Single doses of immediate release oxycodone start at 5 to 15 mg every 4 to 6 hours and are increased according to need and doctor discretion as opioid tolerance builds. So safe dosing for opioid naive people is between 5 to 15 mg of immediate release oxycodone at once.gain, the answer to this question will depend upon how opioid tolerant your body is and how much/what type of opioids you are currently taking. There are, however, a few guidelines doctors follow when dosing oxycodone.