Opioid conversion ratios used in palliative care: is there an Australian consensus?

Intern Med J. 2014 May;44(5):483-9. doi: 10.1111/imj.12401.

Abstract

Background: Opioid switching or rotation is reported to be a common practice in palliative care. Published tables of opioid conversion ratios have been found to vary in their recommendations, potentially leading to significant differences in clinical practice.

Aims: To identify common practices in the calculation of opioid equianalgesia by specialist palliative medicine practitioners and trainees.

Method: An anonymous, cross-sectional, online survey completed by 85 Australian palliative care specialists or advanced trainees. Questions focused on conversion ratios used in switching between oral and parenteral opioid doses; conversion ratios used when switching from other opioids to oral morphine; and practice of commencing methadone.

Results: The majority of respondents calculated equianalgesic doses for morphine, oxycodone and hydromorphone using the same conversion ratios. Methadone was used almost equally as either the sole opioid or as a 'co-opioid'. The majority surveyed converted slow-release hydromorphone differently to the manufacturer's recommendations.

Conclusion: Further discussion among Australian palliative care specialist organisations is recommended in order to produce uniform conversion guidelines to improve consistency and safety in the prescribing of opioids.

Keywords: analgesia; opioid; opioid analgesic; pain; palliative care.

MeSH terms

  • Administration, Oral
  • Australia
  • Consensus
  • Cross-Sectional Studies
  • Delayed-Action Preparations
  • Dose-Response Relationship, Drug
  • Drug Substitution*
  • Health Care Surveys
  • Humans
  • Infusions, Parenteral
  • Methadone / administration & dosage
  • Methadone / therapeutic use
  • Morphinans / administration & dosage*
  • Morphinans / pharmacokinetics
  • Narcotics / administration & dosage*
  • Narcotics / pharmacokinetics
  • Opiate Substitution Treatment
  • Pain Management / methods*
  • Palliative Care*
  • Practice Patterns, Physicians'*
  • Surveys and Questionnaires
  • Therapeutic Equivalency

Substances

  • Delayed-Action Preparations
  • Morphinans
  • Narcotics
  • Methadone