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Difficulty: HardPharmacological and Parenteral Therapies

A nurse is preparing to administer an initial loading dose of 10001000 mg of intravenous phenytoin to an adult client experiencing continuous seizure activity. The client has a single peripheral intravenous catheter currently infusing 5% dextrose in water (D5W) at 100100 mL/hr. Which sequence of actions is the most appropriate for safe parenteral administration of this medication?

  1. A
    Connect the medication syringe to the lowest Y-site of the primary tubing and administer the medication concurrently with the infusing dextrose solution over 2020 minutes.
  2. B
    Dilute the 10001000 mg of phenytoin into a 250250 mL bag of 5% dextrose in water and administer it as a secondary intermittent infusion.
  3. C
    Pause the primary dextrose infusion, flush the line with 0.9% sodium chloride, administer the phenytoin rapidly over 55 minutes to quickly halt the seizure, and flush again.
  4. Pause the primary dextrose infusion, flush the line with 0.9% sodium chloride, administer the phenytoin over at least 2020 minutes, and flush again with 0.9% sodium chloride.Answer

Answer

The most appropriate action is to pause the primary dextrose infusion, flush the line with 0.9% sodium chloride, administer the phenytoin over at least 2020 minutes, and flush again with 0.9% sodium chloride.
The correct approach comprehensively addresses both the chemical incompatibility of the medication and its strict administration rate limit. Phenytoin rapidly precipitates in dextrose solutions, meaning the existing D5W infusion must be paused and the line thoroughly flushed with 0.9% sodium chloride both before and after the dose. Furthermore, intravenous phenytoin must not be administered faster than 5050 mg/minute in adults. For a 10001000 mg loading dose, the absolute minimum administration time is 2020 minutes (10001000 mg / 5050 mg/minute) to minimize the risk of cardiovascular collapse and severe hypotension.

Step-by-Step Solution

1
Identify the primary medication incompatibility.
Phenytoin physically precipitates when mixed with 5% dextrose in water (D5W).
Recognizing drug-solution incompatibility is crucial to prevent line occlusion and the infusion of solid crystalline emboli.
2
Determine the necessary intravenous line management strategy.
The primary D5W infusion must be paused and the line completely flushed with 0.9% sodium chloride before and after the medication is given.
0.9% sodium chloride is physically compatible with phenytoin and clears the line of any residual dextrose.
3
Calculate the safe maximum administration rate.
Dividing the 10001000 mg dose by the maximum safe rate of 5050 mg/minute yields a minimum required infusion time of 2020 minutes.
Rapid intravenous administration of phenytoin can cause severe hypotension, severe bradycardia, and fatal cardiovascular collapse.

Key Concept

Intravenous Phenytoin Administration, Fluid Compatibility, and Rate Calculation

Alternative Method

Nurses may utilize an intravenous pump to deliver the medication over 2020 to 3030 minutes rather than a manual IV push, provided the primary line is flushed and verified to contain only 0.9% sodium chloride.
Estimated Time:2m 0s
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Topics

Pharmacological and Parenteral Therapies

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