Did some research in peer-reviewed journals (IOW legit shit). Here are my findings:
Try grapefruit juice with your oxy - whether it be Percocet, Roxi, OxyContin - for the same reason you should take it with your vitamins and never with blood pressure or cholesterol meds: it increases absorption and therefore potency.
Oxycodone has three main metabolites, the first two of which are not particularly notable: noroxycodone, noroxymorphone, and oxymorphone. Oxymorphone is four times more potent than oxycodone and can cross the blood-brain barrier like few other opioids can. It’s so good that it comes as a prescribed drug of its own, which you may know as Opana or Numorphan.
Compounds in grapefruit juice called furanocouramins increase the blood concentration of both oxycodone and oxymorphone, and in half the time than without grapefruit juice. Yay!
Because of the higher potency, please avoid booze unless you have a (good) track record of concomitant opioid and alcohol use.
If you’ve never experienced oxymorphone, you can read up in the Erowid Vault.
And remember: Respect the drugs, or they’ll turn on you.