Medication Calculation and Administration Check
You are asked to administer 750 mg of paracetamol IV to an adult patient weighing 82 kg. The stock available is a 1000 mg/100 mL infusion bag. The prescription is written as 'Paracetamol 750 mg IV over 15 minutes'. The patient also has a prescription for regular oral paracetamol 1 g four times daily, last given 3 hours ago. The patient reports feeling hot and has a temperature of 38.1°C. Your colleague says, 'Just give the whole bag, it's close enough.'
1. Calculate the volume to administer and identify the safety concerns in this prescription.
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Calculation: 1000 mg in 100 mL → 1 mg = 0.1 mL → 750 mg = 75 mL. Administer 75 mL, not the full 100 mL.
Safety concerns: (1) Duplicate therapy - the patient is already on regular oral paracetamol 1 g four times daily, last dose 3 hours ago. Adding 750 mg IV risks exceeding the maximum daily dose (commonly 4 g/day in adults, lower in hepatic impairment or low body weight). Check the total 24-hour cumulative dose before giving any additional paracetamol. (2) 'Close enough' is not acceptable - giving 1000 mg instead of 750 mg is a dosing error and compounds the cumulative-dose risk. (3) Infusion rate - 15 minutes for 75 mL must be set accurately; too fast risks adverse effects. (4) Prescription clarity - confirm the indication (fever) and whether the regular oral dose should be withheld or adjusted.
Action: do not administer until the cumulative dose and duplication are clarified with the prescriber or pharmacist. Document the check and the decision.
2. What is the correct checking and administration process, and what would you do if the prescriber could not be reached?
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Process: follow the local medication administration rights - right patient (ID band, two identifiers), right drug, right dose (recalculate independently), right route, right time, right documentation, and right to refuse. Have a second checker verify the calculation and the cumulative dose where policy requires. Check allergies, expiry, and compatibility. Administer at the prescribed rate using an infusion pump, monitor the patient, and document dose, time, route, batch and response.
If prescriber unreachable: do not give the dose on assumption. Withhold the additional paracetamol, continue monitoring (temperature, comfort, hydration), and use non-pharmacological measures within your scope. Escalate to the nurse in charge or pharmacist for advice on the duplicate prescription. Document the omission, the reason, and the escalation. Reassess and report any deterioration.
Key principle: when in doubt, do not administer - a delay with monitoring is safer than a dosing error, and every omission or delay must be documented and communicated.