NMC-CBT Drug Calculations and Numeracy Flashcards

An infusion pump alarm shows an occlusion after delivering 180 mL of a 500 mL bag. What percentage of the infusion has been delivered?

Answer: 36%

(180 ÷ 500) × 100 = 36%.

Codeine phosphate 30 mg/5 mL oral solution is prescribed at 60 mg four times daily. How many mL per day will the patient require?

Answer: 40 mL

60 mg dose = 10 mL; 10 × 4 = 40 mL per day.

A patient is to receive 20 mmol of potassium in 100 mL over 1 hour. The giving set delivers 20 drops/mL. What is the drip rate in drops/min?

Answer: 33 drops/min

(100 × 20) ÷ 60 = 2000 ÷ 60 ≈ 33 drops/min.

A nurse is checking a drug with a concentration of 2 mg in 1 mL. She needs to give 0.75 mg. How many mL should she draw up?

Answer: 0.375 mL

0.75 ÷ 2 = 0.375 mL.

A neonate weighing 3.2 kg is prescribed caffeine citrate 20 mg/kg as a loading dose. The solution is 10 mg/mL. How many mL are required?

Answer: 6.4 mL

Dose = 20 × 3.2 = 64 mg; volume = 64 ÷ 10 = 6.4 mL.

A patient's eGFR is 28 mL/min/1.73m². The nurse recognises this falls into which CKD stage requiring dose adjustment?

Answer: CKD Stage 4 (eGFR 15–29)

An eGFR of 28 mL/min/1.73m² falls within Stage 4 (15–29), requiring significant dose reductions for renally cleared drugs.

A ward stock bottle contains 2.5% w/v glucose solution. How many grams of glucose are present in 200 mL?

Answer: 5 g

2.5% w/v = 2.5 g per 100 mL; in 200 mL: 2.5 × 2 = 5 g.