Chapter 23: Anti-seizure Agents PREPU

A female client's seizure disorder has been successfully controlled by AEDs for years. She and her husband decide that it is time to start a family. She asks the nurse if it is safe for the fetus for her to continue her AEDs as prescribed. What is the nurse's best response?

"They are considered teratogenic." Sexually active adolescent girls and women of childbearing potential who require an AED must be evaluated and monitored very closely, because all of the AEDs are considered teratogenic. In general, infants exposed to one AED have a significantly higher risk of birth defects than those who are not exposed, and infants exposed to two or more AEDs have a significantly higher risk than those exposed to one AED.

A client who is receiving phenytoin has a serum drug level drawn. Which result would the nurse interpret as within the therapeutic range?

12 mcg/mL The therapeutic serum phenytoin levels range from 10 to 20 mcg/mL. Thus, a level of 12 mcg/mL would fall within this range.

A patient is receiving carbamazepine therapy. Which serum drug level result would lead the nurse to suspect that the patient needs a decrease in dosage?

14 mcg/mL A serum carbamazepine level of 14 mcg/mL is over the therapeutic range of 4 to 12 mcg/mL, necessitating a reduction in dosage. A serum carbamazepine level of 6 mcg/mL is within the therapeutic range of 4 to 12 mcg/mL. No dosage reduction would be necessary. A serum carbamazepine level of 8 mcg/mL is within the therapeutic range of 4 to 12 mcg/mL. No dosage reduction would be necessary. A serum carbamazepine level of 12 mcg/mL is within the therapeutic range of 4 to 12 mcg/mL. No dosage reduction would be necessary.

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 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.

When reviewing the results of a patient's serum phenytoin level, which level would indicate toxicity?

22 mcg/mL A serum phenytoin level of 22 mcg/mL is outside the therapeutic range of 10 to 20 mcg/mL and would be considered toxic. A serum phenytoin level of 10 mcg/mL is within the therapeutic range of 10 to 20 mcg/mL. A serum phenytoin level of 14 mcg/mL is within the therapeutic range of 10 to 20 mcg/mL. A serum phenytoin level of 18 mcg/mL is within the therapeutic range of 10 to 20 mcg/mL.

A child is experiencing febrile seizures for which phenobarbital is ordered to be given intravenously. The dose is administered at 10 AM. The nurse understands that a second dose of the drug may be given at which time?

4 PM When phenobarbital is given to a child intravenously for treatment of a febrile seizure, a second dose may be repeated in 6 hours, which in this situation would be 4 PM.

In a person taking medications for a diagnosed seizure disorder, the most common cause of status epilepticus is:

Abruptly stopping the antiseizure medications. 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 (eg, cocaine, theophylline).

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

A patient who has been taking valproic acid (sodium valproate) for a seizure disorder is asking the nurse about getting pregnant. Why is pregnancy discouraged in women who are being treated for seizure disorders?

Antiepilepsy drugs are teratogenic Antiepileptic drugs must be used cautiously during pregnancy because they are teratogenic in animals. Seizure disorders are not genetic. Seizure disorders are not familial. Antiepilepsy medications do not decrease fertility.

What would a nurse identify as a local anesthetic agent?

Benzocaine Benzocaine is a local ester anesthetic. Thiopental is a barbiturate general anesthetic. Enflurane is a volatile liquid general anesthetic. Propofol is a nonbarbiturate general anesthetic.

A patient admitted to a health care facility for appendicitis surgery is administered methohexital as a general anesthesia. Which condition should the nurse observe in the patient as the effect of the administration of methohexital?

CNS depression The nurse is most likely to observe CNS depression. Methohexital is an ultrashort-acting barbiturate that depresses the CNS to produce hypnosis and anesthesia, but it does not produce analgesia. Skeletal muscle relaxation is caused by skeletal muscle relaxants, halothane and enflurane. An anesthetic state characterized by profound analgesia is produced by ketamine, which is a rapid-acting general anesthetic. Neuroleptanalgesia is caused by a combination of fentanyl and droperidol.

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

CNS depression 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.

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 physician 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 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 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.

Which factor should the clinician reassess when combination therapy is ineffective?

Drug-drug interactions If combination therapy is ineffective, the clinician may need to reassess the patient for type of seizure, medical conditions or drug-drug interactions that aggravate the seizure disorder or decrease the effectiveness of antiseizure drugs, and compliance with the prescribed drug therapy regimen.

A patient is experiencing absence seizures. Which agent would the nurse most likely expect the physician to order as the drug of choice?

Ethosuximide Ethosuximide is considered the drug of choice for treating absence seizures. Valproic acid is considered the second choice drug for treating absence seizures. Clonazepam may be used to treat absence seizures, but it is not the drug of choice. Diazepam is used to treat clonic-tonic seizures and status epilepticus.

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

Which type of seizures involves a loss of consciousness?

Generalized seizures Generalized seizures involve a loss of consciousness.

Tonic-clonic seizures and myoclonic seizures are classified as what type of seizures?

Generalized seizures Tonic-clonic seizures and myoclonic seizures are classified generalized seizures.

Which intervention would be an appropriate part of a plan of care for a patient with a seizure disorder?

Informing the patient and family that seizure control is not gained immediately The nurse should inform the patient 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 patient.

What best reflects the action of barbiturates when used to control seizures?

Inhibition of impulse conduction Barbiturates inhibit impulse conduction in the ascending reticular activating system. Barbiturates depress the cerebral cortex, depress cerebellar functioning, and depress motor nerve output.

A nurse is caring for a 68-year-old woman who has just returned to her room after a gastroscopy. Prior to beginning the procedure, lidocaine was given to numb her throat. Which of the following is the priority nursing intervention?

Instruct the patient and family that she should not eat or drink for at least 1 hour. The nurse must ensure that the patient does not eat or drink anything for at least 1 hour following administration of viscous lidocaine to the throat. Because of the numbing effects of viscous lidocaine, the patient will experience impaired swallowing and is at risk for aspiration. Viscous lidocaine should not affect the patient's blood pressure or heart rate. The nurse will need to provide assistance to the patient when she gets out of bed to ambulate, but this is due to the effects of the anesthesia, not the lidocaine.

The following are nonbarbiturate general anesthetics. Place in the proper sequence based on their onset of action from fastest to slowest.

Ketamine Propofol Etomidate Droperidol Ketamine has an onset of action within 30 seconds. Propofol has an onset of action within 30 to 60 seconds. Etomidate has an onset of action within 60 seconds. Droperidol has an onset of action within 3 minutes.

What would the nurse include as possible adverse effects when teaching a patient about phenytoin?

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

Which is the drug of choice in the treatment of status epilepticus, an emergency characterized continual seizure activity with no interruptions?

Lorazepam (Ativan) Lorazepam (Ativan) is the drug of choice in the treatment of status epilepticus, an emergency characterized continual seizure activity with no interruptions.

Which anticonvulsant elicits its effects by depressing the motor cortex and creating a higher threshold before nerves react to the convulsive stimuli?

Methsuximide (Celontin) Succinimides like methsuximide (Celontin) elicits their effects by depressing the motor cortex and creating a higher threshold before nerves react to the convulsive stimuli.

A client received fentanyl during a surgical procedure. The nurse will have what drug available to treat any possible respiratory depression associated with the use of fentanyl?

Naloxone Fentanyl is an opioid analgesic, and the nurse will have naloxone on hand to reverse the effects of the opioid that is causing respiratory depression.

A nurse is caring for a patient prescribed phenobarbital for status epilepticus. What intervention should the nurse perform when the patient has been administered the drug?

Observe respirations frequently. When caring for a patient who has been administered phenobarbital, the nurse should observe respirations frequently. The nurse need not monitor blood glucose levels or body temperature. The nurse need not record fluid input and output. The nurse may need to observe blood glucose levels if the patient is being administered antidiabetic medications along with an anticonvulsant.

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

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

Oral Ethotoin is administered orally.

A nurse is caring for a patient with trigeminal neuralgia at a health care facility. The physician has prescribed carbamazepine. In which case is the use of carbamazepine contraindicated?

Patients with renal impairment The nurse should know that carbamazepine is contraindicated among patients with renal impairment. The carbamazepine drug is not contraindicated in patients with nervous breakdown, hearing impairment, and respiratory depression.

After teaching a male patient who is receiving lamotrigine about possible adverse effects, the nurse determines that the patient has understood the teaching when the patient states that he will notify his health care provider immediately if he develops:

Rash Lamotrigine has been associated with very serious to life-threatening rashes and the drug should be discontinued at the first sign of any rash. Anorexia is a common adverse GI effect. Fatigue is a common adverse CNS effect. Upper respiratory infection is an adverse effect of the drug, but it is not life threatening and does not need to be reported immediately.

A client is receiving lamotrigine as treatment for partial seizures. Which assessment finding would lead the nurse to stop the drug immediately?

Rash Lamotrigine has been associated with very serious to life-threatening rashes, and the drug should be discontinued at the first sign of any rash. Somnolence and confusion are typical CNS effects; anorexia is a common gastrointestinal effect.

While taking the vital signs of a hospitalized client admitted for seizure control due to epilepsy, the nurse notices a bloody toothbrush on the client's bedside table and scattered bruising over the client's extremities. What is the nurse's best action?

Report the findings to the primary health care provider immediately. The client has a history of epilepsy and is likely taking anticonvulsants. Hematologic changes when taking anticonvulsants needs to be reported immediately to the health care provider. Such changes include bleeding gums and easy bruising. Abuse is not the likely cause of the client's bruising given the history of epilepsy. Telling the client to ask for assistance when ambulating and offering a soft toothbrush are appropriate, but the health care provider needs to be notified immediately about the hematologic changes.

The nurse is preparing to admit a client who has received conscious sedation. What is the most important vital sign to assess when the client returns from the procedure?

Respirations Conscious sedation may be used when the client is receiving local anesthetic, but a sedative (opioid or antianxiety medication) is also added for client comfort or if the client may need to lie still for a long period of time. These sedating drugs may cause respiratory depression, so it is most important to assess the respiratory rate.

A 77-year-old man with a long history of absence seizures has been treated with ethosuximide for many years. The man is now in the process of moving to a long-term care facility and a nurse is creating a plan of care. The nurse understands the potential adverse effects of this drug and would consequently prioritize which nursing diagnoses?

Risk for Falls Common adverse effects of ethosuximide are drowsiness, dizziness, and lethargy. Respiration, urinary function, and skin integrity are not normally affected by the use of ethosuximide.

A nurse is caring for a patient administered ethotoin. What are signs of toxicity for which the nurse should monitor the patient?

Slurred speech The nurse should monitor the patient for slurred speech which is a sign of toxicity. Constipation, diarrhea, and urinary frequency are not signs of toxicity of ethotoin. Constipation and diarrhea are adverse reactions of barbiturates. Urinary frequency is an adverse reaction of succinimides.

The nurse is caring for a woman who is about to deliver her infant by Caesarean section and prepares the client for what type of anesthesia?

Spinal Spinal anesthesia is a type of regional anesthesia that provides a loss of feeling and movement in the lower extremities, lower abdomen and perineum. In a Caesarean section, the infant is delivered through an incision in the lower abdomen. Topical and local infiltration would not provide adequate pain relief. General anesthesia is not commonly used for a Caesarean section because the infant would also receive effects from the anesthesia. It may be used if the Caesarean must be performed in an emergency.

The nurse is planning patient education for a patient on antiseizure medications. The nurse should inform the patient that abrupt withdrawal from the medications can precipitate which problem?

Status epilepticus In patients receiving drug treatment for seizure disorders, the most common cause of status epilepticus is abruptly stopping antiseizure drugs.

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 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 29-year-old female patient in labor has just received epidural anesthesia. Before the procedure her blood pressure was 120/78 and her pulse was 60 bpm. Now her blood pressure is 100/60 and her pulse is 80 bpm. She reports a metallic taste in her mouth, hears a ringing in her ears, and appears confused. What is this patient most likely experiencing?

Systemic toxicity from local anesthesia CNS (central nervous system) symptoms (such as tinnitus and disorientation) are commonly present before hemodynamic changes are evidenced when a patient has systemic toxicity. Systemic toxicity in this case is from a local anesthetic being injected into a blood vessel.

A patient with partial seizures has been prescribed succinimides at a health care facility. The patient experiences GI upset after succinimides administration. What should the nurse instruct the patient to do?

Take the drug with food or milk. If the patient experiences GI upset after succinimides administration, the nurse should instruct the patient to take the drug with food or milk. The nurse need not instruct the patient to take the drug once only at bedtime, before meals, nor avoid taking fruit juice.

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

The patient is at risk for increased CNS depression. Combining alcohol with topiramate increases the patient'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 hypterensive crisis.

A female client reports that her seizure was preceded by a brief warning, which she describes as an unusual smell. This is known as a(n):

aura. Tonic-clonic seizures are sometimes preceded by an aura—a brief warning, such as a flash of light or a specific sound or smell.

A patient has a history of tonic-clonic seizures that have been successfully treated with phenytoin (Dilantin) for several years. Phenytoin achieves a therapeutic effect by:

decreasing the influx of sodium into neurons. Phenytoin reversibly binds to sodium channels while they are in the inactive state. This binding delays the return of the channel to an active state. Because sodium can enter the cell to initiate an action potential only when the channels are active, the time between action potentials is greatly lengthened, the neurons cannot fire at an excessive rate, and excessive muscle contractions that occur in grand mal-type seizures are prevented. Phenytoin does not directly affect the function of calcium channels or levels of GABA and glutamate.

A common cause of seizures for a client in late infancy to early childhood is:

fever. 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.

The nurse is caring for a 26-year-old woman with partial seizures. The nurse has been prescribed oxcarbazepine (Trileptal) as monotherapy. It will be critical for the nurse to inform the patient that:

since she is taking oral contraceptives, she will need to use an additional form of birth control. Oxcarbazepine causes the circulating levels of oral contraceptives to decrease by up to half. The nurse should teach the patient that she will need to use an additional form of birth control. Fatigue may be a concern, and the patient should allow for rest periods during the day. Diplopia and abnormal vision can be adverse effects of the drug and eye exams should be part of the patient's treatment regimen but they are not needed every other month. Informing the patient that GI problems are common adverse effects is important but not as critical as preventing an unplanned pregnancy.

The seizure type that is characterized by generalized tonic-clonic convulsions lasting for several minutes during which the client does not regain consciousness is known as:

status epilepticus. 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. Hypotension, hypoxia, and cardiac dysrhythmias may also occur. There is a high risk of permanent brain damage and death unless prompt, appropriate treatment is instituted.

Prior to surgery, the nurse will review the client's chart and ensure that the surgeon and anesthesiologist are aware of what client issues? (Select all that apply.)

• Abnormal lab values • Drug allergies • Drug idiosyncrasies The nurse should review the client's chart and flag it for known or suspected drug allergies, drug idiosyncrasies, and abnormal lab values. Though important, it is not necessary to flag the names of the client's significant others or the client's occupation.

What are responsibilities of the nurse when local injectable anesthesia is to be administered to a client? (Select all that apply.)

• Preparing the area to be anesthetized. • Explaining how the anesthetic will be administered. • Applying a dressing to the area if appropriate. • Taking the patient's allergy history. The nurse is responsible for taking the patient's allergy history, explaining how the anesthetic will be administered, preparing the area to be anesthetized, and applying a dressing to the area if appropriate. The physician administers the local injectable anesthetic.