Ultram is an anglesic that acts like a narcotic. It is completely synthetic. I'll let someone with more scientific knowldege give the breakdown. But that is what my doctor told me. Personally, I find Ultram to be more effective than Darvocet and not as effective as Hyrdo. Unlike other forms of opoids, this drug if you take too much feels very chemically induced. You really can't abuse this drug too much, at least I can't. I feel strange when I take too much, even at the 100 mg dose I feel kinda out of it. It really makes me buzzy, not in a good way. Hydro is better for me because it gets rid of my pain without any buzzy effects. Anyway, I hope that answers you quesiton a little bit.