I frequently pair diphenhydramine with opiates/opioids, (my DOC is heroin, used intranasally, though I do quite enjoy oxycodone, oxymorphone and hydrocodone on occasion), as a potentiator. The "nod" is one of my favorite things about the opiate high, and regardless of my use of opiates, I frequently use diphenhydramine anyway, due to allergies and as a sleep-aid. As the others said, it really just increases the potential for a nod and a "better" nod, HOWEVER, one should most definitely be extremely careful, especially if one has a low opiate tolerance or has not really taken diphenhydramine before, because you don't want to overdose, and with all potentiators, especially when used by someone with a low tolerance to either drug, the risk of overdose is greatly increased when they are used in conjunction. PLEASE, be careful. Don't feel cocky thinking that diphenhydramine isn't a powerful drug, because like I said, it can increase the potential of an overdose when used with opiates/opioids.