My Husband Has Chronic Pain From Injuries From Vietnam ,he

My husband has chronic pain from injuries from Vietnam ,he has been taking hydrocodone for about 2 years he say it makes him feel more pain and his hand shake for a while after he takes it he has been taking his old tramadol every other dose he said he doesn't feel any pain after taking the tramadol and doesn't shake is this going to affect him taking 2 different pain killers as he says he's gonna get off the hydrocodone the side effects really make him sick . And how should he come off the hydrocodone is the way he's doing it ok
The emergency room doctor told him that his body would look at the tramadol as anew drug since he had been off of it for 2 years.