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Flecainide side effects

Hi there, My husband took flecainide 300mg yesterday with 5mg bisoprolol to regulate his AF (he only uses it when he has an attack) and it made him feel quite ill, dizzy, nauseous etc. The last time he took it about 5 months ago he ended up in hospital as he had a fit, vomited and passed out, his blood pressure was very low and they had difficulty finding a pulse. His consultant said to try it again (as long as he had someone with him) and see what happened. He took this at work and once again felt ill after about an hour so his colleague took him to casualty (he works away from home so couldn't be left alone in his flat), he was there for a couple of hours, blood pressure a little high when he got there , ecg was fine and it did stop the AF. I know that his symptoms are listed in the side effects so is this normal to feel so ill when taking flecainide? I think because of his previous experience with it and the fact that he's been told not to take when alone it's all a bit worrying. Any help would be appreciated as he's unsure whether or not to take it again, he will of course contact his consultant but just wondered if others had experienced this.

13 Replies

Hi I have been on Flecainide for about 5 years, I used to use the pill in the pocket approach taking 300 mg on onset of an episode of AF. The first time I took it was under medical supervision - that is the recommendation - and I was warned that it may induce nausea. I did experience slight nausea but it was tolerable. After that what I discovered was that I only felt ill when I took Flec with food or had eaten within 1 hour of taking or ate within one hour. Otherwise I had no major side-affects once I aclimatised to the drug. AFib makes me feel dizzy and faint and very occasionally I black out for seconds, but that is the AFib not the Flec. The Flec takes at least 1 hour to be affective and often much longer, up to 3 hours so it is difficult to determine what is the affect of the drug and the symptoms of the AFib. I use self monitoring so that I know.

Having had an ablation I am now on 100mg x 2 daily Flec whilst I recover and it makes me tired. Another affect is that I want to eat more, I always got the munchies after taking the 300mg dose about 4-5 hours after taking it.

Everyone tolerates different drugs very differently but sounds as though he should return to the GP and request another consultation with the EP if he can't tolerate the Flecainide, as many people on this site can't.

It is often worrying for the partners of AFib witnessing the episodes, I think I'd rather have it myself than have my loved one suffer! How does your husband cope with illness?


He's okay with it, he doesn't have too many episodes of AFib which he's had for 30 years but they are increasing in regularity and intensity. He's recently postponed an ablation and hopes to manage his symptoms until he retires in 3 years and then have the procedure. He also has a PFO (hole in the heart) and septal aneurysm which were only discovered when he had an echo last year. We've been told by a cardiologist doing research into AFib that weight might play a bigger part than previously thought. Although hubby's not very overweight he's slimming down and eating more healthily as well as watching alcohol intake in the hope that this might help for the next few years at least. Thanks for you help CDreamer


Having had the ablation, I am 62, which was MUCH, MUCH easier than I ever imagined, my advice would be go for the ablation ASAP. I hope to be free of drugs in the near future having had the ablation at end of November. There is a saying on this site that AFib begets Afib, the advice at the patient day was that the longer the delay, the less likelihood of success. Par AFib will turn into persistant AFib which is much harder to treat by ablation.

I have a PFO, which was not picked up on either an echocardiogram nor a TOE (echocardiogram taken from the osoephogus) as well and actually this made the ablation simpler as they go in through the right atria and need to punch a hole through the septal in order to get into the left atria which is where the ablation to stop the AFib. The ablation was an overnight stay and advised to take it very easy for 2 weeks, mainly to allow the veins to heal as a bleed could be serious. I got into a car to go home less than 24 hours after the procedure and although I didn't drive, travelled from central London to Devon. The technology was amazing and apart from some very minor discomfort the day after I have been pain free. I have had one serious episode +5 days after the procedure, 30 hours of tachycardia which resolved without treatment at +3weeks, 1 minor episode which lasted 5 mins. You are warned that it takes 3 months for scar tissue to form, which provides the barrier to the rogue electric short circuits which cause Lone AFib so I may not be clear yet, but the signs are good! I am beginning to feel much better and I understand from others on this site that the longer you remain in NSR the less fatigue.

I was back working part-time 2 weeks after the procedure and although still in recovery phase the only thing I am avoiding is excessive physical exercise.

Koll I believe said he was back working on his farm almost the day after, albeit not doing anything strenuous.

Maybe your husband would benefit from reconsidering his options and talking it over with his specialist, who I do hope is an EP?

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Thanks for the reply, you seem very like my husband. I think he's wary of the ablation because of the possible after effects and perhaps a 3 month recovery period. As I've said he works away (in Jersey) so it means he has to come home to have the ablation and may be off work for some time, also when he does go back to Jersey he'll be on his own. He has a physical job so not sure if he'd be able to cope, I doubt if part time would be an option with his company. Did you have many epsiodes of AFib? He now has one every few months whereas before it could be years between episodes. We talked it over with the consultant just 2 months ago and he was fine with the choices although he did say, as you have, that it's more successful when done earlier. It's a tough decision for him. I'm so pleased you're doing well and I'll certainly show him this. Many thanks ... and , yes, his consultant is an EP ... and a lovely man too


I can understand that it may be a difficult choice re work, I am able to set my own schedule which obviously does help.

My AFib started about 10years ago but It took me several years to go to a GP as we travelled a lot and sailed and several episodes occurred whilst in the middle of the Atlantic on a small yacht so no options other than put up with it. It took another few years to get a confirmed diagnosis as like your husband they weren't frequent. About -2 years ago they became much more frequent 3-4 month, then maybe free for 6 weeks and then another lot. The gaps between became less and I would get up to 3 a week so last August decided enough was enough and went for the ablation.

Very glad you have a good EP. Take care and best wishes to your husband.


NB. I had the ablation in Nov, having made the decision in Aug.


10-15 years ago, I had intermittent AF and then gradually it became constant and very bad, I couldn't stand sometimes. Put on drugs for a couple of years, they worked but had weird side effects on my mind, bad memory, all sorts. Made my job impossible.

So had an ablation 8 years ago, it was a breeze and a total, 100%, immediate success. 2nd ablation a year ago, again a breeze and no problems at all except the groin wound for a while, but the AF had gone away so they couldn't do any burning. So due for another hopefully.

I was back doing light work within a couple of days of both ablations (I'm a livestock farmer and restricted myself to tractor work). Other than the groin wound which I had to be careful about, especially getting in and out of tractors, and NO lifting, I felt totally normal. In fact I felt 20-30 years younger but that wore off, so suppose it was the drugs. First ablation, don't know what they gave me, but I went round the ward thanking the nurses, how embarrasing!!!

I didn't have to wait for the AF to go away afterwards, it just went straight away.

Best wishes



Sorry to hear that your husband reacts so badly. I take 50m Flecanide twice a day which seems to work for me to keep AF at bay for most of the time ( 4/5 months since cardioversion ) fingers crossed. Hope all goes well. Teresa


I forgot to mention that I had far more probs with the Bisoprolol which is a drug which is a calcium channel blocker which controls the heart rate, not the AFib, the Flecainide stops the AFib. It made me very breathless. It can also slow the heart beat too much. Funnily enough the one benefit I got from it was that it did control my BP which prior to taking it used to drop to 70/30 at which point I couldn't stand up.


If I were your husband, no way I'd take that again! I didn't feel actually ill with Flecainide, but it did give me mild palpations, so EP told to stop immediately. I'd say it's the wrong drug for your husband, surely, so ask to try something else or has he tried them all?

Flecainide gives me palpitations, Propafenone works but makes me depressed, so just about to try another drug this week, see how that one goes. We're all different with these drugs.




The EP I saw recently said I must have a heart scan before taking flecanide as they have to rule out any underlying heart problem. I will have the scan and also I said that reatherthan take Flecanide, as i have a low resting pulse rate,i would prefer to wait until I have more episodes of AF and then go for ablation and the EP said that was fine.


I also felt really ill, dizzy and nauseous the last time I took flecainide (plus metoprolol) as pill in pocket, a couple of weeks ago. It was the second time I'd taken them, the first time being September 2013, when it didn't affect me quite as bad but I felt really tired and light headed all the next day (I'd had AF overnight, about 7 hours) and my BP was very low (I'm also on Irbesartan for BP).

I don't think I'll take them next time, I felt so horrible it was worse than the AF (only lasted 5 hours that time though), and I was shattered the next day. When I next see my EP I will ask about maybe taking a lower dosage. And if the AF continues to get any more frequent I will definitely look at getting an ablation ASAP.

All the best, Gaye


I have been on and off this so many times since 1992. But to be fair I do not seem to get on with many drugs out there ? Maybe when they pop the pacemaker in I will be past that?

Be Well


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