AF Association
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Flecainide - side effects (feedback wanted)

Several folks here have mentioned the side effects they experienced while taking flecainide. Common ones seem to be dizziness or light-headedness, and fatigue. Those are the two primary symptoms I've experienced, though I have a few others as well.

My symptoms began two days after I started on flecainide 100mg 2x/day on May 8, 2015, the day after a successful ablation. Effects were so bad I quit the drug on June 13. Symptoms have continued on a near-daily basis since then.

What's most interesting about these side effects is that from the very beginning they have arisen shortly after I get up in the morning and then dissipate some variable number of hours later. I would like to know what others have experienced. Have your symptoms come on in the morning and then gone away later in the day?

This is important to me because I'm trying to find out why my symptoms continue. Something in the brain is affected by flecainide, and it displays the same pattern of activation as the release of histamine, which also happens upon waking.

I would appreciate any feedback you might have.

Thank you!

Koda

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I take 50 mg twice a day, and the side effects seem mild but I do occasionally get a bit of dizziness. However, not sure if that is the flecenaide or just a normal experience

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I had to stop taking the drug at 300mg twice a day.  Symptoms included severe leg pain, cold hands and feet, difficulty moving my eyes and arms. Went to hospital they stopped the drug.

I would never consider the drug again. It was a scary couple of weeks.

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600mg a day - isnt the maximum dose 400 ??

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Originally I was on 300mg three times a day .

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nitial dose: 100 mg orally every 12 hours.

Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved. Most patients with SUSTAINED VT do not require more than 150 mg every 12 hours (300 mg/day), and the maximum dose recommended is 400 mg/day.

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I just did as was asked by consultant as I chronic AF WITH FAST VENTRICULAR RESPONSE

I stopped using Flecanidr as I had to visit hospital the hospital due the neurologic problems

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Loquitir, thanks for your reply.  Have you had any neurological issues since stopping flecainide?

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The symptoms stopped after I ceased taking Flecanide and went on disopyramide.

The leg pains are due to the AF.

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Wow!, didn't realise it could ranked up more - I think I'd feel light headed with that much!

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That's a heck of a lot, usually 100 - 200mg daily (taken at 12 hour intervals); 300mg is the 'pill in the pocket' rescue dose if in AF!!??

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Very belatedly.......was this the first time you had had an adverse reaction when taking a new drug? Thanks......research-oriented question.

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Chrysalis, if you're addressing me, I have to back up a bit and clarify. My symptoms could not have been caused by flecainide because they have continued long after I stopped that drug. I am about 99% certain I have Lyme disease, and that it was brought out of hiding by the immunosuppressant drug(s) I was given during my second ablation.

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Lyme? Bummer!! And yes, I was addressing you, Koda--ineptly at best. Thanks for the reply.

Trying to 'ferret out' possible 'pharmaceutical sensitives' (lifetime atypical adverse drug reactions), re mutant drug-processing enzymes, and genetic testing for same.

Are you in the States? (or was that someone else on the thread?)

Are you familiar with genetic testing to identify mutant drug-processing enzymes?

Thanks again....

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Koda, I took 2x50 and then 2x100 flecainide for over a year pre and post - ablation. I use 100 as a pip if necessary now. Prior to going onto flecainide they tried me on atenolol, Amiodarone, Soltalol and Tildiem. As such flecainide is the most helpful for my AF. I now take a daily 2.5 bisoprolol.

My AF  is 98% improved since the ablation but I have a major problem with my mobility and wonder if the drugs may be responsible. My feet feel as though they are held in an iron grip. I cannot walk far without needing a rest and 20 mins gardening is enough. Following a rest I can start again. There is no pain but my legs don't work properly. Relim has recorded that she feels as though her feet are wrapped in cling film and she blames flecainide. Is this the same thing?

I am to see an orthopaedic specialist (11 months wait) but have seen an osteopath recently. There is apparently nothing wrong with my knees and hips. So is it neurological?

I'd be interested to know if anyone else recognises my problem.

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Thanks for your reply.  I can't guess at what's causing your continuing problems, but if they weren't happening before flecainide, it's safe to assume the drug had something to do with it.  If I were in your shoes I'd be researching the neurological dynamics of mobility, with a particular interest in how it's affected by the central nervous system, which is what flecainide acts on.

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I have been on flecanaide 150mg twice a day for 3 months.

I noticed double vision and lack of energy. I exercise 6 days a week and noticed I couldn't get my heart rate up over 130bpm. It felt like I was being held back.

I have just finished 3 month blanking period of 3 and have started reducing dosage, 75 mg twice per day for a week and now 75 mg per day. I will discontinue next week.

I now have more strength and noticed today I got my heart rate up to 145bpm during HIIT and have much more endurance.

The drug has definitely helped maintain NSR during my blanking period but I had the side affects.

Glad to be off it soon.

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The skeptic comes along and asks, how do you know flecainide kept you in NSR? The only way to tell is to not take it and see if you fibrillate. But that didn't happen.

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I was put on flecanaide after I went into Afib post ablation several times in one week. Once I took the first dosage I went into NSR within an hour and stayed there except for 2 short episodes in the following 6 weeks

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Ah-HA! Empirical evidence that it works! Good for you. That's one piece of uncertainty you don't have to deal with.

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Koda, I have been taking 2 x 100mg of Flecainide for nearly 2 years and have had no apparent side effects that I have been aware of - except the total absence of AF. 

In the last month I have noticed mild dizziness which my GP thought was a recurrence of a viral inner ear infection.  However, the symptoms are different - not vertigo like inner ear but 'the staggers' and occurring only after getting up - for about an hour.  Fatigue comes and goes but I think is caused by ectopics - perhaps.

I know it is easy to blame the drugs - especially Bisoprolol - for everything but I had decided to mention the dizziness to my EP next month.

Thank you for starting this discussion - I am very interested in others' comments.

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Thanks, Finvola.  My dizziness is also not like vertigo, which I've had for over 40 years.  I'd describe it as feeling like I just drank a half-pint, give or take a few ounces.  I rate staggering a level 9 on a 1-10 scale (6=weaving, 7=wobbling, 8=stumbling, 10=falling down).  I doubt highly your fatigue has to do with ectopics.  The body recovers almost immediately from missed beats.  My guess is that you and I have similar symptomatology.

Do your symptoms show a daily cycle?  I.e., do they start after you get up in the morning and are they done some time later in the day?

I suggest you mention your dizziness to a neurologist.  And please keep me posted.  I'm very interested in what you find out.

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Finvola, I wonder if you'd benefit by looking into POTS - Postural Orthostatic Tachycardia Syndrom. It's like vertigo, but also much different. I also wonder if the -prolol drugs keep the heart rate so low that it can't respond to the demands, of sudden activity, such as getting up quickly.

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Hi Kodaska - my GP did a fairly thorough exam at the time and was certain it was viral labyrinthitis which did recur in decreasing severity for about a year or so. I had wondered about POTS but the dizziness hasn't recurred in the last 14 months. My EP agreed and at his suggestion I tried twice to reduce Flecainide without success - arrhythmias got worse. Bisoprolol (I think) is the cause of many problems but EP felt my low dose was essential as I had been having Flecainide-induced short runs of AFlutter.

Things have been good in the last 14 months and I don't want to rock the boat again but perhaps Bisoprolol does need looking at - Flecainide has kept my AF at bay for over 3 years now.

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I was taking Flecanide daily for a month but had to stop as it made me feel so ill in the evening. It seemed like a severe digestion problem but I wonder now whether it was constant ectopic beats.

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I take bisoprolol and also get the dizziness and balance problems. I have other possible reasons, damaged inner ear, and postural hypotension. 

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Bisoprolol is a beta-blocker that keeps heart rate down.  That's what's causing your issues.  Your heart isn't pumping enough to supply your body and brain with the oxygen it needs, so you end up in a partial faint.  That happened to me while taking metoprolol.  I stopped the drug and I could function again.  Postural hypotension should resolve quickly, especially if your heart isn't artificially held down.

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I agree, I breathe very shallow to the point where I am asked if I am holding my breath as I have my BP taken. However the oxygen level is normally about 97%. Thanks for that, it's given me more questions to ask. 

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haha, and I thought it was just me that held my breath during BP test or ECG.

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That's the thing though, I'm not holding my breath. I always tend to breathe that way and every now and again I gasp deeply. I've even had breathing tests but nothing was found to be wrong. 

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deep concentration. A customer asked me when I planned to breath whilst fixing her computer. I just laughed, at least I did not have my tongue out at the time.

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I take  One 50mg flecainide tablet three times a day ie one every 8 hours.  I experience all of your symptoms but because I also take 25mg atenolol and a blood pressure tablet Felidopine I think it is the combination of all my meds? I am not sure whether it is just the flecainide or the drug combination? I am fed up of feeling dizzy etc though.

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I take 2*50mg of Flec and cannot take ANY dose of beta blocker without me feeling appalling - I have no side effects on the Flec on its own.

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I know what you mean unfortunately my meds are the only things in combination that control the AF. 

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Isn't Flec supposed to be taken with a beta blocker or something similar?  Flec on its own not recommended?  Not sure...

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have heard that but my cardio quite happy with me taking this +losartan for BP .

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"Like" really means "unlike."  It's awful, isn't it?  Please tell me, do your symptoms show a daily cycle? I.e., do they start after you get up in the morning and are they done some time later in the day?  If so, you and I may have a similar problem.

I suggest you look up flecainide on drugs.com and look for interactions with the other meds you're on.  Some other drugs, like diltiazem, increase the amount of serum flecainide, and it can be mutual.

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My symptoms vary from day to day.  I have good days and bad ptdays.  I find if I am very tired then the syptoms are worse.  The Cardiologist says my meds are the right combination for my particular AF which I have had for 13 years. I have regular reviews of my meds.  My pulse is always quite slow at around 45 and sometimes lower.

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Please advise, is flecanide used in the UK? I am only on bisoprolol 10mg and not been offered anything else. Maybe it's because of my other medications of which there are quite a few. Thanks. 

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I take 2*50mg daily - no side effects , but if I up dose to 200 get dizzyspells and feeling woozy been on Flec for 6 years having reduced the doses to the present level.

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dmac how did you manage the reduction from the higher dose?  When I tried to go down to 50/100 then 50/50 I had such severe PVC's and felt so awful that My EP said to go back up again.

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exercise and trial and error

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Do your symptoms show a daily cycle? I.e., do they start after you get up in the morning and are they done some time later in the day?

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Yes , almost always when I am out walking and try to go uphill.

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I was on 100mg twice a day and got bad headaches breathless and not feeling at all well but after lunch for two hours OK. I cut down to 50mg i  the morning and 100mg at night and this suited me alot more and i was also given amitripyline a small dose at night to help the headaches. Everything went well but now I am back in AF and will have to think about how to take an increase dose.

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Hi. I was on amitryptiline for a different issue but checked interaction with flecainide on drugs.com and found that they did have an interaction which could cause af. Just mentioning so that you are aware.

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I could not take Flec it stopped my heart and caused me to have a pacemaker.  I have taken Sotalol for 5 years.  The episodes of Afib came back after 2 years on the drug, suffered 9 hospital stays then had an ablation last May. A cyroablation.  No Afib but when I tried to get off of it the heartbeats went and stayed well over 100.  Have to be on it 

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I take 50mg of Flec twice a day and 20 mg of Nadolol once a day.  First 3 days I was okay but on the fourth day I started getting dizzy at around noon.   I was sitting then and when I got up I passed out and went to the floor.   I was able to get up immediately but felt dizzy and  nauseous for about 2 more hours.  Day 5 - the same dizziness and nausea.   It is 10 days later now and I am not feeling dizzy or nauseous.  The pharmacist did caution me about possibly  feeling dizzy and passing out within the first few days when taking Flec until the body adjusts to it.  The Flec seems to be helping with the AFIb.

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As well as the common ones you mention i also have nystagmus when looking into bright light and especially when looking to the side without moving my head. All of these are worse in the morning but I have another which is only obvious when coming from dark to light at night. I can see multiples of whatever Im looking at in my peripheral vision eg lots of doorframes,window frames,llines round the outside of the t.v. picture frames etc . However it doesnt happen going from light to dark. When I came off flecanide to see if my ablation had worked, all the symptoms disappeared. 

Hope this is helpful.

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I had the same thing while on flecanide, auditory hallucinations....scared the heck out if me. This was after my ablation when they increased it to 300mg from 200mg...after one week of it I decreased it and then stopped altogether after being terribly sick for month taking it post ablation to point of not being able to eat.  I was also taking the calcium channel blocker which I read even increases the serum level of both dugs when combined.  Awful.

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Had some visual disturbance, but stopped when discontinued daily use.

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I take 300 mgs daily and don't feel very well. Flecanaide is the only drug I take. I feel dizzy, pain in eyes and lots of pain in my legs and feet. I scheduled a consultation with a Neurologist to get his opinion. In the meantime, I have filled a prescription for Pradaxa and will start taking Flecanaide as PIP. This was my decision and my EP has gone along with it. I have been told my EP that when I stop taking the daily dosage I will experience lots of palpitations. At this point, as long as I'm protected from stroke I would rather experience symptoms that the horrible side effects of Flecanaide. I will let you know if the symptoms of the medication go away. Gracey 

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Gracey, thanks for sharing.  You might want to look into the relationship between microglia and neuropathy.  Flecainide suppresses microglial cells, the brain's primary immune system.  With the immune cells disabled you can have all sorts of problems.  I hope that isn't the case.  I feel as you do, I'd rather have arrhythmias than this cursed autoimmune disorder.

Please share your experience with the neurologist.

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Kodaska, I see Neurologist on May 5 and will share what hesays. I don't have much faith that I will get the answers but will keep searching. Will go off the Flecanaide and see if there are any improvements. Keep you posted! Gracey 

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I get numerous symptoms associated with my head/consciousness, viz:

A feeling of pressure in my head like you get when you hang upside down or have a ligature around your neck.

A feeling similar to drunkenness: difficulty focusing my mind, thinking, concentrating, handwriting comes out as a scrawl, typing slow and full of errors.

Partial paralysis of my fingers when I got in from a bike ride and couldn't write my name on a registration form at a reception desk.

Arms feeling so heavy and leaden that it takes an extreme level of exertion to lift them to wash my hair in the shower.

Low blood pressure feeling, with the lights dimming.

Feeling nauseous when I watch moving objects on the TV.

Ocular migraines.

Tingling in my tongue similar to a dental anaesthetic wearing off, or touching the terminals of a battery.

They all get worse when I resume training, and abate when I quit, but they were all present long before I started the meds (Flecainide and Diltiazem). I can mitigate the drunk feeling by eating more, but at the expense of gaining weight.

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I hate to say it, but I suggest you look into the symptoms of Lyme disease.

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with flecainide I have a strange fatigue/depression feeling that descends upon me six to eight hours after each dose. I dont know if it is kicking in then or if the level is low in my system. It has also exacerbated anxiety. I feel constantly tense. I feel wired yet tired. Just had ablation and have to be on it for three more weeks. Was on a higher dose pre ablation and it felt to me like I was slowing dying. I have the tongue feeling also. I feel older than my 95 year old mother inlaw. The only upside is that I have lost 25 pounds since I started this drug. I would like to know if anyone else has had this strange feeling

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please comment on this.

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I wonder if you really need to be on flecainide. I was put on it to prevent arrhythmias while my heart was healing. BUT ... when I asked Dr Cardio if arrhythmias could impede the healing or do any other damage, he said no. So the upshot is that flecainide is given to protect the doctor, not the patient. If I had another ablation I would refuse to take the stuff.

What you do, of course, is your decision. I can't offer anything but my opinion.

Best of luck.

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I really wonder if you need flecainide. If you stay in NSR while on the drug, you'll never know. As I wrote a week ago, "I was put on it to prevent arrhythmias while my heart was healing. BUT ... when I asked Dr Cardio if arrhythmias could impede the healing or do any other damage, he said no."

For this reason my view is that it's best to avoid flecainide unless you get arrhythmias. That's the only way to know if it's needed. And if it isn't, you avoid the side effects.

I don't understand why your symptoms would arise 8 hours after each dose. Flec has a long half-life (20 hours or more), so I imagine it could be the compound effect of one dose while the previous one is still fairly strong.

My view - and this advice is worth exactly what you're paying for it - is that you might stop taking the stuff and see what happens. I'd sure be inclined that way.

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my side effects start approximately 8 hours after I take my dose, usually about 2 or 3 pm. I can feel the depression and fatigue come on

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What time do you take the dose?

Do you have many of the other side effects listed here?

drugs.com/sfx/flecainide-si...

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I take it at 5:00 am and 5:00 pm...yes I have many side effects...see my first post 7 days ago.

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I absolutely hated flec and only stuck it for 2 weeks. It made me feel spaced out for about 2 hours every morning and also I felt like things were moving when I would look upwards or sidewards. I also felt quite surreal when I was on that drug. It felt like I was taking poison and I will never ever take it again. I would rather have my rotten arrhythmias

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Interesting post by the way!

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I like to start bar fights, too. :-)

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I had one of the rare side effects - severe nausea , started 50mg x 2 on a Monday and by Thursday I was very ill.This was three months after my fourth cardioversion . My GP after consulting a cardiologist put me on 25mg x 2 a day for over a week then gradually over the next three weeks built it back to 50mg x 2.

As I was going on a long trip and didnt want any nausea while travelling I didnt start taking Flecanide again for three weeks at which time with slowly introducing it to my system it gave no side effects. Thats fifteen months now and still in NSR , compared to Sotalol its a doddle.

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