Hydromorphone to Oxycodone: how to convert safely

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Worked example

1. Total the 24-hour hydromorphone dose — say 8 mg/day oral.
2. Convert to morphine equivalents: 8 mg × 4 = 32 mg MME/day.
3. Convert to oxycodone: 32 ÷ 1.5 = 21.3 mg/day.
4. Apply a 25–50% cross-tolerance reduction: start near 16 mg/day or lower, divided by the dosing interval, with breakthrough doses available.

Try it with your patient's numbers

Cautions specific to this switch

• Hydromorphone is roughly 4–5× more potent than oral morphine mg-for-mg — dose-entry and unit errors with this drug are a recurring cause of serious opioid overdoses in hospitals.
• Preferred over morphine in renal impairment (no clinically significant active metabolite accumulation at usual doses), but still start low in dialysis patients.
• Oxycodone is metabolized by CYP3A4 and CYP2D6 — strong CYP3A4 inhibitors (azoles, clarithromycin, some antivirals) can raise levels substantially.
• No parenteral form is available in the US; if the patient will lose enteral access, plan the rotation to an IV-capable agent before it happens.
• Equianalgesic tables are population averages. Re-assess pain, sedation (e.g. POSS), and respiratory status within hours of the first converted dose, not days.

Frequently asked questions

How much oxycodone equals 8 mg of oral hydromorphone per day?

8 mg/day of oral hydromorphone is approximately 21.3 mg/day of oral oxycodone (8 mg × 4 MME factor ÷ 1.5 = 21.3 mg), before any cross-tolerance reduction. Most patients switching opioids should start 25–50% below the calculated equianalgesic dose.

What is the conversion factor from hydromorphone to oxycodone?

Oral hydromorphone has a morphine milligram equivalent (MME) factor of 4 and oral oxycodone a factor of 1.5, so 1 mg of hydromorphone ≈ 2.7 mg of oxycodone. Equianalgesic tables are population averages — individual response varies, so titrate to effect.

Why reduce the dose for incomplete cross-tolerance?

Tolerance to one opioid does not fully transfer to another. When rotating from hydromorphone to oxycodone, standard practice is to reduce the calculated equianalgesic dose by 25–50% and provide breakthrough doses while re-titrating. Frail or elderly patients warrant the larger reduction.

Is this conversion exact?

No. Published equianalgesic factors are averages with wide interpatient variability, and they differ slightly between references. Treat the calculated dose as a starting estimate, apply a cross-tolerance reduction, and reassess pain and sedation frequently after the switch.