Hey Deathindustrial, I'm sorry you are dealing with the heart bullshit (and the doctors not listening bullshit). I'll be forthright and tell you that like many real life medical issues, yours isn't clear cut and is confusing; I'll probably not clear up much, but I've read a few articles from when I saw this on Friday, and I may be able to share some of the confusion.
Starting with the physiology of PVCs, they seem (according to wiki, citing a cardiac physiology book) to often be caused by excessive cyclic AMP (cAMP) signalling leading to excessive calcium release. This is often caused by drugs which act on norepinephrine receptors to produce cAMP, or drugs which inhibit it's breakdown such as caffiene. Lists of drugs causing PVCs include many different drugs working along these pathways, and don't primarily cite drugs that fuck with ion channels.
Now gabapentin fucks with ion channels, but in a weird way. It interacts with calcium channels, but unlike the many calcium channel blockers, which block the channel pore that transmits calcium into the cell (often of a specific channel class like L-type, N-type, P/Q-type, or R-type).
Gabapentin on the other hand binds to α2δ subunits, which are found in all of these channels. It also doesn't block the channels, instead it messes up their trafficking, causing them to both not get inserted into the cell membrane (instead residing in processing organelles) or to mislocalize. Cells cluster proteins together to respond to a given stimulus (like calcium influx from a calcium channel). Their response often depends in downstream effector proteins nearby, and if any proteins involved are not near one another, the cells won't function properly.
Because gabapentin hits so many different channel types, which are expressed over a wide range of tissue (and cell) types, it is hard to narrow down if there is a specific interaction in the heart (or elsewhere) that contributes to PVCs.
At the end of the day, I think it is always good to do the experiment, and see if something is causing you trouble by taking some time off from it. Knowing if it correlates with gabapentin use is going to be a lot more valuable than knowing a few things about the physiology of it all.
Very interesting to know!
I found this post on reddit the other day. The OP speaks Spanish, so they might not be articulating themselves the best way in English, but they too were having palpitations form gabapentin & mentioned this -
"I have a very bad palpitations using gabapentin and pregabalin, in the accute effects (during the positive effects). Gabapentin has less effect in my heart than pregabalin. Phenibut and baclofen has no effect. I research alot about this and... Pregabalin is known to cause heart failure in some patients. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655846/ And there are a lot of report of heart side effects, including health alert: http://english.prescrire.org/en/5150B1C7E49B41EE113DCC4756EAE06D/Download.aspx Alpha-2-delta (gabapentin receptor) is located in heart and brain in high quantities: https://www.ncbi.nlm.nih.gov/pubmed/11306709 It is known that alpha-2-delta disruption cause arrythmias. And it is known that this receptor disfunction cause heart problems in humans. Disfunction is upregulation or downregulation, excesive agonism, and excesive antagonist. https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=DetailsSearch&Term=93589 And, in erowid, there are reports of pregabalin heart arrythmia with hospital visit and diagnos Do you also suffer from this? Any way to antagonize alpha2delta in the periphery? Taurine doesnt work, I will try with isoleucine. I like gabapentin/pregabalin effects!"
That person is trying to find an antagonist to stop the binding from alpha2delta, so that they can still take gabapentin without the palpitations. But some one in the comments explains to them that even if they did, using an antagonist would just block the gabapentins effects anyway, which makes sense.
I don't know if what all they're saying is accurate, but they did provide some sources. It sounds plausible though I guess. And they seem to be dealing with a similar problem, along with people in the comments. I found many other posts about palpitations on gabapentin too, but none of them went into a detailed explanation like this one did.
So either it's all one big coincidence or there's possibly something to it.
Gonna stick with the experiment for now. Today is day 4-5 of no gabapentin (last dose I took was 900mg on Thursday evening).
I had no PVCs at all yesterday.
Today I seem to be okay, but I do feel a bit of chest tightness & discomfort like I normally get when I'm having PVCs. Like it almost feels like I'm about to have a PVC every few hours, but then don't actually get one. I think I've felt some really mild ones though.
It's interesting you mentioned norepinephrine.
I got into a bad habit through 2021-2023 of taking ephedrine along side my gabapentin & subs, because all 3 seemed to hit me better than just taking my subs alone.
And the night before these PVCs really got set off back in February, I stupidly popped 50mg of ephedrine. I was feeling pretty bummed that night due to never having access to full agonist opioids. Haven't touched ephedrine since though.
So it could also be possible that something else I took gave me the arrhythmia but the gabapentin just makes it worse. Hard to know for sure quite yet though.
During the weeks that I didn't have any PVCs at all, I did drink a couple of iced coffees & seemed fine with those. So I'm reluctant to just blame caffeine. I never take my caffeine dose higher than 100-150mg in a day. And I've been drinking caffeine since I was 12, so for almost 3 decades.
The ER doc explained to me that you have 2 chambers in your heart that normally send electrical signals back n forth to tell each other to beat & keep your heart in rhythm. But with PVCs, the Purkinje fibers (bottom part of the heart) is sending out a signal to one of the chambers, telling it to beat before it's suppose to. So even though it feels like my heart's skipping beats, it's actually an extra heart beat. But there's not enough blood in the chamber when it gets the signal, so it has to pump harder to sort of reset itself. And I feel this sensation as a "flip flopping" or squeezing at the top of my stomach.
He said they're harmless & that it should go away & blah blah. But it still wasn't very reassuring, especially since it hasn't gone away.
It's really difficult to live like this though. Especially when it happens 30+ times in a day. Constant anxiety about wtf is wrong with me & worrying about sudden cardiac arrest or sudden death.
So my guess is that something is causing there to be too much electricity in my heart or is causing the normal electricity that's in there to get re-routed or misdirected.
I was also told that it's a good thing that I'm able to feel them, because a weak or diseased heart wouldn't be able to pump that hard to cause the sensation.
Still not very reassuring though. lol
I'm also kind of mad at myself, cause I did have those 3 weeks recently where I stopped my gaba & didn't have any PVCs for those 3 weeks. I even thought it was gone by that point & was starting to rememeber how it feels to live PVC-free & without all the anxiety & fear that was accompanying them.
But I knew I had to test it out & take my gabapentin again & now it's back. So it's just very suspicious timing. I wish I hadn't of taken it at all now.
My normal daily drugs are just buprenorphine, (use to be gabapentin too) & weed. And I take klonopin when I really need it. And I usually have a coke or something with a little caffeine when I get up in the morning. I never use meth or any other drugs either, at least not within the last 6-8 months.
I guess all I can do is continue to see if it gets better without gabapentin in the picture.
I think I'll quit gabapentin altogether either way though, after reading about the effects it causes on the heart. Not worth the risk.
I appreciate everyone's responses! I will keep this updated! I may even use this post as some sort of outlet to mentally deal with this shit. PVCs fucking suck & this is my first time ever in my 36 years on this planet dealing with something like this. I honestly hope it's just the gabapentin, cause there's no way I could live with dealing with these things all the time. It puts my anxiety into overdrive & can totally ruin my day.