That's interesting. I know they "caution" against antipsychotics and narcotics, as well as the tricyclics and narcotics, and hydroxyzine and narcotics, but I've never heard of interactions between SSRIs and oxycontin. I've taken both at the same time with no problem. Do you have some kind of enzyme deficiency?
Just curious. You don't have to answer if you don't want to.

Celexa is probably one of the most or the most "benign" SSRIs. It tends to cause very few side effects for most people.

Beta blockers are used a lot for hand tremors not due to any serious cause and are usually very effective.

I would stay away from the SNRIs as they're more likely to cause nervousness, agitation and hand tremors.

Good luck. I hope you get things figured out.