Order: Diphenhydramine 25mg Q4H
Available: Diphenhydramine 12.5mg/5mL
How much will you administer?
A.
2 mL
B.
10 mL
C.
25mL
D.
12.5 mL
The Correct answer and Explanation is:
To determine how much diphenhydramine to administer based on the order provided, we first need to assess the ordered dose and the concentration of the available solution.
Order
- Diphenhydramine: 25 mg
- Frequency: Every 4 hours (Q4H)
Available Concentration
- Diphenhydramine concentration: 12.5 mg per 5 mL
Step 1: Convert the available concentration to mg/mL
To understand how much medication is in each milliliter, we can set up the following calculation:Concentration (mg/mL)=12.5 mg5 mL=2.5 mg/mL\text{Concentration (mg/mL)} = \frac{12.5 \text{ mg}}{5 \text{ mL}} = 2.5 \text{ mg/mL}Concentration (mg/mL)=5 mL12.5 mg=2.5 mg/mL
Step 2: Calculate the volume needed for the ordered dose
Next, we can determine how many milliliters are needed to achieve the ordered dose of 25 mg using the concentration we just calculated:Volume (mL)=Ordered Dose (mg)Concentration (mg/mL)=25 mg2.5 mg/mL=10 mL\text{Volume (mL)} = \frac{\text{Ordered Dose (mg)}}{\text{Concentration (mg/mL)}} = \frac{25 \text{ mg}}{2.5 \text{ mg/mL}} = 10 \text{ mL}Volume (mL)=Concentration (mg/mL)Ordered Dose (mg)=2.5 mg/mL25 mg=10 mL
Conclusion
The calculation shows that in order to administer 25 mg of diphenhydramine, you would need to provide 10 mL of the available solution. Thus, the correct answer is:
B. 10 mL
Explanation of the Administration Process
When administering medications, it is crucial to verify the ordered dosage against what is available to ensure patient safety. Miscalculations can lead to underdosing, which may fail to alleviate the patient’s symptoms, or overdosing, which could result in adverse effects or toxicity. In this case, understanding the concentration of the diphenhydramine formulation allowed for accurate volume calculation, ensuring the patient receives the correct amount of medication as ordered. This approach is critical in nursing practice, where precise dosages can significantly impact patient outcomes. Always double-check calculations and consult with pharmacy resources when in doubt about medication administration.