The PHCP prescribes 500 mg of intravenous metronidazole to be administered over thirty minutes. The bag contains 500 mg of metronidazole in 100 mL of 0.9% saline. How many mL/hour should be infused?

The PHCP prescribes 500 mg of intravenous metronidazole to be administered over thirty minutes. The bag contains 500 mg of metronidazole in 100 mL of 0.9% saline. How many mL/hour should be infused?

• A. 100 mL/hr
• B. 150 mL/hr
• C. 200 mL/hr
• D. 250 mL/hr

Answer: (C)

Infusion rate equals the total volume to be infused divided by the infusion time. Here the bag is 100 mL and must be given over 30 minutes (0.5 hours). So the rate is 100 mL / 0.5 h = 200 mL per hour. The concentration (500 mg in 100 mL) confirms the dose, but for the rate you only use volume and time. Therefore, the infusion should run at 200 mL/hour.

Infusion rate equals the total volume to be infused divided by the infusion time. Here the bag is 100 mL and must be given over 30 minutes (0.5 hours). So the rate is 100 mL / 0.5 h = 200 mL per hour. The concentration (500 mg in 100 mL) confirms the dose, but for the rate you only use volume and time. Therefore, the infusion should run at 200 mL/hour.