I didn't know Vistaril potentiated DXM magnificently until I took some 1 month ago. I hadn't done DXM in 5 years until last month.. I just wanted to try it and see if it felt like it used to.
I made two big mistakes. First, I didn't check to see the Vistaril I was taking for anxiety would magnify the effects of the DXM. Second, I drink Delsym cough syrup.. you know.. the extended release shit? I only drank 180mgs worth of dxm. But no fucking lie it felt like I had drank 600!
Long story short, I was tripping ballz for two days straight! I had to keep taking the vistaril.. 100mg a day. That just made it even longer. I was scared as shit the entire time. I was paranoid thinking the cops were going to beat down my door and bust me for shit I had done in my past. That was not a good trip..
I can't even imagine taking diphenhydramine on top of that. I would have been FUCKING GONE for a week!