Since you're posting in a fibro thread, pain from that was/is being controlled by Oxycontin. My understanding is that Oxycontin should only be used for a short interval as it is a narcotic/habit forming drug.
I too have fibro, but my pain is currently under control with 600 mg. of Neuontin three times a day. I started with 300mg 3x a day, but had no relief until I reached 600mg.
I've read your post a couple of times, but I'm not sure I'm answering the question. Are you asking how to wean yourself off the Oxycontin? I haven't got an answer for that except to say that I took it only when my pain was really bad. Honestly, I was afraid of becoming addicted.
Consult your pharmasist for the safest dosage reduction method.