Can you take risperidone and oxycodone together?

Yes, you can, and it's a good idea if you have psychotic depression or borderline personality disorder.

It is less than good idea if you are bipolar, because the SSRI may induce mania - but that's not an interaction, it's the nature of SSRIs.

Also, for schizophrenia, SSRIs may be administered with caution (with or without reisperidone).