I don't know if there really is any reasoning or 'excuse' as to why you'd rather the trams than other, stronger opiates...but I get it. I'll tell you this...my fiance (who I am going through the journey of recovery with) ALWAYS had opiates on hand when I was on the trams (he has severe DDD and 3 herniated disks) - we're talking avinza <sp?> (time release morphine), vicodin, oxys, percs.....never even thought about them when I had my tram stash. And when I ran out or decided I wanted off the trams...addict mind worked similar to yours...I thought I could wean w/percs (my g-d, who was I kidding!)
I'll tell you the truth though...it was never enough. When I resorted to percs I'd get the opiate high, but more just sleepy and grumpy....and still restless! I wanted my trams. I'm convinced they get you w/the SNRI. Mind you I was taking way above the recommended dosage, but it's like a weak opiate + prozac...music to an addicts ears....UNTIL it turns on you. Makes you someone you'd never want to be, never dreamed you be...took me down...and you can get it on the damn internet. This rx should be scheduled....perhaps it is not appropriate for severe pain, which is why it is scoffed at by many chronic pain sufferers....but it's an addict loophole, and I've seen it destroy so many lives....it's sad.
PS.....nausea....try GINGER! Ginger anything NOT flavored w/corn syrup or sugar (which imo induces that bad feeling.) Ginger tea...sometimes called like 'tummy tamer' - just make sure the % of ginger is high...ginger lozenges (again, sugar free) --- or you can literally just chew on little raw pieces (you can boil first to make the flavor a bit less intense - but not too long or you lose the beneficial part.) I know it's a drag to get up and go out to the store - but this has been really helpful to me so many times and my stomach is totally wussy so I deal w/this often!