Flecainide toxicity

I wasn’t reckless and didn’t take his dosage of flecainide. However I did land up 3 days in ICU. Flecainide isn’t a drug one experiments with.

His doctor told him to take 300mg as needed without explaining the limit of 300 in a 24 hour period. Not 300mg “as needed”, another 300 an hour later and another 300 later on.

For those who think flecainide is harmless to repeat PIP dosage, think again:
[www.eplabdigest.com]

Plus to repeat for those who are new: the 300mg dosage is for those who weigh more than 154 pounds. Otherwise the maximum 24 hour dose is 200 if you weigh less.



Edited 5 time(s). Last edit at 10/23/2020 12:53AM by susan.d.

Wow Susan! I hope you are feeling better now!
Ken

It’s been 14 months. Thanks Ken. I didn’t qualify weight wise to take the 300mg dose. My hr remained between 24 to later 37 for three days while in the icu. I had many frequent (as high as 1500ml each time) urine dumps. I had an ablation the following month.

Flecainide has a black box warning with risks. I hope nobody else experiences a flecainide overdose. Thus me posting this link and topic.



Edited 1 time(s). Last edit at 10/20/2020 11:09PM by susan.d.

My understanding based on research is that the max bolus dosage (PIP) is 300mg if your over 154lb, and 200 if your under that. However in clinical practice, the total daily 24hr dosage is 400mg for those with no cardiac structural issues (Lone AF), as some take 200mg X2 daily as a maintenance dose. Perhaps the research has recently changed. If your taking a bolus dose of 300mg to convert, then you need to wait several days for the Flecainide levels in your body to drop back down before taking another bolus dose. I have taken bolus doses every 24 hrs, but my 2nd dose is less than the first one, because there is still residual Flecainide in my system. For example 250mg on the first day, then no subsequent doses until 24hours later, then my bolus dose is 200mg.

The medical literature is confusing on the max daily dose. Notice the last paragraph in the following exerpt states "Maximum dosage is 300 mg/day. Clinical practice guidelines recommend flecainide 50 to 200 mg PO every 12 hours to maintain sinus rhythm in patients with atrial fibrillation without structural heart disease."

From PDR.net [www.pdr.net].

For the pharmacological conversion† of atrial fibrillation or atrial flutter.
Oral dosage
Adults

200 to 300 mg PO as a single dose. Clinical practice guidelines recommend flecainide for pharmacological cardioversion of atrial fibrillation or atrial flutter, if no contraindications exist. Flecainide is also recommended in combination with a beta blocker or nondihydropyridine calcium channel blocker to terminate atrial fibrillation out of the hospital once observed to be safe in a monitored setting. Administer beta blocker or nondihydropyridine calcium channel blocker 30 minutes or more before flecainide. Avoid use in patients with coronary artery disease and/or history of myocardial infarction.

Oral dosage
Adults

Initially, 50 mg PO every 12 hours. Increase dosage by increments of 50 mg PO twice daily every 4 days until a satisfactory response is achieved. Maximum dosage is 300 mg/day. Clinical practice guidelines recommend flecainide 50 to 200 mg PO every 12 hours to maintain sinus rhythm in patients with atrial fibrillation without structural heart disease. Avoid use in patients with coronary artery disease and/or history of myocardial infarction.

My prescription bottle for Flec. says: Take one tablet 2 X a day. They are 100 mg each. I did that before and after my ablation, then two months after the ablation, I was told to stop. Then to use the Flec for pill in the pocket as needed by the Dr.: Two tablets immediately after the start of afib, once a day. Total of 200 mg a day. I weigh 170. Now, only one episode since May which was stopped with the Flec in a couple of hours.

I have experienced zero issue with Flec. It seems to work wonderfully well. Anyone taking 300 mg or more a day and weighs less than 154 lbs - Someone screwed up big time.

Yeah, someone screwed up big time. Me by listening to a new ep my small vessel dr was bugging me to see (to have as an full umbrella attending at the hospital as retainer if I was ever hospitalized) and by not listening to my trusted ep who I do trust with my life.

The theme of the link is lack of communication. That guy was told to take 300 mg as needed so he took 300 300 and a third 300 dose. My ep simply didn’t elaborate to educate me. Had both that guy who took 900mg was correctly informed and I had an explanation (my fault by not bugging him on why?)...things would had been different.



Edited 3 time(s). Last edit at 10/21/2020 11:44PM by susan.d.

Yikes!!!! So glad everything worked out for you.

The most I have ever taken in a 24 hr period was 300mg. I had the flu and was a total wreck. Then I went out of rhythm to add to the nightmare. I was tempted to take more but spoke to the attending that night and he strongly advised against it. Actually considering my state he did not sound too thrilled that I had done the 300 mg.

The problem with flecainide is due to CYP450 inhibitors (liver enzymes levels affected by drugs interactions), if one takes something as benign as a supplement (echinacea, milk thistle, for example) or drugs that may affect the flecainide levels.

“Other medications can affect the removal of flecainide from your body, which may affect how flecainide works. Examples include asunaprevir, cimetidine, fluconazole, certain HIV protease inhibitors (such as ritonavir, tipranavir), anti-seizure drugs (such as phenytoin, phenobarbital), among others”

So you may think your 100mg BID is safe, it may affect your liver enzymes from fully working properly at that prescribed dosage.

Here is a handy link to read:
[heart-disease.emedtv.com]
Or
[www.mayoclinic.org]

Quote
The Anti-Fib
Clinical practice guidelines recommend flecainide 50 to 200 mg PO every 12 hours to maintain sinus rhythm in patients with atrial fibrillation without structural heart disease. Avoid use in patients with coronary artery disease and/or history of myocardial infarction.
.

My understanding was if one develops structural heart disease they need to discontinue flecainide. That was the opinion of my mom’s cardiologist. I think the disclaimer means if you don’t have structural heart disease you are ok to take flecainide at the recommended strength dosage.



Edited 2 time(s). Last edit at 10/21/2020 09:27PM by susan.d.

"The publication of the Cardiac Arrhythmia Suppression Trial (CAST) study in 1989, which was designed to investigate the efficacy of class I antiarrhythmic agents moricizine, encainide or flecainide in patients after myocardial infarction with reduced ejection fraction and frequent ventricular ectopic beats, resulted in a major revision of the role of these antiarrhythmic drugs. Thus, while flecainide suppressed ventricular ectopy in those patients, a threefold increase of arrhythmic death was recorded compared to placebo. Based on CAST results, flecainide nowadays is not recommended for patients with structural heart disease and coronary artery disease. However, it is recommended as one of the first line therapies for pharmacological conversion as well as maintenance of sinus rhythm in patients with atrial fibrillation and/or supraventricular tachycardias without structural heart disease."

[www.ncbi.nlm.nih.gov].

Quote
GeorgeN
"The publication of the Cardiac Arrhythmia Suppression Trial (CAST) study in 1989, which was designed to investigate the efficacy of class I antiarrhythmic agents moricizine, encainide or flecainide in patients after myocardial infarction with reduced ejection fraction and frequent ventricular ectopic beats, resulted in a major revision of the role of these antiarrhythmic drugs. Thus, while flecainide suppressed ventricular ectopy in those patients, a threefold increase of arrhythmic death was recorded compared to placebo. Based on CAST results, flecainide nowadays is not recommended for patients with structural heart disease and coronary artery disease. However, it is recommended as one of the first line therapies for pharmacological conversion as well as maintenance of sinus rhythm in patients with atrial fibrillation and/or supraventricular tachycardias without structural heart disease."

[www.ncbi.nlm.nih.gov].

Based on discussion and linked study I should probably not be on flec due to structural heart disease concerns. Will certainly bring the research article to my upcoming cardio appt. So thanks for that. Flec has been somewhat successful for me. What are some of the best alternatives?

Multaq is another some people use. It may have less side effects but it isn’t as effective, some say, as flec.

Here are others:
[www.healthline.com]



Edited 1 time(s). Last edit at 10/21/2020 11:36PM by susan.d.

Quote
walt
Based on discussion and linked study I should probably not be on flec due to structural heart disease concerns.

Have you had a prior heart attack or have you been diagnosed with heart failure? If so, then yeah, you need to bring it up with your doc sooner rather than later. Otherwise, it can wait and probably isn't a problem.

Quote
Carey

Based on discussion and linked study I should probably not be on flec due to structural heart disease concerns.

Have you had a prior heart attack or have you been diagnosed with heart failure? If so, then yeah, you need to bring it up with your doc sooner rather than later. Otherwise, it can wait and probably isn't a problem.

It is the “structural heart disease” reference which I qualify under that is a concern to me.

Quote
walt
It is the “structural heart disease” reference which I qualify under that is a concern to me.

I understand, but what is this structural heart disease you speak of?

You'll hear both sides, based on my CAC score alone cardiologist would not prescribe flec but would prescribe a statin. LOL With < 5% stenosis, no heart attack history, passing stress and echo, (cardi knew all this too) my EP local and Dr. N had no issue with prescribing flec. I just wish it worked as well as many of you have success with.

Quote
Carey

It is the “structural heart disease” reference which I qualify under that is a concern to me.

I understand, but what is this structural heart disease you speak of?

Valvular Heart Disease (Aortic) and Mitral Valve Regurgitation

This is a serious subject with serious consequences. AFAIK many of the deaths seen in CAST were also due to lack of a beta or calcium channel blocker. I could be wrong about that as I am going from memory and my layman understanding of the paper. The deaths weren't immediate if I recall correctly - so just because you took it once or for weeks safely doesn't guarantee future results. Nonetheless, I would definitely get with your MD before taking more flec.

I have been taking Flecainide for 12 years daily. Is there a long term side effect? Is there a newer drug that one should consider.
From to time, I wonder if I still really need it or if I should cut dose in half.
Thanks to forum contributors and wishing all dealing with afib well.
Tibbar

Quote
tibbar
From to time, I wonder if I still really need it or if I should cut dose in half.

If you are willing to accept an episode risk, titrating down to find your minimum effective dose could be an option. In my opinion, using only what you need is appropriate. Discuss with your doc. You wouldn't need to start in half steps. For titrating down a steroid med for a cat that needed to be reduced slowly, I used a single edge razor blade to cut the pill into various fractions.

Thanks George...

Had appt with my EP and showed him the previously linked article. He was extremely familiar with the study and spoke about it easily. Anyway, he talked about the control group and terminology used in the study which he felt has led to confusion in interpreting or generalizing results. He feels very confident that, in my case, flecainide is still a viable option for me. I feel comfortable with his decision.

Excellent to hear Walt!

And I'm very glad you conferred with your EP, which is our constant recommendation when making such medication/procedural decisions for your own health.

It's always important to remember ... and continually emphasize ... that while a lot of interesting and often insightful information is shared from our large patient group at Afibbers.org, none of these comments and anecdotal personal experiences shared on our forums are substitutes for your own EP or cardiologist working with you to make informed medical decisions on your behalf.

Both Carey and I are well-informed about much of the EP/Cardio world, but it also goes without saying that neither of us are board-certified physicians, and we thus do not prescribe any direct medical advice.

Afibbers.org is blessed too, to have so many very generous long term and seasoned contributors sharing nuggets of anecdotal insights from their own varied medical 'experiences of one'. And thus, a good rule of thumb is to just use any of our collective comments on these forums as further 'food for thought only', that you might bring up with your physicians, hopefully to add more depth and richness to your decision making process with your own Doc.

Okay that's it for my obvious periodic disclaimer! :-). We have a constant stream of new posters and many more new lurkers that I'm always thinking of as well for such reminders.

Cheers!
Shannon