Phenergan is very sedative IMO. I think it works for soo long, that when I used 25-50mg to sleep I slept longer than intended every time. Vallergan is similar with shorter duration, very good if you like a high antihistamine dose for sleep or a couple of mg's potentiating opioids . I have used a 1/6 of a phenergan mixed in my 4mg bupe shots, gave a little more kick, but I only did it in the evening and if I was going to sleep. I do not recomend shooting pills!
I must say, now I only use atarax out of the antihistamines. It works for me, I usually take 1-2 with a lower dose of any benzo. They work especially well with clonazpam, since its perhaps the least sedative benzo, and my night time friends zopiclone and zolpidem. It also potentiates my methadone slightly, and helps the itch. I never get nauseus from any opiate, but I hear they help with that too.
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