A medication has a concentration of 1 mg/mL. The order is 0.75 mg/min. What is the infusion rate in mL/min?

• A. 0.75 mL/min
• B. 0.5 mL/min
• C. 1.0 mL/min
• D. 1.5 mL/min

Answer: (A)

Infusion rate is found by converting the prescribed dose per minute into a volume per minute using the solution’s concentration. The relationship is: rate (mL/min) = dose rate (mg/min) ÷ concentration (mg/mL).

Here, 0.75 mg/min ÷ 1 mg/mL = 0.75 mL/min. So the infusion rate is 0.75 mL per minute. If the concentration were higher, the rate would have to be smaller to deliver the same mg/min, and if it were lower, the rate would be larger.