A nurse is preparing to administer phenobarbital to a client who has status epilepticus. The nurse should be aware that phenobarbital has which of the following mechanisms of action?

- **"I should stop taking these medications if I have a rash or fever."** This statement is incorrect and indicates a need for further teaching because the client should not stop taking anticonvulsant medications abruptly, as this can cause withdrawal symptoms and increase the risk of seizures¹². The client should contact their healthcare provider if they have a rash or fever, as these could be signs of an allergic reaction or infection, but they should not stop the medication without medical advice¹².

- **"I should have my blood levels checked regularly to make sure I am taking the right dose."** This statement is correct for some anticonvulsant medications, such as phenytoin, carbamazepine, and valproate, but not for others, such as levetiracetam, lamotrigine, and gabapentin¹³. The client should ask their healthcare provider which medications require blood level monitoring and how often they need to have it done¹³.

The other statements by the client are correct and do not indicate a need for further teaching:

- **"I should avoid drinking alcohol while taking these medications."** This statement is correct because alcohol can interact with anticonvulsant medications and increase their side effects, such as drowsiness, dizziness, and impaired coordination¹². Alcohol can also lower the seizure threshold and trigger seizures in some people¹².

- **"I should take these medications at the same time every day."** This statement is correct because taking anticonvulsant medications at the same time every day helps maintain a steady level of the drug in the blood and prevent seizures¹². The client should follow the prescribed schedule and dosage of their medication and not miss or skip any doses¹².

- **"I should not drive or operate heavy machinery until I know how these medications affect me."** This statement is correct because anticonvulsant medications can cause side effects that impair the client's ability to drive or operate heavy machinery, such as blurred vision, confusion, fatigue, and poor

The nurse should monitor the client for gingival hyperplasia, which is an overgrowth of the gums that can occur as an adverse effect of phenytoin¹². Gingival hyperplasia can cause bleeding, inflammation, and infection of the gums, and may interfere with chewing and oral hygiene¹². The nurse should advise the client to brush and floss their teeth regularly, and to see a dentist for regular check-ups and cleaning¹².

Choice B is wrong because hypertension, or high blood pressure, is not a common or serious adverse effect of phenytoin¹³. Phenytoin may actually lower blood pressure in some cases, especially when given intravenously¹⁴. The nurse should monitor the client's blood pressure before and during phenytoin therapy, and report any significant changes to the prescriber¹⁴.

Choice C is wrong because diarrhea is not a common or serious adverse effect of phenytoin¹³. Phenytoin may cause constipation in some people, which can be relieved by increasing fluid and fiber intake, and using laxatives if needed¹⁵. The nurse should ask the client about their bowel habits and provide appropriate interventions as needed¹⁵.

Choice D is wrong because tachycardia, or fast heart rate, is not a common or serious adverse effect of phenytoin¹³. Phenytoin may cause bradycardia, or slow heart rate, in some cases, especially when given intravenously or in high doses¹⁴. The nurse should monitor the client's heart rate and rhythm before and during phenytoin therapy, and report any significant changes to the prescriber¹⁴.