Pharmacology Seizure meds #8

Question

The nurse is teaching a client on toxicity while taking phenytoin sodium. The nurse determines the teaching is successful after the client describes which of the following should be reported to the health provider? Select all that apply.

Answers

  1. Hyperactivity
    • Rationale:

      This answer is not correct because lethargy (not hyperactivity) is most associated with phenytoin toxicity. Other CNS effects, such as visual disturbances, nystagmus, slurring speech, coma, or death are associated with phenytoin toxicity. Blood levels should be monitored and maintained at 10-20 mcg/mL to prevent toxicity symptoms.

  2. Diplopia
    • Rationale:

      This answer is correct because toxic side effects of phenytoin therapy include visual disturbances, such as diplopia (double vision). Additional toxic side effects include nystagmus, slurring speech, lethargy, coma, or death. Blood levels should be monitored and maintained at 10-20 mcg/mL to prevent toxicity symptoms.

  3. Bruising
    • Rationale:

      This answer is not correct because bruising is not associated with phenytoin. Bruising would be most associated with high blood levels of anticoagulants or antiplatelets. Toxic side effects of phenytoin include visual disturbances, nystagmus, slurring speech, lethargy, coma, or death. Blood levels should be monitored and maintained at 10-20 mcg/mL to prevent toxicity symptoms.

  4. Slurred speech
    • Rationale:

      This answer is correct because toxic side effects of phenytoin therapy include central nervous system side effects, such as slurring of speech. Additional toxic side effects include nystagmus, slurring speech, lethargy, coma, or death. Blood levels should be monitored and maintained at 10-20 mcg/mL to prevent toxicity symptoms.

  5. Hearing impairment.
    • Rationale:

      This answer is incorrect because phenytoin toxicity does not affect cranial nerve VIII. Toxic side effects do include dysarthria, where cranial nerves V, VII, IX, X and XII are involved.

Overview

Phenytoin is used to prevent and treat seizures. Central nervous system side effects are commonly associated with phenytoin toxicity.

Explanation

Phenytoin toxicity includes visual changes such as diplopia, slurred speech, staggering gait, lethargy, confusion, and nausea. There are other signs of toxicity; however, bruising and excessive alertness are not among the signs of toxicity.

Learning Outcomes

Phenytoin is an anti-epileptic or anticonvulsant medication used to prevent and treat certain types of seizures. It works by decreasing the impulse activity in the brain that can cause seizures. Phenytoin is one of a few medications with therapeutic blood levels needed to be effective and prevent toxicity side effects. Blood levels should be monitored and maintained at 10-20 mcg/mL to prevent toxicity symptoms. Toxic side effects of phenytoin therapy include CNS effects such as visual disturbances, nystagmus, slurring speech, lethargy, coma, or death.

Test Taking Tip

Remember that many medications used to treat conditions associated with the brain take 2-4 weeks to work effectively and should not be discontinued abruptly.

Video Rationale