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SC Morphine to SC Oxycodone Ratio — SCE Palliative Medicine MCQ

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EasySyringe Driver & Drug CompatibilitySC Morphine to SC Oxycodone RatioSCE Palliative Medicine

Using the approximate conversion in the Scottish Palliative Care Guidelines, a patient with stable pain control is being switched from morphine 60 mg/24 hours by subcutaneous continuous infusion to oxycodone by the same route. What is the approximate equianalgesic 24-hour dose of subcutaneous oxycodone before any reduction for incomplete cross-tolerance?

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Correct answer: E — Oxycodone 30 mg/24 hours by subcutaneous continuous infusion

The correct answer is E. The Scottish Palliative Care Guidelines give subcutaneous morphine 30 mg as approximately equivalent to subcutaneous oxycodone 15 mg. Thus, for the same 24-hour route, 60 × 15/30 = 30 mg of subcutaneous oxycodone over 24 hours. This is the approximate equianalgesic calculation only. A subsequent reduction may be appropriate because of incomplete cross-tolerance or if the patient is frail, opioid-toxic or otherwise at increased risk, but that reduction must not be built into the conversion requested here. Option C represents a 1:1 conversion used in some product information, illustrating why the source is specified. Option A applies an excessive reduction, option D reverses the potency relationship, and option B uses an inapplicable conversion factor.

Reference: Healthcare Improvement Scotland, Scottish Palliative Care Guidelines, “Oxycodone”, Dose conversions, current online guidance accessed 25 July 2026. https://www.rightdecisions.scot.nhs.uk/shared-content/palliative-care/palliative-care/oxycodone/?searchTerm=seizure