The physician ordered digoxin (Lanoxin) 0.125 mg IV push every morning. Digoxin is available in a vial labeled 0.5mg/2mL. How many mL with the nurse administer?
The Correct Answer and Explanation is:
To determine how many milliliters (mL) of digoxin the nurse should administer, follow these steps:
Calculation Steps
- Identify the Ordered Dosage and the Available Concentration:
- Ordered Dosage: 0.125 mg
- Available Concentration: 0.5 mg per 2 mL
- Calculate the Concentration per mL:
To find out how many milligrams are in 1 mL, divide the concentration by the volume:
[
\text{Concentration per mL} = \frac{0.5 \text{ mg}}{2 \text{ mL}} = 0.25 \text{ mg/mL}
] - Determine the Volume Needed to Administer the Ordered Dosage:
Use the concentration per mL to find the required volume to administer the ordered dosage:
[
\text{Volume required} = \frac{\text{Ordered Dosage}}{\text{Concentration per mL}} = \frac{0.125 \text{ mg}}{0.25 \text{ mg/mL}} = 0.5 \text{ mL}
]
Explanation
Digoxin is a cardiac glycoside used to treat various heart conditions, and it’s crucial to administer the correct dosage to avoid toxicity or insufficient therapeutic effect. The physician has ordered a dose of 0.125 mg of digoxin to be administered intravenously (IV) every morning.
The digoxin solution available is concentrated at 0.5 mg per 2 mL. To find the amount of solution that provides the prescribed dose, first determine how much drug is present in each mL of the solution. By dividing 0.5 mg by 2 mL, you find that each mL contains 0.25 mg of digoxin.
To achieve the ordered dose of 0.125 mg, you calculate how many milliliters are needed by dividing the ordered dose by the concentration per mL. This calculation shows that 0.5 mL of the available solution will provide the required 0.125 mg of digoxin.
Accurate dosing is critical in medication administration, especially with drugs like digoxin that have a narrow therapeutic range. This careful calculation helps ensure the patient receives the correct amount of medication, minimizing the risk of adverse effects and optimizing therapeutic outcomes.