Can a patient weaned himself off of oxycontin in four days?

Yes: Be brave. I've known people who have done similar things. You'd do well to talk with your physician first; only he/she knows you, your physiology, & your strengths & weaknesses.

Talk to doctor: Weaning off opioid medications like Oxycontin need to be scheduled by a physician, as if done incorrectly can lead to withdrawal symptoms. Discuss this topic with your prescribing physician.