The physician orders vancomycin 500 mg in 250 mL of D5W IVPB daily to infuse over 2 hours. Tubing drop factor is 15 gtts/mL. Calculate the flow rate in drops per minute.

Step 1 is 2 hours × 60 minutes = 120 minutes. Step 2 is (250 mL ÷ 120 minutes) × 15 gtts/mL. Step 3 is 2.08333 mL/min × 15 gtts/mL = 31.24995 gtts/min. Step 4 is 31.24995 rounded to the nearest whole number is 31. The final calculated answer is 31 gtts/min.