It didn't do much for me when that was all I was given besides the phenobarbital taper to get off benzos in one of my psych hospital stays. It is pretty benign, though, from my understanding. It is an anti-histamine, rather like any other sedating anti-histamine OTC or rx only. I was unaware that it actually inhibited a liver enzyme for true potentiation of opiates, but I guess that is a plus. Taken by itself it is not recreational. I don't know much about high dose hydroxyzine, or if it induces delirium as diphenhydramine does, but I assume it would. Don't know if that is particularly safe, though. Not the best idea with diphenhydramine, that is for sure.