A nurse is preparing to administer digoxin 7.5 mcg/kg/day PO daily to a school-age child who weighs 52 lb. Available is digoxin elixir 50 mcg/mL. How many mL 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.)
The correct answer and Explanation is :
To calculate the amount of digoxin the nurse should administer, follow these steps:
- Convert the child’s weight from pounds to kilograms:
Since 1 kilogram (kg) = 2.2 pounds (lb), divide the child’s weight in pounds by 2.2. [
\text{Weight in kg} = \frac{52 \, \text{lb}}{2.2} = 23.64 \, \text{kg}
] - Calculate the total daily dose in micrograms (mcg):
The order is for 7.5 mcg per kg of body weight per day. Multiply the child’s weight in kg by the dosage (7.5 mcg/kg/day). [
\text{Dose} = 7.5 \, \text{mcg/kg/day} \times 23.64 \, \text{kg} = 177.3 \, \text{mcg/day}
] - Determine the volume to administer:
The available digoxin elixir is 50 mcg/mL. To find the volume of elixir needed, divide the total dose by the concentration of the elixir. [
\text{Volume} = \frac{177.3 \, \text{mcg}}{50 \, \text{mcg/mL}} = 3.546 \, \text{mL}
] - Round the answer to the nearest tenth:
[
3.546 \, \text{mL} \approx 3.5 \, \text{mL}
]
Thus, the nurse should administer 3.5 mL of digoxin.
Explanation:
This problem is an example of medication dosage calculation, which is essential in pediatric nursing because children’s doses must be carefully tailored to their weight to avoid under- or overdosing. The weight in pounds is first converted to kilograms, as medications are typically dosed per kilogram. The total daily dose is calculated based on the prescribed mcg/kg/day. Finally, the nurse uses the concentration of the elixir to figure out how much liquid medication (in mL) is required. The calculation must be precise, and rounding is done only at the last step to ensure accuracy while maintaining safety standards.