Nokea
Phenytoin has a narrow therapeutic index. The nurse recognizes that this characteristic indicates which of these?
- A. The safe and the toxic plasma levels of the drug are very close to each other.
- B. The phenytoin has a low chance of being effective.
- C. There is no difference between safe and toxic plasma levels.
- D. A very small dosage can result in the desired therapeutic effect.
Correct Answer: A
Rationale: Having a narrow therapeutic index means that there is a small difference between safe and toxic drug levels. These drugs require monitoring of therapeutic plasma levels. The other options are incorrect.
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The nurse has given medication instructions to a patient receiving phenytoin. Which statement by the patient indicates that the patient has an adequate understanding of the instructions?
- A. I will need to take extra care of my teeth and gums while on this medication.
- B. I can go out for a beer while on this medication.
- C. I can skip doses if the side effects bother me.
- D. I will be able to stop taking this drug once the seizures stop.
Correct Answer: A
Rationale: Good dental care is necessary to prevent gingival hypertrophy during therapy with phenytoin. Alcohol and other central nervous system depressants may cause severe sedation. Consistent dosing is important to maintain therapeutic drug levels. Therapy with AEDs usually must continue for life and must not be stopped once seizures stop.
A patient has a 9-year history of a seizure disorder that has been managed well with oral phenytoin therapy. He is to be NPO (consume nothing by mouth) for surgery in the morning. What will the nurse do about his morning dose of phenytoin?
- A. Give the same dose intravenously.
- B. Give the morning dose with a small sip of water.
- C. Contact the prescriber for another dosage form of the medication.
- D. Notify the operating room that the medication has been withheld.
Correct Answer: C
Rationale: If there are any questions about the medication order or the medication prescribed, contact the prescriber immediately for clarification and for an order of the appropriate dose form of the medication. Do not change the route without the prescriber's order. There is an increased risk of seizure activity if one or more doses of the AED are missed.
The nurse is reviewing the dosage schedule for several different antiepileptic drugs (AEDs). Which antiepileptic drug allows for once-a-day dosing?
- A. Levetiracetam
- B. Phenobarbital
- C. Valproic acid
- D. Gabapentin
Correct Answer: B
Rationale: Phenobarbital has the longest half-life of all standard AEDs, including those listed in the other options; therefore, it allows for once-a-day dosing.
The nurse is reviewing antiepileptic drug (AED) therapy. Which statements about AED therapy are accurate?
- A. AED therapy can be stopped when seizures are stopped.
- B. AED therapy is usually lifelong.
- C. Consistent dosing is the key to controlling seizures.
- D. A dose may be skipped if the patient is experiencing adverse effects.
- E. Abruptly stopping AEDs may cause rebound seizure activity.
Correct Answer: B,C,E
Rationale: Patients need to know that AED therapy is usually lifelong, and compliance (with consistent dosing) is important for effective seizure control. Abruptly stopping AED therapy may cause withdrawal (or rebound) seizure activity.
A 9-year-old child will be receiving carbamazepine suspension, 200 mg twice daily. The medication is available in a strength of 100 mg/5 mL. Identify how many milliliters the nurse will give to the patient for each dose.
Correct Answer: 10 mL
Rationale: 100 mg : 5 mL :: 200 mg : x mL; (100 * x) = (5 * 200); 100x = 1000; x = 10 mL/dose.