Chapter 23: Anti-seizure Agents

The nurse has been educating the client on the self-administration of phenytoin. Which statement made by the client demonstrates an understanding of the medication?

"I'll make sure to take the drug with food." Explanation: Phenytoin should be taken with food to reduce the chance of stomach upset. It should be taken on a regular basis and not only when a seizure occurs. The client should not arbitrarily reduce the dose of phenytoin. Abrupt cessation can cause seizures.

A client has been diagnosed with partial seizures and has been prescribed carbamazepine. When providing health education about the safe and effective use of this medication, what should the nurse teach the client?

"It's safest if you avoid drinking alcohol while you're taking this drug." Explanation: Use of alcohol during treatment with carbamazepine is contraindicated due to the potential for CNS depression. Carbamazepine is taken on an ongoing basis to prevent partial seizures; it is not a treatment for impending seizure activity. It is administered orally, not by injection, and it does not necessitate significant dietary changes.

During an in-service, the charge nurse explains to the licensed vocational nurse (LVN) that there are six categories of anticonvulsants with different mechanisms of action. The LVN demonstrates understanding of the action of the miscellaneous drug, gabapentin, by stating which of the following?

"This drug is a gamma-aminobutyric acid (GABA) agonist." Explanation: Gabapentin is a miscellaneous drug acting as a GABA agonist. Hydantoins stabilize the hyperexcitability postsynaptically in the motor cortex of the brain. Succinimides depress the motor cortex, thus raising the seizure threshold. Benzodiazepines elevate the seizure threshold by decreasing postsynaptic excitation.

One week ago, a client began taking ethosuximide 500 mg/day PO for the treatment of absence seizures. The client reports gastrointestinal (GI) upset after taking with the drug. What health education should the nurse provide?

"Try taking your pills at the same time as you eat some food." Explanation: If GI irritation occurs with ethosuximide or other anticonvulsants, the client should be encouraged to take the medication with food to reduce this adverse effect. Taking the drug 1 to 2 hours after meals would not reduce this effect. The nurse must be cautious when recommending the use of OTC medications. GI effects are unlikely to necessitate a change in medications.

The nurse is providing client teaching with a client who is newly diagnosed with epilepsy. The client asks, "Can I still drive to work?" What is the nurse's best response?

"You likely won't be able to until your seizures are controlled by medication" Explanation: Clients newly diagnosed with epilepsy will not be able to drive. However, after the client's seizures are controlled (usually for 6 months to 2 years depending on state law), the client may be able to regain the ability to drive. This does not, however, mean that the client has to use public transportation. Serum drug levels are not the determining criterion.

A nurse should monitor a client closely for increased CNS depressant effects when an anticonvulsant is used concomitantly with which substances? (Select all that apply.) -Analgesics -Oral contraceptives -Alcohol -Antibiotics -Antidiabetic medications

-Analgesics -Alcohol Explanation: The concomitant use of anticonvulsants and analgesics or alcohol can result in increased CNS depressant effects.

The nurse is monitoring the serum carbamazepine level of a client. Which result would lead the nurse to notify the prescriber that the client most likely needs an increased dosage?

2 mcg/mL Explanation: Therapeutic serum carbamazepine levels range from 4 to 12 mcg/mL. Therefore, a level under 4 mcg/mL would suggest that the drug has not reached therapeutic levels, so the dosage may need to be increased.

A client is receiving phenytoin. The nurse monitors the client's plasma drug level. Which level would alert the nurse to the possibility of toxicity?

27 µg/mL Explanation: Phenytoin plasma levels between 10 and 20 µg/mL give optimal anticonvulsant effect. However, many clients achieve seizure control at lower serum concentration levels. Levels greater than 20 µg/mL are associated with toxicity.

The nurse has just begun administering phenobarbital intravenously to a child within status epilepticus. The nurse would expect this drug to begin working within which time frame?

5 minutes Explanation: IV phenobarbital has an onset of action of approximately 5 minutes.

The neurological nurse cares for several clients who have seizure disorders. Which client should the nurse monitor most closely for indications of drug dependence?

A client with a history of tonic-clonic seizures who takes phenobarbital Explanation: Barbiturates, such as phenobarbital, have an associated risk for dependence. This is not true of the other listed drugs.

A client has been admitted to the emergency department and is experiencing tonic-clonic seizures. What intervention should the nurse prioritize?

Administration of phenytoin IV as prescribed Explanation: Active seizure activity is an emergency and the client's immediate physiological needs supersede the importance of therapeutic relationship. Phenytoin IV is among the most common treatments for tonic-clonic seizures; gabapentin PO is not typically used for this purpose, and PO administration of any type is unsafe due to the risk for aspiration. Treatment would not be withheld pending assessment of renal and hepatic function.

An 18-year-old client has been taking phenytoin for the past 6 months for epileptic seizures. The client's phenytoin levels routinely fall within the therapeutic range. The client contacts the health care provider reporting nausea, headache, and diarrhea. What would be the most appropriate intervention based on the assessment of the client's symptoms and laboratory results?

Advise the client to have his blood redrawn today to ensure that it is not at a toxic level. Explanation: Clients may demonstrate adverse effects even if the serum level of phenytoin is "normal"; it is important to adjust the dose to the clinical response of the client, not the serum level.

A nurse is caring for a patient who is going to take ethosuximide. During the nurse's initial assessment, the nurse learns that the patient's history includes hepatitis. Which laboratory test should be done before therapy is started?

Alanine aminotransferase (ALT) Explanation: Because an adverse effect of ethosuximide can be liver function impairment, a baseline liver function study that includes the ALT should be done prior to starting ethosuximide. Baseline values will help the nurse determine if the drug is causing the abnormal values, and liver function studies will need to continue throughout the therapy. Blood glucose level would determine the glucose level in the blood. BUN would help determine urinary function. PTT is a test to assess the intrinsic system, which is the common pathway of clot formation in the blood. While these tests are important, they do not have a direct relationship to ethosuximide use.

The school nurse sees a child who has had an absence seizure. Which characteristics are typical of this type of seizure?

Alterations in consciousness that last seconds Explanation: Absence seizures are characterized by abrupt alterations in consciousness that last only a few seconds.

A client is receiving carbamazepine therapy and the client's latest serum level of the drug is 13 mcg/mL. What action is most appropriate?

Anticipate a reduction in dosage Explanation: A serum carbamazepine level of 13 mcg/mL is slightly over the therapeutic range of 4 to 12 mcg/mL, indicating need for a reduction in dosage. This not an emergency, though it needs to be addressed. This result does not threaten the client's renal function.

A nurse is treating a patient who is receiving carbamazepine for a seizure disorder. The nurse knows that carbamazepine is contraindicated in patients with which diseases or disorders?

Bone marrow depression Explanation: Carbamazepine is contraindicated in patients with previous bone marrow depression.

A patient with cortical focal seizures has been prescribed phenobarbital. What adverse reaction should the nurse monitor for in the patient?

CNS depression Explanation: The nurse should monitor CNS depression in the patient undergoing phenobarbital treatment. Gingival hyperplasia is an adverse reaction in a patient administered ethotoins. Ataxia and urticaria are adverse reactions in patients undergoing anticonvulsant ethosuximide therapy.

A client is diagnosed with trigeminal neuralgia. What antiepileptic agent may be used to treat this disorder?

Carbamazepine Explanation: Carbamazepine is prescribed to treat trigeminal neuralgia. Neither phenytoin, fosphenytoin, nor ethosuximide is administered for trigeminal neuralgia.

A client is prescribed lamotrigine for control of partial seizures. What is the most important medication teaching information the nurse should emphasize from the plan of care?

Contact the health care provider immediately if rash appears. Explanation: GI upset, headache, rash, and dizziness are all adverse reactions of lamotrigine. The most important teaching point to emphasize is to notify the health care provider if a rash appears. A rash can develop into a Stevens-Johnson syndrome rash, a severe and potentially fatal rash.

The nurse is caring for a 15-year-old male who was involved in a motor vehicle accident and, as a result, sustained a closed head injury. The health care provider ordered phenytoin prophylactically to prevent seizures. The nurse understands that phenytoin works by what mechanism?

Decreases the sodium influx into the cell, thereby preventing the cell from producing a stimulus Explanation: Phenytoin (Dilantin) is the prototype drug that controls seizures by decreasing sodium influx into the cells. Sodium influx produces an action potential, which then causes the neurons to fire.

When describing the action of barbiturates and barbiturate-like agents in the control of seizures, what would the nurse include?

Depression of motor nerve output Explanation: The barbiturates and barbiturate-like drugs depress motor nerve output, inhibit impulse conduction in the ascending reticular activating system (RAS), depress the cerebral cortex, and alter cerebellar function. They stabilize nerve membranes throughout the CNS directly by influencing ionic channels in the cell membrane, thereby decreasing excitability and hyperexcitability to stimulation.

For a client with a known heart block (conduction disorder), what medication is contraindicated?

Dilantin Explanation: Phenytoin, carbamazepine, ethosuximide, lamotrigine, topiramate, and zonisamide are contraindicated or must be used cautiously in clients with hepatic or renal impairment. Additional contraindications include phenytoin in clients with sinus bradycardia or heart block; carbamazepine in those with bone marrow depression (e.g., leukopenia, agranulocytosis); and tiagabine and valproic acid in people with liver disease.

When combination therapy is ineffective, what needs to be reassessed?

Drug-drug interactions Explanation: Many of the AEDs have drug-drug interactions. Therefore, it is important to monitor for drug-drug interactions to arrange to adjust dosages appropriately if any drug is added or withdrawn from the drug regimen. The age and gender of the patient would not need to be reassessed and neither would whether or not the patient is truly having seizures.

A client has been prescribed carbamazepine for the prevention of seizures. What action should the nurse perform?

Educate the client about the need to take the pills as scheduled Explanation: Carbamazepine is administered orally on an ongoing basis. It is not an emergency treatment for seizure activity.

The community health nurse also assists the health care provider in the decision-making process for AED drug titration by performing which function?

Ensuring that the client makes the appointments for serum drug levels Explanation: The community health nurse may assist the provider to titrate drug doses by ensuring that the client keeps appointments for serum drug level testing and follow-up care.

The nurse instructs the parent of a young school-age child with a seizure disorder who takes an AED to be alert for what signs and symptoms?

Excessive sedation and interference with learning and social development Explanation: AEDs must be used cautiously to avoid excessive sedation and interference with learning and social development.

The nurse is caring for an 84-year-old client who is taking an AED and recognizes that this client is at increased risk for which condition?

Falls Explanation: In older adults, decreased elimination by the liver and kidneys may lead to drug accumulation, with subsequent risks of dizziness, impaired coordination, and injuries due to falls.

When reviewing a journal article about seizure disorders, the nurse would expect to find tonic-clonic seizures and myoclonic seizures being classified as which type of seizures?

Generalized seizures Explanation: Tonic-clonic seizures and myoclonic seizures are classified as generalized seizures. Partial seizures can be simple or complex. Complex seizures are partial seizures that involve impaired consciousness and variable unconscious repetitive actions, staring gaze, and hallucinations/delusions. Atonic seizures are a type of generalized seizure involving the loss of muscle tone where the person suddenly drops.

A client is receiving a hydantoin as treatment for tonic-clonic seizures. The nurse includes a discussion of what when teaching the client about this drug?

Gingival hyperplasia Explanation: Hydantoins may cause gingival hyperplasia, severe liver toxicity, and bone marrow suppression. Physical dependence and withdrawal syndrome are associated with benzodiazepines.

An older adult client has been prescribed an antiseizure medication and is experiencing central nervous system depression. What is the nurse's most appropriate action?

Implement falls precautions Explanation: CNS depression creates a risk for falls, especially in older clients. There is no need to assess vital signs on an hourly basis and the harm of bed rest exceeds the benefits. Occupational therapy has no direct relationship with treating CNS depression.

The nurse is formulating a care plan for a client with a seizure disorder. Which intervention would be an appropriate for the nurse to include?

Informing the client and family that seizure control is not gained immediately Explanation: The nurse should inform the client and family that seizure control is not gained immediately when drug therapy is started. The goal is to avoid unrealistic expectations and excessive frustration while drugs and dosages are being changed in an effort to determine the best regimen for the client.

A client has been prescribed valproic acid for the treatment of myoclonic seizures. When reviewing this client's latest laboratory results for signs of adverse effects, what results should the nurse prioritize?

Liver enzymes Explanation: Valproic acid is associated with liver toxicity, more so than leukopenia, renal damage or electrolyte disturbances.

What should the nurse include as a possible adverse effect when teaching a client about phenytoin?

Liver toxicity Explanation: Liver toxicity is a potential adverse effect of phenytoin. Constipation, not diarrhea, is an adverse effect of phenytoin. Bone marrow suppression and leukopenia would be adverse effects of phenytoin. Physical dependence is an adverse effect associated with the use of benzodiazepines and barbiturates.

A client is to receive ethotoin. The nurse would expect to administer this drug by which route?

Oral Explanation: Ethotoin is administered orally.

A client is prescribed methsuximide. The nurse should expect to administer this drug by which route?

Oral Explanation: Methsuximide is administered orally. Diazepam can be administered rectally. Diazepam or phenobarbital may be administered intramuscularly. Diazepam, fosphenytoin, phenytoin, valproic acid, and phenobarbital can be administered intravenously.

A nurse is preparing to administer an anticonvulsant that produces its effects by stabilizing the hyperexcitability postsynaptically in the motor cortex of the brain. Which medication would the nurse administer?

Phenytoin Explanation: Hydantoins like phenytoin elicit their effects by stabilizing the hyperexcitability postsynaptically in the motor cortex of the brain. Valproic acid increases the levels of GABA to help stabilize the membranes. Ethosuximide depresses the motor cortex, creating a higher threshold before the nerves react to the convulsive stimulus. Lorazepam elevates the seizure threshold by decreasing postsynaptic excitation.

The nurse is reviewing the medical record of a client with partial seizures who is prescribed drug therapy. The nurse would question the order for what if the nurse finds that the client has a history of alcohol abuse?

Pregabalin Explanation: Pregabalin has a controlled substance rating of category V because it causes feelings of well-being and euphoria. Subsequently, its use should be limited in clients who have a history of abuse of medications and alcohol. Increased CNS depression would occur if the client ingested alcohol with either topiramate, felbamate, or tiagabine.

A 15-year-old is observed having a tonic-clonic seizure at school. Which behavior would allow the school nurse to recognize the clonic phase of the seizure?

Rapid rhythmic and symmetric jerking movements Explanation: The tonic phase of a tonic-clonic seizure involves sustained contraction of skeletal muscles, abnormal postures, and absence of respiration. The clonic phase of the seizure is characterized by rapid rhythmic and symmetric jerking movements of the body.

Which nursing diagnosis would be most important for a nurse to include in the plan of care for a client who is receiving an antiseizure agent and experiencing common adverse effects?

Risk for injury Explanation: CNS depression that accompanies many antiseizure agents could lead to injury. Therefore risk for injury and safety measures would be the priorities. Imbalanced fluid volume would be appropriate if the client was experiencing vomiting or diarrhea or showing signs of dehydration. Impaired skin integrity might be appropriate if the client developed a rash. Ineffective coping would be appropriate if the client was verbalizing difficulties with his condition or therapy.

The nurse is participating in the care of a client in status epilepticus who is receiving phenobarbital IV. Which nursing diagnosis should the nurse prioritize during this client's current care?

Risk for injury related to seizure activity Explanation: Seizures present an acute risk for injury which the nurse must prioritize when caring for the client. Cognitive and/or sensory disruptions are likely as well, but none of these presents such a high risk to the client's safety as the risk for injury.

A patient is prescribed daily doses of phenytoin for seizures. The nurse knows that a single dose should not be missed during the course of treatment. Which condition could result if a dose is missed?

Status epilepticus Explanation: Status epilepticus may result from abrupt discontinuation of the drug, even when the anticonvulsant is being administered in small daily doses. Abrupt discontinuation of the drug does not cause CNS depression, hypotension, or nystagmus. CNS depression, hypotension, and nystagmus are adverse reactions of phenytoin.

A client is prescribed topiramate. The nurse cautions the client to avoid the intake of alcohol for which reason?

The client is at risk for increased CNS depression. Explanation: Combining alcohol with topiramate increases the client's risk for CNS depression. Topiramate combined with alcohol does not result in a disulfiram-like reaction. Drug dependency is not associated with the use of topiramate and alcohol. The combination of topiramate and alcohol is not associated with the development of a hypertensive crisis.

A client, newly diagnosed with a seizure disorder, asks the nurse why the client is receiving a specific drug. What would be the best answer by the nurse?

When prescribing an AED, the health care provider takes into account the type of seizure the client is having. Explanation: Type of seizure is a major factor in drug selection. Age and gender are not factors that impact the choice of AED.

In a person being treated for a diagnosed seizure disorder, what is the most common cause of status epilepticus?

abruptly stopping the antiseizure medications Explanation: In a person taking medications for a diagnosed seizure disorder, the most common cause of status epilepticus is abruptly stopping AEDs. In other clients, regardless of whether they have a diagnosed seizure disorder, causes of status epilepticus include brain trauma or tumors, systemic or central nervous system (CNS) infections, alcohol withdrawal, and overdoses of drugs (e.g., cocaine, theophylline).

What is a common risk for epileptic seizures during late infancy to early childhood?

fever Explanation: Epilepsy can be classified as idiopathic or attributable to a secondary cause. Secondary causes in infancy include developmental defects, metabolic disease, or birth injury. Fever is a common cause during late infancy and early childhood, and inherited forms usually begin in childhood or adolescence. Learning disability, medication overdose, and malnutrition are not risk factors.

What is the primary medication prescribed to relieve pain associated with shingles?

gabapentin Explanation: Gabapentin is the first oral medication approved by the FDA for the management of postherpetic neuralgia. Meperidine and morphine sulfate will provide pain relief, but neither are effective in postherpetic neuralgia relief. Naproxen sodium will decrease inflammation but is not effective for postherpetic neuralgia relief.

What is the most common drug of choice prescribed for the treatment of seizure activity in adults?

phenytoin Explanation: The oldest and most widely used antiepileptic drug (AED), phenytoin is often the initial drug of choice, especially in adults. None of the remaining drugs are as widely prescribed.

A nurse is caring for a client with trigeminal neuralgia at a health care facility. The health care provider has prescribed carbamazepine. In which case is the use of carbamazepine contraindicated in clients with:

renal impairment. Explanation: The nurse should know that carbamazepine is contraindicated among clients with renal impairment. Carbamazepine is not contraindicated in those with nervous breakdown, hearing impairment, and respiratory depression.

The nurse is providing education to an adult client who has been prescribed lamotrigine for a seizure disorder. The nurse should inform the client that the medication must be stopped if what unexpected reaction develops?

skin rash Explanation: The FDA has issued a black box warning related to the potential development of serious dermatologic reactions. It should be discontinued at the first sign of skin rash in an adult. Insomnia, anorexia, and fever aren't known adverse effects, so the nurse wouldn't mention them in the teaching.

What type of seizure activity is characterized by generalized tonic-clonic convulsions lasting for several minutes during which the client does not regain consciousness?

status epilepticus Explanation: Status epilepticus is a life-threatening emergency characterized by generalized tonic-clonic convulsions lasting for several minutes or occurring at close intervals during which the client does not regain consciousness. None of the other options present with this described experience.