A prescriber orders enoxaparin 40 mg subcutaneously once daily for 30 days. The pharmacy stocks single-dose prefilled syringes containing 40 mg in 0.4 mL and also stocks empty 1 mL insulin syringes and 3 mL Luer-lock syringes. The patient will self-administer at home and has no dexterity problems. Which dispensing choice best matches the order while minimising measurement error?
- ADispense 30 prefilled 40 mg/0.4 mL syringes, one per day Correct
- BDispense a multidose vial and thirty 1 mL insulin syringes graduated in units
- CDispense a multidose vial and thirty 3 mL Luer-lock syringes
- DDispense fifteen prefilled 40 mg/0.4 mL syringes with instructions to use half each day
Why A is correct: Correct: a single-dose prefilled syringe delivers the exact 40 mg ordered with no patient measurement, which is the safest match for a once-daily 30-day home supply.
Why B is wrong: Tempting because insulin syringes are common at home, but they are graduated in insulin units, not millilitres, so they cannot reliably measure a 0.4 mL enoxaparin dose.
Why C is wrong: Tempting because a 3 mL syringe can hold the dose, but its large graduations make a precise 0.4 mL measurement hard, and a prefilled product already exists for this drug.
Why D is wrong: Tempting as a cost-saving idea, but prefilled single-dose syringes are not designed to be split, and halving them gives 20 mg, not the ordered 40 mg.