Phenytoin has a narrow therapeutic index.
The nurse recognizes that this characteristic indicates which of these?

The safe and the toxic plasma levels of the drug are very close to each other.

The phenytoin has a low chance of being effective.

There is no difference between safe and toxic plasma levels.

A very small dosage can result in the desired therapeutic effect.

Answer and Explanation

The Correct Answer is A

Choice A rationale:

Phenytoin is an anticonvulsant drug used in the prophylaxis and control of various types of seizures. It has a narrow therapeutic index, which means that the safe and toxic plasma levels of the drug are very close to each other. This characteristic makes the dosing of phenytoin challenging, as even small deviations from the recommended therapeutic range can lead to suboptimal treatment or adverse effects. Therapeutic effect without clinical signs of toxicity occurs more often with serum total concentrations between 10 and 20 mcg/mL34. Therefore, clinicians are advised to initiate therapeutic drug monitoring in patients who require phenytoin.

Choice B rationale:

The statement that phenytoin has a low chance of being effective is incorrect. Phenytoin is a widely used and effective anticonvulsant. It works by slowing down impulses in the brain that cause seizures. It is used to control seizures but does not treat all types of seizures. The effectiveness of phenytoin is not determined by its narrow therapeutic index but by its pharmacological action in the brain.

Choice C rationale:

The assertion that there is no difference between safe and toxic plasma levels of phenytoin is incorrect. There is indeed a difference between the safe (therapeutic) and toxic levels of phenytoin. The therapeutic range for phenytoin is typically between 10 and 20 mcg/mL34. Levels above this range can lead to toxicity, while levels below this range may not provide the desired therapeutic effect.

Choice D rationale:

The statement that a very small dosage of phenytoin can result in the desired therapeutic effect is not entirely accurate. While it’s true that phenytoin is effective in controlling seizures, the dosage required to achieve this effect is not necessarily “very small”. The usual adult dose for seizures is 100 mg orally 3 times a day. The dosage may need to be adjusted based on individual patient factors and response to therapy. Therefore, it’s not accurate to generalize that a “very small” dosage will result in the desired therapeutic effect for all patients.

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Correct Answer is C

Explanation

Choice A rationale:

Erythromycin Erythromycin is a macrolide antibiotic that is often used as an alternative to penicillin. It is generally safe for use in patients with a penicillin allergy. It works by inhibiting bacterial protein synthesis and is effective against a wide range of bacteria.

Choice B rationale:

Amphotericin B Amphotericin B is an antifungal medication, not an antibiotic. It is used to treat serious, systemic fungal infections. It has no cross-reactivity with penicillin, so it would not be a concern for a patient with a penicillin allergy.

Choice C rationale:

Amoxicillin-clavulanate Amoxicillin-clavulanate is a type of penicillin antibiotic. Patients with a known penicillin allergy should avoid this medication, as they may have a cross-reactivity to it. This is why the nurse should verify this prescription with the provider.

Choice D rationale:

Gentamicin Gentamicin is an aminoglycoside antibiotic used to treat serious bacterial infections caused by gram-negative bacteria. It is not related to penicillin and would be safe for a patient with a penicillin allergy.

A. Report the near-miss using the facility’s recommended protocol, and correct the error on the MAR B. Report the near-miss to the next shift before the next dose is due C. Correct the MAR error but say nothing because nothing happened D. Notify the pharmacy about the error they almost caused .

Correct Answer is A

Explanation

Choice A rationale:

Reporting a near-miss using the facility’s recommended protocol and correcting the error on the MAR is the appropriate action. A “near-miss” in healthcare is a situation where an error could have happened, but didn’t, either by chance or timely intervention. It’s crucial to report these incidents as they provide valuable information for risk management and quality improvement. By analyzing near-misses, healthcare facilities can identify potential hazards and take preventive measures to ensure patient safety. Correcting the error on the MAR is also important to prevent the same mistake from happening in the future.

Choice B rationale:

Reporting the near-miss to the next shift before the next dose is due is not the best course of action. While it’s important to communicate any potential issues to the next shift, it’s more crucial to report the incident immediately using the facility’s recommended protocol. This allows for a timely investigation and corrective action. Waiting until the next shift could delay these processes and potentially put patient safety at risk.

Choice C rationale:

Correcting the MAR error but saying nothing because nothing happened is not an appropriate response. Even though the error did not result in any harm, it’s still important to report it. Near-misses are often indicators of underlying system issues that need to be addressed. By not reporting the incident, the opportunity to improve patient safety and prevent future errors is lost.

Choice D rationale:

Notifying the pharmacy about the error they almost caused is not the most appropriate action. While it’s important to communicate with the pharmacy if they were involved in the error, the first step should always be to report the near-miss using the facility’s recommended protocol. This ensures that the incident is properly documented and investigated, and that appropriate corrective actions are taken.

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Phenytoin has a narrow therapeutic index. The nurse recognizes that this characteristic indicates which of these?

Nursing Test Bank

Naxlex Comprehensive Predictor Exams

A nurse is caring for a child who has a penicillin allergy. Which of the following prescriptions should the nurse verify with the provider?

Correct Answer is C

Explanation

During morning medication administration, the nurse discovered an error on the electronic Medication Administration Record (MAR) before the medication was given. What is the appropriate action for this “near-miss”?

Correct Answer is A

Explanation

During antibiotic therapy, the nurse will monitor closely for signs and symptoms of a hypersensitivity reaction. Which of these assessment findings may be an indication of a hypersensitivity reaction? (Select all that apply.)

When teaching a patient a skill such as self-injection of insulin, what is the best way to set up the teaching/learning session?

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A nurse is preparing to administer methylnaltrexone 12 mg subcutaneously to a client who has opioid-induced constipation. The available methylnaltrexone is 8 mg/0.4 mL. How many mL should the nurse administer? (Round the answer to the nearest tenth. Use a leading zero if it applies.

A nurse is collecting data from a client who has diabetes mellitus. Which of the following findings indicates that the client is experiencing DKA?

A nurse is caring for a client who has recurrent kidney stones and a history of diabetes mellitus. The client is scheduled for an intravenous Pyelogram (IVP). The nurse should collect additional data about which of the following statements made by the client?

A 6-year-old child who has chickenpox also has a fever of 102.9 F (39.4 C). The child’s mother asks the nurse if she should use aspirin to reduce the fever. What is the best response by the nurse?

When a patient is undergoing aminoglycoside therapy, which indicators should the nurse monitor for potential toxicity?

Phenytoin has a narrow therapeutic index.
The nurse recognizes that this characteristic indicates which of these?