The primary healthcare provider prescribes dopamine at 2.5 mcg/kg/min. The client weighs 198 lb. The label reads 800 mg in 500 mL of D5W. How many mL per hour will be administered?

• A. 6 mL/hr
• B. 8 mL/hr
• C. 10 mL/hr
• D. 12 mL/hr

Answer: (B)

When calculating an infusion rate for a weight-based drug, you convert weight to kilograms, compute the dose per hour, then use the solution’s concentration to find mL per hour.

First, convert the patient’s weight: 198 lb ÷ 2.2046 ≈ 89.8 kg (about 90 kg).

Next, find the dose per minute: 2.5 mcg/kg/min × 89.8 kg ≈ 224.5 mcg/min. Convert to per hour: 224.5 mcg/min × 60 ≈ 13,470 mcg/hr ≈ 13.5 mg/hr.

The solution concentration is 800 mg in 500 mL, which is 1.6 mg/mL = 1,600 mcg/mL.

Now convert to mL per hour: 13,470 mcg/hr ÷ 1,600 mcg/mL ≈ 8.42 mL/hr.

So the required infusion rate is about 8 mL/hr (the closest option).