it is a pain reliever. it has a complex way that it works and it is not considered a narcotic
most common side effects are- tiredness, nausea
wiki says-
The mode of action of tramadol has yet to be fully understood, but it is believed to work through modulation of the GABAergic, noradrenergic and serotonergic systems, in addition to its mild agonism of the μ-opioid receptor. The contribution of non-opioid activity is demonstrated by the analgesic effects of tramadol not being fully antagonised by the μ-opioid receptor antagonist naloxone.
What he is saying is that from what they understand Tramadol works by attaching to the GABA receptors which is the same receptors that valium and xanax work on,alcohol too.This tends to calm a person.
It also attaches partially to the mu receptors which opiates like morphine do.Although it does not cover the receptors fully like a opiate agonist does.
So what happens is your are slightly calmed and there is also a anelgesic effect making this drug have the pain killing strength equal to a tylenol #3...Hope this helps.......Dave