Related Article: Oral Opioid Medications.
Related Article: How to Write Patient Controlled Analgesia (PCA) Orders.
Related Article: Opioid Conversion, Expanded Table.
Opioid Conversions and Opioid Equivalents
Morphine is used as the reference standard.
| Opioid Agonist | Parenteral Dose (IV, SC, IM) |
Oral Dose | PO:IV | Duration of Action, in hrs |
| Morphine | 10 mg | 30 mg | 3:1 | 3-4 |
| Morphine, long-acting | – | 30 mg | – | 12 |
| HYDROmorphone | 1.5 mg | 7.5 mg | 5:1 | 2-3 |
| OXYcodone | – | 15-20 mg | – | 3-5 |
| OXYcodone, long-acting | – | 20 mg | – | 12 |
| HYDROcodone | – | 30-45 mg | – | 3-5 |
| OXYmorphone | 1 mg | 10 mg | 10:1 | 3-6 |
| OXYmorphone, long-acting | – | 10 mg | – | 12 |
| Codeine | – | 180-200 mg | – | 4 |
| Fentanyl | 0.1 mg (100 mcg) | – | – | 2 |
| Methadone | – | – | – | – |
Tips
- Parenteral morphine is 3 times as potent as oral morphine.
It’s best to consult pain management for Methadone dosing.
When switching from one opioid to another, “dosing must be titrated to individual response. There is often incomplete cross-tolerance among these drugs. It is, therefore, recommended to begin with a 50% lower dose than the equianalgesic dose when changing drugs and then titrate to a safe/effective response”
Use cautious dosing for elderly or debilitated patients, and patients with renal or hepatic impairment.
Immediate-release opioids are recommended for breakthrough pain.
References
Mark A. Schumacher, Ph.D., MD, et al. Opioid Analgesics and Antagonists. Chapter 31. Bertram G. Katzung BG: Basic & Clinical Pharmacology, 9e.
palliative.stanford.edu/opioid-conversion/equivalency-table
palliative.stanford.edu/opioid-conversion/equianalgesic-doses
https://emedicine.medscape.com/article/2138678-overview
Click to access Opioid-Comparison-Chart-Prescriber-Letter-2012.pdf