Did try taking a low oral dose (5mg) of 3-ho-pce while feeling mild opioid wd from tapering. This was my first time taking a disso in over 10 years and it was also my first time trying 3-ho-pce. Didn't help, if anything it made things worse as I became more aware of all the shitty physical and emotional stuff I was feeling. Maybe a larger dose would have helped, maybe not. Not interested in finding out any time soon. Gonna lock it up for some time in the future when I'm in a better headspace.
3-HO arylcyclohexylamines are weird ones imho and possibly not strong enough at NMDA. It alone, without opioid tolerance or withdrawal, made me feel weird twice and thus abstaining from any more use.
Interesting that IV ketamine is more efficacious than other ROAs, and might confirm my theory that the speed of onset / "rush" is relevant for tolerance reduction. For me there is a "dissociation threshold" phenomenon, when taking lower dosages, they just cause weird feelings and regret of taking them but once the threshold has been hit, all the discomfort goes and stays away for the duration of the agent. With longer lasting ones, tolerance is significantly reduced afterwards yet disso tolerance itself goes up and next time it requires a bit more to cross this threshold - specially if one had a history of disso tolerance.
That said, it's not a magic bullet unfortunately but can work for the worst, last few mg's of an opioid taper.
Very interesting sounds the combination of memantine / long lasting arylcyclohexylamine + ultra low dose naltrexone.
DXM is a weird one and possibly worse in lower doses than higher, but also possibly cardiotoxic in higher doses and readily able to induce panic attacks in me which lasted for like 2 days so I avoid more than like 450mg DXM altogether. Also it's by far the most psychotomimetic dissociative for me (no experiences with PCP though and 3-MeO caused weird stuff too), which might be distracting but generally isn't what one wants. Though this might be abolished during opioid withdrawal with increased cholinergic load, at least the opposite is true - while on morphine, which alone is indirectly anticholinergic. the psychotomimesis is worse than without an opiate.
One might combine DXM + memantine to get more out of a prescription and avoid rushing into D2 induced mania (which doesn't readily happen unless a stim is introduced but of course YMMV).
Ketamine probably is too short lasting, yet can be extended by re-dosing for days.
I found kratom, when used in single doses/days, not to readily reinforce tolerance and withdrawal unlike classical opioids. Possibly because its mu agonism doesn't recruit beta arrestin, whatever this means. So one could alternate between a dissociative and kratom, possibly while using ULN and pregabalin.
Real unsolved problem imho is PAWS. There dissociatives do help but it seems to be an one shot thing, like the ketamine related rapid antidepressant effects, after one became tolerant to them it doesn't work anymore. Which made me relapse into morphine

looking forward to ULN..