my husband has cronic pain disorder for 6 yrs now. he is 53 yrs old .hes been on oxycodone and tizanidine during the day. at night before bed he takes gapapetin for 6 weeks. he says hes having side affects mentally and physically. irriatable, over sleeps wakes up in early am 2-3 awke for awhile then back to sleep and over sleeps. said tey gab pills off ste him in many ways. he wants to quit taking the gab pills. how will this affect him , and for how long ? THANK YOU, tAMMY