yikes! sounds like some OCD in there as well if he's so obsessed with checking "possible" side effects...
what about you giving him his meds at specific times in the proper doses (like a nurse at the hospital) so a) you know he's taking them and b)he's not mixing where he shouldn't be. Then keep them under lock and key???
(i've hid my husbands ativan in our car so that he can't abuse the medication and i'm the only one with the key and i sleep with my purse in my drawer beside me with a plastic bad wrapped around it so that if "someone" tries to take my purse out of my drawer then i'll wake up - sounds drastic i know but when it comes to bp, sorry, i don't wanna take any chances.)
has he seen a pdoc or even just normal counselling? maybe hearing it from someone else that he trusts might make a difference. i don't know what to tell you except that maybe he needs to be admitted to a hospital (psych) until his meds can be regulated by professionals... again sounds drastic, but a lot of us here have either had to admit our loved ones to psych so they can get regulated or some of the sufferers of bp on here have gone themselves to get regulated.
you will have to be more forceful than you want, trust me - but in the end (hopefully) it'll be worth the pain?
"Twenty years from now you will be more disappointed
by the things you didn't do than by the ones you did do."
-- MARK TWAIN