My health plan neurologist prescribed Periactin since I was having headaches and insomnia. It is an anti-histamine that is supposed to help the brain settle down. It sure settled my brain down. It settled into a deep depression like I had never experienced before.
I stopped it after only one day.

I had also been put on Indocin (an anti-inflammatory drug) It made me nuts. I could not think straight. I could walk into a room and forget which way I just walked in. I was in Wash DC and went down into a underground Metro Station. I realized that it was for the wrong train but was so lost, I could not figure out which escalator to take back to the surface. They each came out at very distant parts of the area. It scary to have meds mess up your mind so bad.

Since then, I am very careful about "Off Label" uses of drugs.