An order is received for Principen (ampicillin) 25 mg/kg IV for a toddler who weighs 22 lb. The dose is to be infused over 30 minutes. The ampicillin dose arrives from the pharmacy prepared in 50 mL of solution.
How many milliliters per hour should be administered?
25 mL/hr
50 mL/hr
100 mL/hr
10 mL/hr
The Correct Answer is C
To find the milliliters per hour, you need to calculate the following:
- The patient's weight in kilograms
- The dose of Principen in milligrams
- The infusion rate in milliliters per hour using the formula: Infusion rate (mL/h) = (Total volume (mL) x Flow factor (gt/mL)) / Time (min) x 60 min/h
First, convert the patient's weight from pounds to kilograms by dividing by 2.2:
22 lb / 2.2 = 10 kg
Next, multiply the patient's weight by the dose of Principen per kilogram to get the total dose in milligrams:
10 kg x 25 mg/kg = 250 mg
Then, use the formula for infusion rate to find how many milliliters per hour the IV pump should deliver:
Infusion rate (mL/h) = (Total volume (mL) x Flow factor (gt/mL)) / Time (min) x 60 min/h
Since the medication is prepared in 50 mL of solution and the infusion time is 30 minutes, plug in these values into the formula:
Infusion rate (mL/h) = (50 mL x 1 gt/mL) / 30 min x 60 min/h
Simplify and solve for the infusion rate:
Infusion rate (mL/h) = 100 mL/h
Therefore, the nurse should administer **100 mL/h** to infuse Principen 250 mg over 30 minutes.

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Related Questions
Correct Answer is D
Explanation
To calculate the rate of infusion, we need to divide the total volume to be infused (1.5 L) by the total time of infusion (24 hours)
1.5 L = 1500 mL (since 1 L = 1000 mL)
Dividing 1500 mL by 24 hours gives us the rate of 62.5 mL/hr.
Correct Answer is A
Explanation
To set the IV pump correctly, you need to calculate the following:
- The patient's weight in kilograms
- The dose of Zofran in milligrams
- The infusion rate in milliliters per hour
First, convert the patient's weight from pounds to kilograms by dividing by 2.2:
176 lb / 2.2 = 80 kg
Next, multiply the patient's weight by the dose of Zofran per kilogram to get the total dose in milligrams:
80 kg x 0.15 mg/kg = 12 mg
Then, use the formula for infusion rate to find how many milliliters per hour the IV pump should deliver:
Infusion rate (mL/h) = (Total volume (mL) x Flow factor (gt/mL)) / Time (min) x 60 min/h
Since the medication is mixed in 50 mL of normal saline and the infusion time is 15 minutes, plug in these values into the formula:
Infusion rate (mL/h) = (50 mL x 1 gt/mL) / 15 min x 60 min/h
Simplify and solve for the infusion rate:
Infusion rate (mL/h) = 200 mL/h
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