Hydromorphone to Oxycodone: how to convert safely
Bottom line
1 mg oral hydromorphone ≈ 2.7 mg oral oxycodone (MME factors 4 → 1.5). After converting, reduce the calculated dose by 25–50% for incomplete cross-tolerance and re-titrate to effect.
Worked example
- Total the 24-hour hydromorphone dose — say 8 mg/day oral.
- Convert to morphine equivalents: 8 mg × 4 = 32 mg MME/day.
- Convert to oxycodone: 32 ÷ 1.5 = 21.3 mg/day.
- 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
01 · From
Current regimen
Normalized: 32.0 MME/day
24-hour MME bridge32.0MME/day→↓
02 · To
Target regimen
Incomplete cross-tolerance reduction
03 · Estimated starting pointNo reduction applied
Oxycodone 21.3 mg PO/day
8.0 mg/dayHydromorphone (PO)× 432.0 MMEnormalized÷ 1.521.3 mg/dayequianalgesic− 0%21.3 mg/daystarting estimate
Show calculation detail
1) Start: Hydromorphone 8.0 mg PO/day
2) Convert to morphine equivalent: 8.0 mg × 4 → 32.0 mg MED/day
3) Convert to Oxycodone (PO): 32.0 ÷ 1.5 → 21.3 mg/day
4) Cross-tolerance: 0%
→ Final conversion= 21.3 mg/day
!
Starting estimate, not a prescription. Round conservatively and reassess pain, sedation, organ function, interactions, and clinical trajectory before ordering.
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.
Created and maintained by Yasmine Abbey, MD, MSc · Last reviewed:
Educational decision-support for clinicians. Not medical advice — verify all outputs against your clinical judgment, institutional protocols, and current guidelines.