A pediatric patient requires 0.75 mg/kg/hr. The patient weighs 12 kg. The drug concentration is 2 mg/mL. What is the mL/hr?

• A. 9.0 mL/hr
• B. 2.25 mL/hr
• C. 4.5 mL/hr
• D. 6.0 mL/hr

Answer: (C)

To find the mL/hr, convert the prescribed rate to a dose per hour in mg, then turn that into volume using the concentration.

First, dose per hour = 0.75 mg/kg/hr × 12 kg = 9 mg/hr.

Since the solution is 2 mg/mL, the volume needed per hour is 9 mg/hr ÷ 2 mg/mL = 4.5 mL/hr.

So the patient should receive 4.5 mL per hour. This matches the required calculation: mg/hr divided by mg/mL gives mL/hr. The other numbers would come from using a different concentration or miscomputing the mg/hr.