Some info for all the insomniacs out there. Periactin is an antihistamine used mainly for allergies etc, but have found it does a few other things. Does help you sleep like most antihistamines(personal experience) but is not suppose to interfere with your sleep quality like benzos which supress stage 4 deep sleep, and is used to help people withdraw from benzos. Also used for migraines & nausea. Also read that it has some calcium channel blocking effect which is how lyrica etc is suppose to work. And if your on ssri's it can help block serotonin at specific sites to negate the sexual side effects of ssri's with out interrupting the antidepressant effects. Apparently these effects occur before the sedation kick in, so when all is done roll over and go to sleep, lol. They usually come in 4mg tablets which i usually take 1-2 =8mg, Recently they havent helped as much for sleep but researching have found that 8mg is quite a low dose(but good to start off with),doses can go as high as 32mg a day, so Im going to try a little higher and see how i go. Side effects are increase in appetitte, dry mouth, hang over effect ect which are all dose related. I think this is a medication to use irregularly to avoid any sides, which is how I will use it. And the big plus is its dirt cheap and no prescription required.But talk to your Dr first or have a good google of it. Good luck!