There's no definitive answer, really. It varies from person to person quite significantly. From my general experience, and what I've read on these boards and others, I can tell you that:
-SSRIs aren't usually effective for DP/DR, though for some they can help, especially if the person in question is dealing with depression and/or anxiety as well.
-Antipsychotics are usually ineffective, or even make the condition worse, although I have seen at least one case where an antipsychotic (risperdal) was said to have "cured" someone over 6 months.
-Benzodiazapemes are often regarded as the most effective, especially Klonopin. But even these very often do little to dent the DP feelings significantly.
-There's a bunch of other medication - such as anticonvulsants like Lamictal - which supposedly help some people. But I don't know about these myself, so hopefully someone who does will contribute what they know here.
The bottom line is that there's no set answer to your question. Some medications help some people, others don't. You'll only know if you try them, I guess. Personally I'm getting through this without medication.