of adverse effects long-term.

Glad you are feeling better!


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