A physician orders 40 mg of a medication IVPB to be diluted in 100 mL of D5W and administered over 2 hours. If the tubing delivers 60 drops/mL, a nurse should regulate the infusion to run at how many drops/minute?

• A. 20
• B. 50
• C. 100
• D. 120

Answer: (B)

Infusion rate is determined by how much fluid is delivered per unit time, then converted to drops per minute using the tubing’s drop factor. The total volume is 100 mL to be infused over 2 hours, so the flow is 100 mL / 2 h = 50 mL per hour. With a drop factor of 60 drops per mL, the rate becomes 50 mL/hr × 60 drops/mL = 3000 drops per hour. Converting to minutes: 3000 drops/hr ÷ 60 min/hr = 50 drops per minute. The dose amount (40 mg) isn’t needed to calculate the infusion rate here. Therefore, set the infusion to 50 drops per minute.