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Syringe Size Selection for High Drug Loads — SCE Palliative Medicine MCQ

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ModerateSyringe Driver & Drug CompatibilitySyringe Size Selection for High Drug LoadsSCE Palliative Medicine

A dying patient requires a 24‑hour continuous subcutaneous infusion (CSCI) delivering morphine 120 mg, midazolam 40 mg, and glycopyrronium 2.4 mg. The total volume of these drugs before dilution is 9.2 mL. What is the minimum recommended syringe size?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — 20 mL or 30 mL syringe to allow adequate dilution; higher drug concentrations in smaller syringes increase site reaction risk

UK palliative care syringe‑driver policies explicitly endorse using 20 mL or 30 mL syringes to allow adequate dilution when mixing multiple drugs and warn that smaller syringes may increase site reactions. The 10 mL syringe is too small for ~9.2 mL of drug and gives inadequate dilution. A 5 mL syringe is impractical and unsafe for 24‑hour infusions. A 50 mL syringe exceeds minimum needs and requires specialist handling. Saying size is irrelevant ignores clear UK guidance on dilution to reduce irritation.

Reference: RDaSH SOP on syringe driver administration (2024), Lancashire & South Cumbria Palliative Care Prescribing Guidelines (2014), Scottish Palliative Care Guidelines BodyGuard T Protocol (2023), https://www.england.nhs.uk/north/wp-content/uploads/sites/5/2018/06/Palliative_Care_Prescribing_Guidelines_-_May_2014_Blackpool.pdf