How Long After Stopping Does Flecainide Stay in System?

[missyf323]

Was on for 6 weeks post cryo and last pill was last evening. Wondering how long it will be in my system. Thank you.

[Hidden]

Its half life is 12 to 27 hours so it probably is out of your system in 24 to 54 hours? But its effects can last longer. Here is info I copied and pasted, probably way tmi😉

Metabolism and drug interactionsEdit

Flecainide has high bioavailability after an oral dose,[25] meaning that most of the drug that is ingested will enter the systemic blood stream. Peak serum concentrations can be seen 1 to 6 hours after ingestion of an oral dose. While the plasma half-life is about 20 hours, it is quite variable, and can range from 12 to 27 hours.[26] During oral loading with flecainide, a steady state equilibrium is typically achieved in 3 to 5 days.

The majority of flecainide is eliminated by the kidneys, with the remainder metabolized by the cytochrome P450 2D6 isoenzyme in the liver.[27] Therefore, alterations in renal function or urine pH will greatly affect the elimination of flecainide, as more is eliminated by the kidney than by the hepatic route.

Because of the dual elimination routes of flecainide and its tendency to decrease myocardial contractility,[9] flecainide interacts with numerous pharmaceuticals and can potentiate the effects of other myocardial depressants and AV node blocking agents. In addition, flecainide can decrease the metabolism or elimination of many (but not all) agents that use the cytochrome P450 enzyme system.

A full list of drug interactions with flecainide can be obtained from the manufacturer. Some important drug interactions with flecainide include:[citation needed]

Alcohol – may further depress normal heart function

Amiodarone – inhibits cytochrome P450 2D6 and may increase flecainide levels

Cimetidine – increases flecainide levels by 30% and half-life by 10%

Digoxin – may increase digoxin levels

Paroxetine – increased effect of both drugs

Propafenone – increased effect of both drugs and increased risk of toxicity

Quinidine – inhibits cytochrome P450 2D6 and may increase flecainide levels

[missyf323 in reply to Hidden]

Thank you Hoski. Lots of info but appreciated. Happy Holidays. Missy

[secondtry in reply to Hidden]

Thanks Hoski much appreciated!

[ILowe]

To follow up on Hoski. There are some rules of thumb about the half life, I have read somewhere. Three half-lives time is usually considered safe to start another drug (12.5%), and five half-lives (3%) it is as good as out of the system unless there is some other good reason. But you have to be careful reading the pharmacy information, since there are sometimes more than one half-life involved. A drug can be metabolised into two or more other chemicals which have drug-effect, and each of these has a half-life.

[missyf323 in reply to ILowe]

Wow- thank you so much for explaining so clearly. Really after a ballpark estimate to monitor any changes but having an understanding is even better; thanks again.

[jennydog]

Brilliant replies from Hoski and ILowe.

Last Thursday I started a new tablet, Duloxetine, for a neurological condition. Its leaflet stated 1 in 10 would suffer nausea which would be temporary. 4 hrs after taking the first tablet I felt sick and this continued for over 5 miserable days. So now I'm back on to a very low dose of Gabapentin which has a very calming effect on my heart.

I consider flecainide to be my best friend but it obviously doesn't suit everyone.

[jedimasterlincoln]

When I flipped into AF/flutter on Wednesday AM I took flecanide before readmission at 9:55am.... and I had been given IV flecanide earlier in the night, the NSR supposedly kicked in but high HR (rising to 190 on exertion) persisted.

I omitted evening flecanide and the HR dropped (or flutter resolved) at 10pm, some 12 hours after my last dose orally.

[missyf323 in reply to jedimasterlincoln]

Thank you for sharing your story--hoping you are feeling ok now. Happy Holidays.