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Loading Dose When Starting CSCI — SCE Palliative Medicine MCQ

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ModerateSyringe Driver & Drug CompatibilityLoading Dose When Starting CSCISCE Palliative Medicine

A patient on oral morphine 90 mg/24 hours needs emergency conversion to CSCI because of sudden complete dysphagia from oesophageal cancer progression. She has no IV access. The community nurse is setting up the CSCI within 30 minutes. What should be done regarding loading?

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Correct answer: D — Give an appropriate SC rescue dose while the CSCI starts

The correct answer is D. When urgently switching a patient from oral to subcutaneous morphine via syringe driver (CSCI), a loading (breakthrough) dose of 1/6th of the 24-hour CSCI dose (here, 45 mg/6 = 7.5 mg SC morphine) should be given immediately. This accounts for delayed attainment of steady-state concentrations with continuous infusion and avoids undertreatment of pain while the CSCI is establishing. Option C (giving 24-hour dose SC at once) causes dangerous opioid toxicity. Option B is not feasible (no IV access, not needed). Option A (withholding PRN) risks pain crisis. Option E neglects pharmacokinetic realities: analgesic effect from CSCI builds slowly. UK palliative care guidelines explicitly recommend a 1/6th PRN SC dose as a loading strategy upon CSCI initiation.

Reference: South West Bedfordshire NHS Trust, Anticipatory Medication Clinical Guidelines, 2023, p. 17. https://www.swbh.nhs.uk/wp-content/uploads/2024/08/Anticipatory-Medication-Clinical-Guidelines-UPdate-2023-external-version-v2.pdf