For a dopamine infusion ordered at 8 mcg/kg/min for an 86 kg patient with a concentration of 1600 mcg/mL, what is the dose in mcg/min?

For a dopamine infusion ordered at 8 mcg/kg/min for an 86 kg patient with a concentration of 1600 mcg/mL, what is the dose in mcg/min?

• A. 344 mcg/min
• B. 688 mcg/min
• C. 860 mcg/min
• D. 172 mcg/min

Answer: (B)

Dosing a drug by weight per time means you multiply the prescribed rate by the patient’s weight to get the total amount given each minute. Here, 8 mcg/kg/min times 86 kg equals 688 mcg per minute. The concentration (1600 mcg/mL) isn’t needed to find the mcg/min dose; it would be used if you had to convert the infusion to mL per minute (0.43 mL/min, roughly 25.8 mL/hour). So the correct dose is 688 mcg/min.

Dosing a drug by weight per time means you multiply the prescribed rate by the patient’s weight to get the total amount given each minute. Here, 8 mcg/kg/min times 86 kg equals 688 mcg per minute. The concentration (1600 mcg/mL) isn’t needed to find the mcg/min dose; it would be used if you had to convert the infusion to mL per minute (0.43 mL/min, roughly 25.8 mL/hour). So the correct dose is 688 mcg/min.