Why the need to wean of of Flecainide?

I am curious about all the posts I see online, about weaning off of Flecainide, even the Mayo Clinic site, says you should not just stop.

I have been taking Flecainide for Paroxymal Afib, since 2011. I started on it, while in the Hospital, with my first episode. The Cardiologist there, who I continued to see, put me on 50mg Flecainde twice a day, along with 25mg Metoprolol. After some bad reaction to the Metoprolol, he had me split the dose twice. I was ok then up until 2016 when I had several episodes that lasted over eight hours. He then raised the dose to 100mg twice daily. In 2017 I moved to North Carolina. I was having weekly episodes, although they only lasted a few hours. My Cardiologist there, said he thought the cause was the Metoprolol and said I should discontinue taking it. He said to simply stop it. I did wean off it for about a week though, and it was a real roller coaster ride. My heart would suddenly start racing, but eventually it stopped. So did the Afib episodes!
I have not had an episode since then. That was in March 2017. In 2019 I moved to Germany. Since I have been here, I have not had a single episode. Two 24hr monitors, two years apart, also showed not a single ectopic beat! A few months ago, my Cardioligist here in Leipzig, had me reduce my dose to 150mg a day, as he said my heart rhythm was a bit too slow slow. He thought the 200mg dose was too much. This past week he told me that I should stop taking it entirely, and use it as a Pill in the Pocket. He said since I have had no Afib episodes in four years, he thought it unnecessary to take it every day. I asked if I needed to wean off, he said no. He said Flecainide was not like Beta Blockers, which work on your Adrenaline. He said Flecainide has no withdrawal effects. I decided on my own though to wean myself off. I am now on 50mg twice a day, my original dosage with no ill effects. Tomorrow I plan to halve that, and if I still feel ok, I will then stop entirely. I am curious why everyone says you must wean off the stuff though. On European sites about Flecainide, they state it is not necessary, to do so. They simply say that after stopping it, your Afib might return.

I have stopped flecainide cold many times under multiple EPs. None of them ever suggested tapering and I don't know where that advice comes from or what it's based on. It might be based on nothing, the same way avoiding caffeine is based on nothing.

My EP told me to just stop it cold.

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Ken S
I am curious why everyone says you must wean off the stuff though. On European sites about Flecainide, they state it is not necessary, to do so. They simply say that after stopping it, your Afib might return.

From my perspective, a valid reason would be to find a minimum effective dose, if that dose is > 0. As I posted here, at the end of 2021, because of a big increase in episodes for me I started taking 50mg once a day for two months, then dropped it to 25, then 12.5 and then zero. Had an episode in June 2022 shortly after going to 0, went back to 25, then went down to 12.5 and then 0. Had another episode a few days after going to 0, so back to 25. Then before a bivalent booster went to 50, then booster then 25, then 12.5. About a month after the booster, had an episode, been back on 25 daily. Too quick a ramp down after the shot? 11 days ago drove for 14 hours through stressful driving conditions: subfreezing temps, >40 mph winds, ice, drifting snow and low viz. Stopped for the night not having taken my 25 mg and relaxed and went into afib. It was a classic vagal trigger- long duration stress followed by relaxation with the afib occurring during the relaxation. I obviously don't know if there is a relationship between the vaxxes and my afib. The dosing is my own, not directed by an EP (not that I suggest this for others). I've had 4 episodes in about 16 months playing with the daily flec dose vs.15 episodes in 8.5 months prior. The data I've seen in the literature and I'm sure any EP would say my dose levels have no efficacy.

I also figured out during this process that my PIP dose of flec, which has been 300 mg (as I'm over 154 #'s (70 kg)) is too high and 200 mg works better for me. Prior to figuring this out, in recent times, the 300 mg would convert me to flutter (a very stable rhythm), which I'd have to convert back to afib & then NSR. With 200 mg, the flutter does not happen and conversions are much faster and with much less effort on my part.



Edited 1 time(s). Last edit at 01/23/2023 07:44AM by GeorgeN.

George, Mayo wouldn't add a warning for patients for a complex reason like that. I'm curious why the warning exists but I'm not finding that reason anywhere.

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GeorgeN



I also figured out during this process that my PIP dose of flec, which has been 300 mg (as I'm over 154 #'s (70 kg)) is to high and 200 mg works better for me. Prior to figuring this out, in recent times, the 300 mg would convert me to flutter (a very stable rhythm), which I'd have to convert back to afib & then NSR. With 200 mg, the flutter does not happen and conversions are much faster and with much less effort on my part.

I am wondering about this too. I was told if I have an episode to take 200mg. I weigh roughly 67kg or 148 lbs. I worry about taking too much, at one time. In the US I was always monitored when changing doses. However here, I have not had an EKG since before. I worry about the effect of too much Flec at one time.

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Carey
George, Mayo wouldn't add a warning for patients for a complex reason like that. I'm curious why the warning exists but I'm not finding that reason anywhere.

I'm unclear exactly what you are referring to in my post. Are you are referring to 200 vs 300 mg for PIP flec? In original PIP flec/propafenone paper, "The dose of flecainide was 300 mg if the patient weighed 70 kg or more and was 200 mg otherwise."

In my case, I'm reporting what I've observed. I've used branded flec (Tambocor - which I've gotten from Europe since around 2008) as PIP for over 18 years. I've monitored most of my afib episodes continuously with my Polar setup over this time. When I started taking flec in 2004, I weighed around 205 #'s. When I figured out that chronic fitness was a likely contributor to my afib, decided I needed to add detraining to my afib remission plan. As I did this, I started gaining weight. Obviously adding longer duration and more intense exercise was contraindicated, so I changed my diet and keto adapted in 2009. Over time, I dropped my weight to my current 168 #'s. The first time I used flec, it took 20 hours to convert a 2.5 month episode. I had another episode a month after that and it also took 20 hours to convert. I assume this long time to convert may have been due to atrial stunning lingering from the 2.5 month episode. After that conversions were much shorter: 1 to 3 hours for the first 7 or 8 years. More recently, there have been some longer conversions, the longest being 9 ish hours in June 2021. That happened to be the only time I used generic flec. As I continuously monitor my episodes, what I started to see more recently were transitions from afib to high rate tachycardia, which I assumed may be flutter. As I only have a single lead Kardia, I cannot confirm what the rhythm actually is. In the recent past, this has gotten much more common. I found I needed to get this rhythm back to afib for conversion to occur. Subsequent to dropping my PIP dose to 200 mg, this tachy has not occurred. In June 2022, I happened to use some flec that expired in 2014. As I chew the flec before swallowing to get it into my system faster, I could tell by the taste that it had likely oxidized and was likely less potent. Immediately after chewing it, I thought i'd made a stupid mistake. As it turns out, I converted in around 90 minutes with no tachy in the data. Reflecting on this afterward, I hypothesized that this was a less potent dose. So the next episode I used recently purchased flec at a dose of 200 mg. Again, a 2 or so hour conversion, without any tachy in the data. I've done this 2 more times since, all with relatively quick conversions and no tachy in the data. In retrospect, I wonder if my long conversion in June 2021 with generic flec was much longer because the generic flec is somewhat more potent than the branded Tambocor?

This is what I've observed in me, not saying it applies to anyone else. Before cutting my dose, I was seriously considering an ablation as the trends were certainly going in the wrong direction.

So before I contact my Cardiologist, and make him think I am a total worry wart. I wondered if at 148 lbs or 67kg, is 200mg at once, too much. I worry about adverse affects. Also can anyone tell me is 200mg at once roughly the same as 100mg twice a day. As far as how much is in your system at one time.

Besides weight, another consideration with Flecainide is genetics. I got into trouble with this as I am a poor metabolizer of CYP2D6 and Flecainide is metabolized through this pathway. Being a poor metabolizer of this pathway means that I built up a higher level of Flecainide in the blood. I was prescribed 150 mg BID and ended up with complete heart block. Those who have had genetic testing like 23 and Me or Ancestry, may have been given information on the CYP liver pathways that metabolize medications.

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Ken S
I wondered if at 148 lbs or 67kg, is 200mg at once, too much. I worry about adverse affects. Also can anyone tell me is 200mg at once roughly the same as 100mg twice a day. As far as how much is in your system at one time.

200 mg in once dose will give you a higher dose in the bloodstream than 100 mg twice a day due to the half-life.

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Ken S
So before I contact my Cardiologist, and make him think I am a total worry wart. I wondered if at 148 lbs or 67kg, is 200mg at once, too much. I worry about adverse effects. Also can anyone tell me is 200mg at once roughly the same as 100mg twice a day. As far as how much is in your system at one time.

Hi Ken,

At 148 #'s (67 kg), you are within the guidelines for a 200 mg PIP flec dose. Unless you are experiencing issues, I would not worry about it. 100 mg 2x/day would lead to a lower peak serum level than 200 mg at once. The nominal half life of flec is 12 hours, so a peak dose of 100 mg 2x/day would be the same as taking 150 mg at once. Of course the half life can vary from person to person, but you get the idea.



Edited 1 time(s). Last edit at 01/23/2023 05:57PM by GeorgeN.

Thanks!

Thanks! Genetics was never mentioned to me, ever.

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Ken S




I also figured out during this process that my PIP dose of flec, which has been 300 mg (as I'm over 154 #'s (70 kg)) is to high and 200 mg works better for me. Prior to figuring this out, in recent times, the 300 mg would convert me to flutter (a very stable rhythm), which I'd have to convert back to afib & then NSR. With 200 mg, the flutter does not happen and conversions are much faster and with much less effort on my part.

I am wondering about this too. I was told if I have an episode to take 200mg. I weigh roughly 67kg or 148 lbs. I worry about taking too much, at one time. In the US I was always monitored when changing doses. However here, I have not had an EKG since before. I worry about the effect of too much Flec at one time.

My EP told me they use 3mg/kg of body weight for the Flecainide conversion dose in the Hospital. So for a 148lb/67kg person, this would come out to 201mg of Flecainide. (I need to verify if this was by mouth or IV, and if that would change the dosage based on the route of administration). The things is you need to factor in weather you are already pre-loaded with the Flec. If you have already been taking a daily dose of Flec, then your conversion dose needs to be lower, than it would be if your system was clear of any Flec. That is how my Flec adverse reaction/oversdose happened, 300mg on top of the pre-exsisting Flec in my system from a daily dose I was taking.

As far as the concern about overdosing, most of the time you would feel compromised for awhile at a particular dose, and that would be your warning to back off. Things like feeling woosey, decreased ability to move around or feeling faint are common signs of the cardiac decompensation that can occur from Flecainide. Of course, there are those who just going into Torsades De Points (deadly Arrhythmia), but that happens mainly in those with cardiac structural defect or poor pumping ability (ejection fraction). Having lived through a Flec induced NDE, I definately recommend tritrating up slowly on PIP conversion doses, even if it means you might not convert right away.

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GeorgeN

So before I contact my Cardiologist, and make him think I am a total worry wart. I wondered if at 148 lbs or 67kg, is 200mg at once, too much. I worry about adverse effects. Also can anyone tell me is 200mg at once roughly the same as 100mg twice a day. As far as how much is in your system at one time.

Hi Ken,

At 148 #'s (67 kg), you are within the guidelines for a 200 mg PIP flec dose. Unless you are experiencing issues, I would not worry about it. 100 mg 2x/day would lead to a lower peak serum level than 200 mg at once. The nominal half life of flec is 12 hours, so a peak dose of 100 mg 2x/day would be the same as taking 150 mg at once. Of course the half life can vary from person to person, but you get the idea.

Just make sure you didn’t take any flecainide the prior 24 hours before taking the 200mg PIP. 200mg is the maximum for your weight within a 24 hour period.