Which of the following solution is only used for dilution of phenytoin (Dilantin)?

NORCET 5 Prelims - Sept 2023 (Shift-1)

Pharmacology

Easy

Appeared in: NORCET 5 Prelims - Sept 2023 (Shift-1)

Explanation

Phenytoin (Dilantin) is an anticonvulsant medication that has very specific requirements for intravenous administration.
It is only compatible with Normal Saline (NS, 0.9% Sodium Chloride).
NS maintains the proper pH and solubility for phenytoin, preventing it from crystallizing or precipitating out of the solution.
Using any other diluent can lead to loss of drug efficacy and poses a significant risk of embolism and vein damage to the patient.

Option B: Dextrose 5% (D5%) solutions have a lower pH that causes phenytoin to precipitate, forming crystals in the IV solution and tubing.
Option C: Ringer's Lactate (RL) is also incompatible with phenytoin and will cause it to precipitate.
Option D: A solution of D5% with Ringer's Lactate combines two fluids that are both incompatible with phenytoin, ensuring precipitation will occur.

Visual 1: Infographic - A side-by-side comparison showing a clear bag of phenytoin in Normal Saline versus a cloudy, precipitated mixture of phenytoin in D5W. The caption should state: 'Phenytoin in NS (Correct) vs. Phenytoin in D5W (Incorrect & Dangerous - Causes Precipitation).'
Visual 2: Flowchart - A decision-making flowchart for a nurse preparing to administer IV phenytoin. Steps would include: 1. Check physician's order. 2. Confirm drug allergies. 3. Select diluent -> 'Is it Normal Saline?' -> Yes -> Proceed. -> No -> STOP. Obtain Normal Saline.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain IV Medication Compatibility and Safety as background academic context rather than a clinical decision trigger.
Patient safety is the primary concern. Administering phenytoin in an incorrect diluent can lead to a life-threatening pulmonary embolism from the infused precipitate.
This is a critical 'must-know' fact for any nurse administering IV medications. An error can lead to severe patient harm and is considered a serious medication error.
What if? If a patient's primary IV infusion is D5W and they have an order for IV phenytoin, the nurse must pause the D5W infusion, flush the IV line vigorously with at least 10-20 mL of Normal Saline, administer the phenytoin (diluted in NS), flush again with Normal Saline, and only then restart the D5W infusion.

How to Approach the Question

First, identify the core of the question. It's asking for the specific, sole compatible diluent for the drug phenytoin.
This is a factual recall question based on pharmacological principles. There is no room for interpretation; there is only one correct answer.
Recall or look up the administration guidelines for high-risk or narrow-compatibility drugs like phenytoin.
Evaluate each option based on this knowledge. Remember the rule: 'Phenytoin precipitates in anything but saline.'
Eliminate all options containing dextrose (D5%) or other solutions like Ringer's Lactate.
Select Normal Saline (NS) as the only correct and safe option.

Concept Tested & Keywords

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