Chapter 18 - Drugs Used for Seizure Disorders

An intravenous (IV) bolus of phenytoin (Dilantin) is administered with the patient under electrocardiographic (ECG) monitoring. Which risk factor should the nurse be prepared to assess? 1) Bradycardia 2) Myocardial infarction 3) Atrial fibrillation 4) Bundle branch block

Bradycardia Rationale: Bradycardia is a risk when phenytoin is administered intravenously. Therefore, it is administered slowly at a rate not exceeding 25 to 50 mg/min and with the patient under ECG monitoring. If bradycardia occurs, boluses are stopped until the heart rate returns to normal. A myocardial infarction, bundle branch block, and atrial fibrillation are not associated with the IV administration of phenytoin.

Which drug used in the treatment of seizures requires careful monitoring of renal function? 1) Carbamazepine (Tegretol) 2) Lamotrigine (Lamictal) 3) Valproic acid (Depakene) 4) Primidone (Mysoline)

Carbamazepine (Tegretol) Rationale: Carbamazepine is nephrotoxic; a patient's renal function should be monitored while taking this drug. Lamotrigine causes rash, primidone can cause blood dyscrasias, and valproic acid can cause blood dyscrasias and hepatotoxicity, but none of these affect renal function.

What does the nurse monitor in a patient taking zonisamide (Zonegran)? 1) Blood pressure 2) Cardiac dysrhythmias 3) Complete blood count (CBC) 4) Deep tendon reflexes

Complete blood count (CBC) Rationale: Zonisamide may cause blood dyscrasias. Routine monitoring of CBC with differential is important. The patient should also be monitored for sore throat, fever, purpura, jaundice, or excessive weakness. Zonisamide does not have an effect on blood pressure, deep tendon reflexes, or cardiac functioning.

Which measurement is the best indicator of how well an antiseizure medication is working? 1) Serum drug levels 2) Liver enzymes 3) Frequency and duration of seizures 4) Urinary output

Frequency and duration of seizures Rationale: The frequency and duration of seizures is the best indicator of how well a medication is working. All patients with a seizure disorder should keep a diary of seizure activity. Blood level measurements of medications indicate if the medication is within a therapeutic range, but the patient may still continue to have seizures. Although measuring liver enzymes is important with several antiseizure medications, it does not indicate how well the medication is controlling seizure activity. Measuring urinary output does not indicate how well a medication is controlling seizure activity.

A patient with diabetes is started on phenytoin (Dilantin) for partial seizures. What does the nurse closely monitor in this individual? 1) Weight loss 2) Hypoglycemia 3) Blood pressure 4) Hyperglycemia

Hyperglycemia Rationale: The patient should be monitored for hyperglycemia because phenytoin has the potential to elevate blood glucose levels, particularly during the early weeks of therapy. Phenytoin does not have an effect on blood pressure. Phenytoin has not been shown to decrease blood glucose levels or cause weight loss in patients with diabetes.

A patient taking phenytoin (Dilantin) has started attending college and reports frequently drinking alcohol with friends. What does the nurse monitor for in this patient? 1) Hyperglycemia 2) Increased seizure activity 3) Hypertension 4) Clinical manifestations of phenytoin toxicity

Increased seizure activity Rationale: The chronic use of alcohol and phenytoin will decrease blood levels of phenytoin and increase the potential for seizure activity. The combination of phenytoin and alcohol does not cause phenytoin toxicity, affect blood glucose levels, or increase blood pressure.

Which factor should be considered during data collection when evaluating the effectiveness of succinimides? 1) Presence or absence of muscle spasms 2) Patient's sleep pattern 3) Occurrence of petit mal seizures 4) Large bowel function

Occurrence of petit mal seizures Rationale: Succinimides are used for the control of absence (petit mal) seizures. Therefore, when evaluating the effectiveness of the therapy, it is essential to gather information about the occurrence of these seizures. Succinimides can cause drowsiness but do not affect sleep patterns. Succinimides do not affect muscle function or large bowel function.

Which patient should not be prescribed carbamazepine (Tegretol)? 1) Patient with new onset of seizures 2) Patient with diabetes mellitus 3) Patient with chronic hepatitis B 4) Patient with an ulcer

Patient with chronic hepatitis B Rationale: Carbamazepine may cause hepatotoxicity and should not be given to patients with preexisting liver disease. Patients with new onset of seizures or ulcers should have no problems with taking carbamazepine. Carbamazepine has not been shown to cause increased blood glucose levels in individuals with diabetes.

A patient taking phenytoin (Dilantin) and isoniazid reports feeling lethargic. Nystagmus is noted on physical examination. Which problem does this information suggest to the nurse? 1) Phenytoin toxicity 2) Abrupt discontinuation of isoniazid 3) Tubercular reactivation 4) Liver damage

Phenytoin toxicity Rationale: Phenytoin toxicity is characterized by nystagmus, sedation, or lethargy and is enhanced by isoniazid. Thus, the report of lethargy and the finding of nystagmus in conjunction with the use of both phenytoin and isoniazid suggest phenytoin toxicity. The clinical manifestations noted in this patient are not consistent with tubular reactivation, symptoms experienced with abrupt discontinuation of isoniazid, or liver damage.

Which antiepileptic drug is effective for almost all forms of seizures? 1) Phenobarbital (Luminal) 2) Carbamazepine (Tegretol) 3) Phenytoin (Dilantin) 4) Valproic acid (Depakene)

Valproic acid (Depakene) Rationale: Valproic acid may be used as single-drug therapy for treating patients with a combination of generalized tonic clonic, absence, or myoclonic seizures. Carbamazepine may be used to control generalized tonic clonic and partial seizures; it is not effective with myoclonic or absence seizures. Phenobarbital is most effective in treating partial and generalized tonic clonic seizures and generalized myoclonic seizures. Phenytoin is used most often to control partial onset seizures and generalized tonic clonic seizures.

A patient has been started on lamotrigine (Lamictal). How does the nurse instruct this patient to take the medication to decrease the incidence of gastric irritation? 1) One hour before meals or 2 hours after meals 2) At bedtime 3) Between meals with a glass of orange juice 4) With milk or food

With milk or food Rationale: Lamotrigine may cause gastric irritation; taking it with milk or food will decrease the potential for gastric upset. Lamotrigine may cause gastric irritation; taking it with orange juice will not decrease the incidence of this. Taking lamotrigine at bedtime or between meals will not decrease the incidence of gastric irritation.