Questions: A nurse is preparing to administer phenytoin 5 mg / kg / day PO divided equally every 12 hr for an infant who weighs 12 lb 4 oz. How many mg should the nurse administer per dose? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.) mg

Solution Steps

To solve this problem, we need to follow these steps:

1. Convert the infant's weight from pounds and ounces to kilograms.
2. Calculate the total daily dosage in milligrams using the given dosage per kilogram.
3. Divide the total daily dosage by the number of doses per day to find the dosage per administration.

First, we convert the infant's weight from pounds and ounces to kilograms. Given:

• \( \text{pounds} = 12 \)
• \( \text{ounces} = 4 \)

We know that:

• \( 1 \text{ pound} = 16 \text{ ounces} \)
• \( 1 \text{ ounce} = 0.02835 \text{ kilograms} \)

So, the total weight in ounces is: \[ \text{total\_ounces} = 12 \times 16 + 4 = 196 \text{ ounces} \]

Then, convert the total ounces to kilograms: \[ \text{weight\_kg} = 196 \times 0.02835 = 5.5565 \text{ kg} \]

The dosage prescribed is \( 5 \text{ mg/kg/day} \). Therefore, the total daily dosage in milligrams is: \[ \text{total\_daily\_dosage\_mg} = 5 \times 5.5565 = 27.7825 \text{ mg} \]

The medication is to be administered every 12 hours, which means there are 2 doses per day. Thus, the dosage per administration is: \[ \text{dosage\_per\_dose\_mg} = \frac{27.7825}{2} = 13.8913 \text{ mg} \]

Rounding to the nearest tenth: \[ \text{dosage\_per\_dose\_mg} \approx 13.9 \text{ mg} \]

Final Answer