600mg of morphine?! Whoa! At the most, I can handle half of that (orally) and I've been taking painkillers daily for well over a decade.Yeah, this substance class is nasty indeed (the antidepressant venlafaxine is very similar to tramadol, both structure- and mechanism wise, it is just more potent as a SNRI and doesn't metabolize to the real deal, O-DSMT, but against common knowledge it's just the metabolite, besides that venla induces headache when taking too much too fast, I feel almost no difference between these two)
I've stopped counting how many times I tried to get off venlafaxine and never made it through more than 4-5 days of this anhedonic depressive restless fatigued jittery sweaty diarrheaic hell. Morphine is a walk in the park in comparison to quit, not literally but it's much easier and I was at 600mg/d.
Baclofen seems to work for alcohol, unsure about opioids. Only tried it once and low-ish doses did nothing, above a certain threshold it became pretty uncomfortable. Sweating, bad physical feelings, weakness - not what one wants to experience when withdrawing I guess. I'd say the NMDA antagonists/dissociatives are more promising and with phenibut it's the gabapentinoidergic activity which helps not the GABA-B one but YMMV, interested in reports!
Just recently I read that dopamine agonists like pramipexole or ropinirole which are used against RLS and Parkinson's, are able to block opioid withdrawal or a good part of it (in rats, that is, but it makes sense because opioids increase dopamine and dopamine-agonist-withdrawal symptoms read like opioid withdrawal).