Baclofen, contrary to common bluelight belief (besides this thread - kudos on knowing what youre talking about baclofen recommenders) is likely going to b e your best option for a switch and taper, as it is a gaba b agonist like phenibut. 3 people I know of who went non-idiot doctors switched them to baclofen and tapered. Ive done it myself and its easy to taper off baclofen painlessly. You don't even have to go that slow. I would leave the gabapentin out of it (which I also have a ton of experience with and a giant bottle full of in my go bag for opiate wd).
Gabapentin is a pain in the ass to come off.
***to those recommending just staying with the "but". I went through exactly what this guy is as I was on suboxone when I did my phenibut phase. I think it is a reaction specific to suboxone that causes it to turn on you so quickly and horribly...this is not your typical tolerance issue of a gabaergic. I was stable on my phenibut dose then one day, completely suddenly it started giving ADVERSE effects of absolute sickness - not lessened effects. It was like all the positives reversed into their opposites (exiteotoxicity, muscle tension, etc) in a day.
I did not have the same problems with baclofen, althoufh I tapered off it quick as I could.
I think its something about the stimulating effects of bupe that made the phenibut turn on me... and yes of fucking course caffeine and nicotine is going exacerbate the shit out of it.
Good luck.
Dont bother with the gabapentin unless t ou just want it as a backup. I would not start taking it unless you absolutely have to. Its a shit drug like phenibut (with regular usage at least)