Sorry,... wont happen agian, i find that the anti-histamine at least for me is determined by wich opiate/opioid i am using due to CYP interaction with drug metabolism, in the instance of certian opioids beind converted to more potent ones, although i take other meds that are very testy with diphenhydramine(SSRI interaction) and chlorpheneramine(SSRI/weak NRI interaction) so these days i have found nothing beats cyclizine , or promethazine wich requires RX and still this one interacts with CYP enzymes, so default to cyclizine, wich seems to have nice potential in itself, as far as providing potentiation without adultering the opiate expirience to much.