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Conversion of other opioids to methadone: a retrospective comparison of two methods
  1. Bill Lukin1,
  2. Jaimi Greenslade1,2,
  3. Alison Mary Kearney3,4,5,
  4. Carol Douglas3,4,
  5. Tegwen Howell5,
  6. Michael Barras6,7 and
  7. Phillip Good8,9,10
  1. 1 Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
  2. 2 Australian Centre for Health Services Innovation, School of Public Health and Social Work, Queensland University of Technology, Brisbane, Queensland, Australia
  3. 3 Department of Palliative and Supportive Care, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
  4. 4 University of Queensland, Brisbane, Queensland, Australia
  5. 5 Queensland Emergency Medicine Foundation, Milton, Queensland, Australia
  6. 6 Pharmacy Department, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
  7. 7 School of Pharmacy, University of Queensland, Brisbane, Queensland, Australia
  8. 8 Department of Supportive and Palliative Care, Mater Health Services, Brisbane, Queensland, Australia
  9. 9 Department of Palliative Care, St Vincent's Private Hospital, Brisbane, Queensland, Australia
  10. 10 Mater Research Institute, University of Queensland, Brisbane, Queensland, Australia
  1. Correspondence to Dr Phillip Good, Department of Palliative Care, St Vincent's Private Hospital, Brisbane, QLD 4169, Australia; Phillip.Good{at}


Context A rapid method of methadone conversion known as the Perth Protocol is commonly used in Australian palliative care units. There has been no follow-up or validation of this method and no comparison between different methods of conversion.

Objectives The primary objective of this study was to test the hypothesis that the achieved doses of methadone are independent of the conversion method (rapid vs slower). The secondary objectives included examining the relationship between calculated target doses, actual achieved doses and duration of conversions.

Methods This is a retrospective chart audit conducted at two hospital sites in the Brisbane metropolitan area of Australia which used different methadone conversion methods.

Results Methadone conversion ratios depended on previous opioid exposure and on the method of conversion used. The method most commonly used in Australia for calculating target doses for methadone when converting from strong opioids is a poor predictor of actual dose achieved. More appropriate conversion ratios are suggested.

Conclusion Further research is needed to refine the ratios used in practice when converting patients from strong opioids to methadone. Caution and clinical expertise are required. A palliative methadone registry may provide useful insights.

  • conversion method
  • methadone
  • analgesia
  • palliative care

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  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Ethics approval was obtained at both sites.

  • Provenance and peer review Not commissioned; externally peer reviewed.