Not to mention it will make you SUPER constipated if you're a regular opiate user. I use opiates daily and have tried everything for potentiation. Including 6 loperamide one time, didn't do anything. I was constipated when I took it, and needless to say I was really constipated after. Terrible idea. For me its just cimetidine or grapefruit juice.
Benadryl, Benzos work somewhat, but its just an add on effect. Not really interacting with the opiate, just adding drowsiness. Best outta everything is MJ, I don't smoke enough to get stoned, just a small bit and it seems to bring out some of the euphoria of dope, oxy, morphine or whatever I'm on. (Never tried quinine, heard mixed things about it)