A patient who weighs 154 pounds receives a prescription for epoetin alfa 50 units/kg subcutaneously 3 times a week. The medication is available in 2000 units/mL vial. How many mL should the nurse administer with each dose? (Enter numerical value only. If rounding is required, round to the nearest tenth.)
The Correct Answer and Explanation is:
To determine how many mL of epoetin alfa should be administered with each dose, follow these steps:
- Convert the patient’s weight from pounds to kilograms:
- Weight in pounds: 154 lbs
- Conversion factor: 1 pound = 0.453592 kilograms [
\text{Weight in kilograms} = 154 \text{ lbs} \times 0.453592 \text{ kg/lb} = 69.85 \text{ kg}
] For simplicity, we can round this to 70 kg.
- Calculate the total units of epoetin alfa required per dose:
- Dosage prescribed: 50 units/kg
- Patient’s weight: 70 kg [
\text{Total units per dose} = 50 \text{ units/kg} \times 70 \text{ kg} = 3500 \text{ units}
]
- Determine the volume of epoetin alfa solution needed:
- The medication concentration is 2000 units/mL. [
\text{Volume (mL)} = \frac{\text{Total units per dose}}{\text{Concentration (units/mL)}}
] [
\text{Volume (mL)} = \frac{3500 \text{ units}}{2000 \text{ units/mL}} = 1.75 \text{ mL}
]
So, the nurse should administer 1.8 mL of epoetin alfa per dose, rounded to the nearest tenth.
Explanation:
Epoetin alfa is a medication used to stimulate red blood cell production. It’s crucial to calculate the exact volume required to ensure the patient receives the correct dosage. This involves converting the patient’s weight into kilograms if it is provided in pounds, which is necessary for accurate dosing in metric units.
In this calculation, the total dosage is first determined by multiplying the weight (in kilograms) by the prescribed units per kilogram. This gives the total units needed for each dose. Next, knowing the concentration of the medication (2000 units per mL), the volume to be administered is calculated by dividing the total units by this concentration.
Ensuring the precise volume is essential for effective treatment and avoiding potential complications from underdosing or overdosing. Always round to the nearest tenth when the result is a decimal, to match standard practice in medication administration.