Anticonvulsant Therapy Ch 14 Pharm

The nurse is preparing to administer phenobarbital. The order reads: "Give phenobarbital, IV, 2 mg/kg/day at 0900." The patient weighs 253 pounds. How many milligrams will the patient receive for each dose?

230 mg per dose

What age do febrile seizures occur?

6 months to 5 years and by definition are caused by fever.

What is a seizure?

A brief episode of abnormal electrical activity in the nerve cells of the brain, which may or may not lead to a convulsion.

What is epilepsy?

A general term for any of a group of neurologic disorders characterized by recurrent episodes of convulsive seizures, sensory disturbances, abnormal behavior, loss of consciousness, or any combination of these.

What is an Electroencephalogram (EEG)?

A recording of the electrical activity that arises from spontaneous currents in nerve cells in the brain.

What is a convulsion?

A type of seizure involving excessive stimulation of neurons in the brain and characterized by the spasmodic contraction of voluntary muscles.

What do you do if a skin rash develops in a child or infant taking phenytoin?

Discontinue the drug immediately and notify the prescriber.

Side effects to phenytoin may include the following:

Drowsiness, lethargy, insomnia, confusion, slurred speech, irritability, headache, muscle twitching. Gingival hyperplasia Constipation, dizziness, nausea Hirsutism, coarsening of facial features Hypersensitivity reaction (fever, rash, lymphadenopathy)

Why is it important to monitor a patient's serum drug levels and make sure to maintain serum drug levels within therapeutic ranges?

For one, it helps not only to control seizures but also to reduce adverse effects. It also provides a useful guideline in assessing the effectiveness of and adherence to therapy. For example, if a patient has a very low serum level, it may mean the patient is not taking the medication as prescribed. If the level is above normal, the nurse needs to contact the prescriber before giving the next dose.

What are some contraindications for phenytoin?

Hypersensitivity to hydantoins Concurrent use of delavirdine Intravenous (IV) (additional) Second- and third-degree AV block Sinoatrial block Sinus bradycardia Adams-Stokes syndrome

Measurements of serum levels of the specific antiepileptic drug are ordered at baseline or at the start of therapy and frequently thereafter to determine what?

If subsequent serum levels are subtherapeutic, therapeutic, or toxic. Subtherapeutic levels indicate that the dosage may need to be increased (by the prescriber), and toxic levels require withholding or decreasing the dose—but only if prescribed!

What are benzodiazepines, barbiturates, and valproic acid's mechanism of action?

Increase the action of gamma-aminobutyric acid (GABA), which inhibits neurotransmitters throughout the brain.

Is phenytoin safe to use during pregnancy?

Phenytoin is teratogenic and should only be used as a last resort for seizure control during pregnancy.

What are cautions for phenytoin?

Porphyria Renal/hepatic impairment Those at increased risk for suicidal behavior/thoughts Older adult/debilitated patients Low serum albumin Underlying cardiac disease Hypothyroidism Patients of Asian descent

What do you assess for if there has been evidence of any type of seizure activity?

The occurrence of an aura, precipitating events, location of symptoms, duration, frequency, and intensity. Other warning signs may include depression, irritability, sleep disruption, nausea, and headache.

What is an example of educating the patient about the sedating effects?

The patient is not to drive, operate heavy machinery, or make major decisions until steady state is achieved or as instructed by the prescriber.

How do anti-seizure drugs work?

They stabilize nerve cell membranes and suppress the abnormal electric impulses in the cerebral cortex. These drugs prevent seizures but do not eliminate the cause or provide a cure. Anti-seizure drugs are classified as central nervous system (CNS) depressants.

What is the classification of valproic acid?

Valproate

What is status epilepticus?

When multiple seizures occur with no recovery between them. If appropriate therapy is not started promptly, hypotension, hypoxia, brain damage, and death can quickly ensue. Thus, status epilepticus is considered a true medical emergency!!!!

Absence seizures involve ....

a brief loss of awareness that commonly occurs with repetitive spasmodic eye blinking for up to 30 seconds. This type occurs primarily in childhood and rarely after 14 years of age.

The nurse is teaching a patient about the administration of phenytoin and instructs the patient to perform which action in case of a rash? a. "Contact your health care provider immediately." b. "Apply a topical corticosteroid to the rash." c. "Take diphenhydramine to minimize itching." d. "Contact the health care provider to discuss an antibiotic."

a. "Contact your health care provider immediately."

A patient asks the nurse about ways to prevent gingival symptoms while taking phenytoin. Which activity will the nurse recommend? a. Use a soft-bristled toothbrush. b. Floss the teeth three times daily. c. Brush the teeth and gums vigorously. d. Use toothpicks to clean under the gums.

a. Use a soft-bristled toothbrush.

Drugs used for epileptic seizures are called

anti-seizure drugs, anticonvulsants, or antiepileptic drugs (AEDs).

A patient with complex partial seizures is prescribed phenytoin to control recurrent seizures, but the patient reports being reluctant to take the drug long term because of its side effects. Which information would the nurse provide this patient? a. "Tolerance to most phenytoin side effects will develop over time." b. "Ask your health care provider about reducing your phenytoin dosage to minimize side effects." c. "Ask your health care provider about stopping your phenytoin if the side effects become troublesome." d. "Ask your health care provider about the possibility of using a different class of anti-seizure medication."

d. "Ask your health care provider about the possibility of using a different class of anti-seizure medication."

The nurse is providing education for a patient who will be taking an antiepileptic drug for the first time. Which statement by the patient indicates that further teaching is indicated? a. "I will take the medicine at the same time every day." b. "I will check with my doctor before taking any over-the-counter drugs." c. "I will keep the appointments to check my bloodwork." d. "I can drive to work again once my drug levels are normal."

d. "I can drive to work again once my drug levels are normal."

An older adult patient who weighs 70 kg is in status epilepticus. Which dose is an appropriate loading dose of phenytoin for this patient? a. 120 mg b. 240 mg c. 270 mg d. 450 mg

d. 450 mg

The nurse is assessing a newly admitted patient who has a history of seizures. During the assessment, the patient has a generalized seizure that does not stop for several minutes. The nurse expects that which drug will be ordered for this condition? a. valproic acid b. neurontin c. carbamazepine d. diazepam

d. diazepam

What are some medications that phenytoin is incompatible with?

diltiazem, dobutamine, enalapril, heparin, hydromorphone, insulin, lidocaine, morphine, nitroglycerin, norepinephrine, potassium chloride, and propofol

A therapeutic response to antiepileptic drug therapy ...

does not mean that the patient has been cured of the seizures but only that seizure activity is decreased or absent.

Common adverse effects for valporic acid are

drowsiness; nausea, vomiting, and other GI disturbances; tremor; weight gain; and transient hair loss

The most serious adverse effects for valporic acid are

hepatotoxicity and pancreatitis

Focal onset seizures originate ....

in a localized, or focal region (e.g., one lobe), of the brain.

Tonic-clonic seizures begin with .....

muscular contraction throughout the body (tonic phase) and progress to alternating contraction and relaxation (clonic phase).

Generalized onset seizures, formerly called grand mal seizures, are characterized by .......

neuronal activity that originates simultaneously in the gray matter of both hemispheres. There are several subtypes of generalized seizures.

Avoid rapid IV infusions because ...

of the risk for cardiac and/or respiratory arrest.

What are the two ways that phenytoin can be administered?

orally and intravenously

Older adult patients may experience ....

paradoxical reactions to antiepileptic drugs, resulting in hyperactivity and irritability versus sedation.

What was the first anticonvulsant used to treat seizures?

phenytoin It is still the most commonly used drug for controlling seizures.

Epilepsy without an identifiable cause is known as

primary epilepsy or idiopathic epilepsy. Primary epilepsy accounts for roughly 50% of cases.

Many anti-epileptic drugs are also used to treat other types of illnesses, including .....

psychiatric disorders, migraine headaches, and neuropathic pain syndromes.

With any of the antiepileptic drugs, the patient needs to understand the importance of ...

reporting any suicidal thoughts or ideas immediately.

The most common adverse effect of phenobarbital is

sedation.

A patient prescribed phenytoin reports using over-the-counter medications to treat acid reflux. Which response by the nurse is correct? a. "You should take a lower dose of phenytoin while using antacids." b. "Use an antacid that does not contain calcium." c. "Stop taking the phenytoin immediately if increased acid reflux occurs." d. "This combination may lead to increased central nervous system depression."

b. "Use an antacid that does not contain calcium."

The nurse is preparing to give medications. Which is an appropriate nursing action for intravenous (IV) phenytoin? (Select all that apply) a. Give IV doses via rapid IV push. b. Administer in normal saline solutions. c. Administer in dextrose solutions. d. Use a filter for IV infusions. e. Ensure continuous infusion of the drug.

b. Administer in normal saline solutions. d. Use a filter for IV infusions.

The nurse is preparing to administer a dose of intravenous phenytoin to a patient and notes that the patient's serum phenytoin level is 25 mcg/mL. Which action would the nurse take? a. Request a prescription for oral phenytoin. b. Hold the dose and notify the health care provider. c. Give the dose and observe closely for central nervous system (CNS) side effects. d. Notify the health care provider to discuss increasing the phenytoin dose.

b. Hold the dose and notify the health care provider.

The nurse would teach a patient with diabetes who is taking phenytoin to monitor for which condition? a. Hypoglycemia b. Hyperglycemia c. Increased drug effects d. Decreased drug effects

b. Hyperglycemia

A patient calls the clinic 1 week after beginning therapy with phenytoin to report urine that is pinkish red. How would the nurse respond? a. Have the patient come to the clinic for a dipstick urinalysis. b. Reassure the patient that this is a harmless side effect of phenytoin. c. Contact the health care provider and request a prescription for a blood urea nitrogen (BUN) and creatinine. d. Tell the patient to stop the drug immediately and contact the health care provider.

b. Reassure the patient that this is a harmless side effect of phenytoin.

The nurse is performing an admission assessment on a patient who will receive intravenous phenytoin. The patient reports a history of a "slow heart rate." Which action by the nurse is appropriate? a. Administer the medication as prescribed. b. Request an electrocardiogram (ECG). c. Count the apical pulse for 1 minute before giving the drug. d. Request an oral form of the drug to minimize cardiovascular side effects.

b. Request an electrocardiogram (ECG).

A patient who has been taking phenytoin for several years reports stopping the drug the day before admission to the hospital. Which condition is most important for the nurse to monitor for in this patient? a. Fever or bruising b. Status epilepticus c. Ataxia and nystagmus d. Increased serum glucose

b. Status epilepticus

The nurse is reviewing the drugs currently taken by a patient who will be starting drug therapy with carbamazepine. Which drug may raise a concern for interactions? a. digoxin b. acetaminophen c. diazepam d. warfarin

b. acetaminophen

The nurse is caring for a patient who is experiencing excessive drowsiness caused by phenytoin. The health care provider withholds the drug and orders a serum drug level. How long will the nurse expect to monitor this patient for drowsiness? a. 30 to 60 minutes b. 12 hours c. 24 to 42 hours d. 7 to 10 days

c. 24 to 42 hours

Through which action does phenytoin exert its effects? a. By eliminating the underlying causes of seizure disorders. b. By increasing the action of gamma-aminobutyric acid (GABA), which inhibits neurotransmitters throughout the brain. c. By suppressing sodium influx and prolonging the channel inactivation to prevent neuron firing. d. By suppressing the calcium influx to prevent the electric current generated by the calcium ions to the T-type calcium channel.

c. By suppressing sodium influx and prolonging the channel inactivation to prevent neuron firing.

Which patient laboratory values will the nurse review before initiating therapy with phenytoin? Select all that apply. a. Arterial blood gases b. Serum electrolytes c. Liver function tests (LFTs) d. Blood urea nitrogen (BUN) and serum creatinine e. Complete blood count (CBC)

c. Liver function tests (LFTs) d. Blood urea nitrogen (BUN) and serum creatinine e. Complete blood count (CBC)

The nurse understands that phenytoin should be used with caution in patients with which comorbid conditions? Select all that apply. a. Hirsutism b. Gingival hyperplasia c. Porphyria d. Hypothyroidism e. Cardiac disease

c. Porphyria d. Hypothyroidism e. Cardiac disease

Through which mechanism of action do antiseizure drugs work? a. They decrease the inhibitory neurotransmitter system in the brain called the gamma-aminobutyric acid (GABA) system. b. They increase calcium influx in the brain, causing a decrease in electrical current flow. c. They stabilize nerve cell membranes and suppress the abnormal electrical impulses in the cerebral cortex. d. They bind to opioid receptors, and molecular signaling activates the receptors to mediate certain actions.

c. They stabilize nerve cell membranes and suppress the abnormal electrical impulses in the cerebral cortex.

When monitoring and evaluating the effects of antiepileptic drugs ...

constantly assess the patient for changes in mental status/level of consciousness, affect, eye problems, or visual disorders.

Things to monitor for when patients take anti-seizure medication:

signs or symptoms of depression, suicidal tendencies, and unusual behavior CBC with differential, renal function, liver function test (LFT), and blood pressure (BP) (with IV use). Repeat CBC 2 weeks after initiation of therapy and 2 weeks after administration of maintenance dose therapeutic serum level (10 to 20 mcg/mL); toxic serum level is greater than 20 mcg/mL assist with ambulation if drowsiness or lethargy occurs Evaluate the patient frequently for physical symptoms, and follow laboratory values for changes related to the medication observe frequently for recurrence of seizure activity. Assess for clinical improvement (decrease in intensity/frequency of seizures)

These classes of medications have other indications ...

such as management of chronic pain and migraines, so the existing problem or disorder would show improvement with minimal adverse effects.

What is the classification of phenytoin?

Anti-convulsant, Hydantoin

What is the classification of diazepam, and clonazepam?

Benzodiazepines

Adverse effects to phenytoin may include the following:

Abrupt withdrawal may precipitate status epilepticus. Blood dyscrasias, lymphadenopathy, and osteomalacia (due to interference of vitamin D metabolism) may occur. Toxic phenytoin blood concentration (25 mcg/mL or more) may produce ataxia (muscular incoordination), nystagmus (rhythmic oscillation of eyes), and diplopia. As level increases, extreme lethargy to comatose state occurs. Suicidal tendencies. Cardiac arrest, ventricular fibrillation, bradycardia. Agranulocytosis, leukopenia, aplastic anemia, thrombocytopenia, megaloblastic anemia. Lupus erythematosus, Stevens-Johnson syndrome, toxic epidermal necrolysis.

What is the classification of phenobarbital, mephobarbital, and primidone?

Long-acting barbiturates

How do you administer phenytoin as an IV dose?

May give undiluted or may dilute with 0.9% NaCl to a concentration of 5 mg/mL or more. Administer 50 mg over 1 min in adults, 20 mg/min in older adults with preexisting cardiovascular conditions. In neonates, administer at a rate not exceeding 1 to 3 mg/kg/min. Severe hypotension or cardiovascular collapse can occur if rate of IV injection exceeds 50 mg/min for adults. IV toxicity is characterized by CNS depression and cardiovascular collapse. Because phenytoin must be administered slowly, a benzodiazepine (such as lorazepam) is typically given concurrently with the loading dose of phenytoin for quicker onset of action. *****Give by IV push or IV piggyback. IV push is very painful (chemical irritation of vein due to alkalinity of solution). To minimize effect, flush vein with sterile saline solution through the same IV needle and catheter after each IV push.*****

What assessments should you complete before starting a patient on anticonvulsant therapy?

Review history of seizure disorder (intensity, frequency, duration, loss of consciousness). Obtain a health history including current drugs and herbs the patient uses. Report and document any probable drug-drug or herb-drug interactions. Assess the patient's knowledge regarding medication regimen. Perform complete blood count (CBC) before beginning therapy and periodically during therapy. Check urinary output to determine whether adequate (>1500 mL/d). Determine laboratory values related to renal and liver function. If both blood urea nitrogen (BUN) and creatinine levels are elevated, a renal disorder should be suspected. Elevated serum liver enzymes (alkaline phosphatase, alanine aminotransferase, gamma-glutamyl transferase, 59-nucleotidase) indicate a hepatic disorder.

What should you do before giving anti-epileptic drugs?

Review laboratory test results, including red blood cell and white blood cell counts, clotting studies, and renal and/or liver function studies.

What is the classification of ethosuximide?

Succinimides

What are hydantoins, carbamazepine, and valproic acid's mechanism of action?

Suppress sodium influx through the drug binding to the sodium channel when it is inactivated, prolonging the channel in activation and thereby preventing neuron firing.

What are valproic acid, and succinimide's mechanism of action?

Suppress the calcium influx, preventing the electric current generated by the calcium ions to the T-type calcium channel.

Mr. Briggs is a 50-year-old man who presents to the emergency department with a first-time grand mal seizure; he is being admitted to the intensive care unit (ICU) for further monitoring and evaluation. Mr. Briggs' medical history includes hypertension, smoking, and hyperlipidemia. The nurse receives a report that the medical team stopped the seizure in the emergency department with 4 mg IV lorazepam, followed by a loading dose of 700 mg IV phenytoin. Mr. Briggs' current vital signs are HR 100, RR 22, BP 190/100, T 99.1, SaO2 96% 2 L oxygen, no pain reported currently. The patient is in a postictal (after seizure) state, and his wife is at the bedside. After Mr. Briggs recovers from the postictal state, the nurse provides phenytoin education. Which statement indicates Mr. Briggs understands the phenytoin education? Select all that apply. a. "I need to avoid drinking alcohol." b. "I will need to check in frequently with my health care provider to have my blood levels monitored." c. "I will try to improve my oral hygiene so my gums don't bleed." d. "I can take this medication whenever I have a seizure." e. "I am going to receive this medication via a shot in my muscle."

a. "I need to avoid drinking alcohol." b. "I will need to check in frequently with my health care provider to have my blood levels monitored." c. "I will try to improve my oral hygiene so my gums don't bleed."

Which substances interact with phenytoin to cause increased central nervous system (CNS) depression? Select all that apply. a. Alcohol b. Evening primrose c. Cimetidine d. Oral contraceptive drugs e. Calcium-containing antacids

a. Alcohol c. Cimetidine

Which response would the nurse expect to find in a patient with a phenytoin level of 25 mcg/mL? a. Ataxia b. Hypertension c. Seizures d. No unusual response; this level is therapeutic.

a. Ataxia

A patient who has type 2 diabetes mellitus (DM) will begin taking phenytoin to treat seizures. Which ongoing assessment will the nurse complete on this patient? a. Close monitoring of serum glucose b. Close monitoring for adverse central nervous system (CNS) effects c. More frequent assessment of oxygen saturation levels d. Monitor for subtherapeutic serum drug levels

a. Close monitoring of serum glucose

Through which mechanisms can anti-seizure drugs decrease seizure activities? Select all that apply. a. Diminishing calcium influx b. Suppressing sodium influx c. Increasing sodium channel activation d. Increasing the action of gamma-aminobutyric acid (GABA) e. Increasing the calcium ion current through the T-type channel

a. Diminishing calcium influx b. Suppressing sodium influx d. Increasing the action of gamma-aminobutyric acid (GABA)

A nurse would instruct patients taking phenytoin to report which side effects? Select all that apply. a. Fever b. Gastrointestinal (GI) upset c. Dizziness d. Bleeding gums e. Reddish-brown urine

a. Fever c. Dizziness d. Bleeding gums

Which condition is most likely to require lower dosing and closer monitoring to prevent drug toxicity in a patient taking phenytoin? a. Hepatitis b. Pneumonia c. Anemia d. Gastroesophageal reflux

a. Hepatitis

The nurse is administering an antiepileptic drug and will follow which guidelines? (Select all that apply) a. Monitor the patient for drowsiness. b. Medications may be stopped if seizure activity disappears. c. Give the medication at the same time every day. d. Give the medication on an empty stomach. e. Notify the prescriber if the patient is unable to take the medication.

a. Monitor the patient for drowsiness. c. Give the medication at the same time every day. e. Notify the prescriber if the patient is unable to take the medication.

A patient is taking pregabalin but does not have a history of seizures. The nurse recognizes that this drug is also indicated for which of these? a. Postherpetic neuralgia b. Viral infections c. Parkinson disease d. Depression

a. Postherpetic neuralgia

A patient who has a seizure disorder has begun taking phenytoin. To ensure effectiveness of the drug, which laboratory value will the nurse monitor? a. Serum drug levels b. Liver function tests c. Renal function tests d. Complete blood count (CBC)

a. Serum drug levels

At the beginning of a shift, the nurse assesses a 65-year-old patient who is receiving intravenous (IV) phenytoin and notes that the pump is programmed to deliver 50 mg/minute. Which action would the nurse take? Select all that apply. a. Stop the IV. b. Notify the health care provider. c. Increase the rate to 60 mg/minute. d. Request a prescription for an antihypertensive drug. e. Assess the patient's blood pressure and heart rate.

a. Stop the IV. b. Notify the health care provider. e. Assess the patient's blood pressure and heart rate.

A patient who is taking oral phenytoin reports experiencing heartburn and gastrointestinal (GI) upset. Which recommendation will the nurse provide to the patient? a. Take the medication with food. b. Take with a calcium-containing antacid. c. Take the medication on an empty stomach. d. Stop taking the medication and notify the health care provider.

a. Take the medication with food.

Things to teach a patient on anticonvulsants:

the importance of taking the medication as directed that urine may be a harmless pinkish red or reddish brown to maintain good oral hygiene and to use a soft toothbrush to prevent gum irritation and bleeding to report symptoms of sore throat, fever, bruising, and nosebleeds, which may indicate a blood dyscrasia to inform the health care provider of adverse reactions, such as gingivitis, nystagmus, slurred speech, rash, and dizziness. (Stevens-Johnson syndrome begins with a rash.)********* patients with diabetes to monitor serum glucose levels more closely than usual because phenytoin may inhibit insulin release, causing an increase in glucose level to avoid alcohol because it is a CNS depressant **** for patients on phenytoin**** that blood levels will need to be monitored on a regular basis because phenytoin can reach toxic levels in the blood

Antiepileptic drugs must never be abruptly discontinued because ...

this may precipitate rebound seizure activity.

Seizures are classified based on what?

where the seizures begin in the brain, the level of awareness during the seizure, and other features of seizures. The three major classifications of seizures are generalized onset, focal onset, and unknown onset