The prescribed rate is 0.05 mg/kg/min. If the patient weighs 20 kg and the drug concentration is 0.5 mg/mL, what is the infusion rate in mL per minute?

The prescribed rate is 0.05 mg/kg/min. If the patient weighs 20 kg and the drug concentration is 0.5 mg/mL, what is the infusion rate in mL per minute?

• A. 2 mL/min
• B. 0.5 mL/min
• C. 1 mL/min
• D. 4 mL/min

Answer: (A)

When calculating IV infusion rates, convert the prescribed dose into a mass flow per minute first, then turn that mass flow into a volume flow using the solution’s concentration. Start with the weight-based rate: 0.05 mg/kg/min times 20 kg equals 1 mg per minute. Then use the concentration to convert to milliliters: 1 mg/min divided by 0.5 mg/mL equals 2 mL per minute. So, the infusion rate is 2 mL/min.

When calculating IV infusion rates, convert the prescribed dose into a mass flow per minute first, then turn that mass flow into a volume flow using the solution’s concentration.

Start with the weight-based rate: 0.05 mg/kg/min times 20 kg equals 1 mg per minute.

Then use the concentration to convert to milliliters: 1 mg/min divided by 0.5 mg/mL equals 2 mL per minute.

So, the infusion rate is 2 mL/min.