NAPLEX - Epilepsy McGraw Hill

You get a call from a provider asking about the occurrence of vision loss with Sabril. They tell you the suspect this serious adverse drug event has occurred in a patient. Where should this event be reported?

A

Food and Drug Administration (FDA) MedWatch

B

Centers for Disease Control and Prevention

C

PubMed

D

National Library of Medicine

A

Serious adverse effects should be reported to FDA MedWatch.

Answers b, c, and d are incorrect. None of these would be appropriate for adverse drug event reporting.

WW is a 56-year-old hospitalized patient taking the following medications: cefepime, metoprolol succinate, levothyroxine, and acetaminophen. The patient developed seizures. Select the possible drug-induced cause(s) of seizures.

A

Levothyroxine

B

Acetaminophen

C

Cefepime

D

Metoprolol

C

Cefepime has been linked to seizures and nonconvulsive status epilepticus, a risk that is increased in patients with renal impairment and in patients with a history of a seizure disorder. Dosage adjustments are necessary. Other medications associated with development of seizures include tramadol, bupropion, theophylline, some antidepressants, some antipsychotics, amphetamines, cocaine, imipenem, lithium, excessive doses of penicillins or cephalosporins, sympathomimetics, and stimulants.

Answers a, b and d are incorrect. None of these agents are associated with causing seizures.

You get a call from a provider asking about the occurrence of vision loss with Sabril®. They tell you the suspect this serious adverse drug event has occurred in a patient. You are asked to substitute the oral solution packets for the tablets because your patient has a hard time swallowing tablets. You look in the Food and Drug Administration (FDA) Orange Book for information and this is what you find. What do you do based on this information?

A

Substitute the product without calling the physician; the products are therapeutic equivalents.

B

Call the physician to ask about switching products; they are not therapeutic equivalents.

C

Substitute the product without calling the physician; the products are pharmaceutical equivalents.

D

Call the physician to ask about switching products; they are therapeutic equivalents.

B

The physician would need to be called in order to make this switch because the products are not pharmaceutical or therapeutic equivalents.

Answers a, c and d are incorrect. These products are not therapeutic equivalents because they are not pharmaceutical equivalents. In order for drugs to be therapeutic equivalents they must be (a) approved as safe and effective, (b) be pharmaceutic equivalents, and (c) bioequivalent. In order for drugs to be pharmaceutic equivalents they must (a) contain identical amounts of the same active drug ingredient in the same dosage form and route of administration, and (b) meet compendial or other applicable standards of strength, quality, purity, and identity.

Select the antiseizure drug (ASD) that is associated with the idiosyncratic adverse effect of gingival hyperplasia.

A

Phenobarbital

B

Primidone

C

Tiagabine

D

Phenytoin

D

.Phenytoin is associated with gingival hyperplasia (gum overgrowth).

Answers a, b, and c are incorrect. Those ASDs are not associated with gingival hyperplasia. Note:Primidone is rarely used; however, it is important because it is metabolized to two active metabolites, one of which is phenobarbital.

A physician tells you she would like to begin lamotrigine in a patient in order to avoid some drug interactions with other antiseizure drugs (ASDs), but she would like to know if there are any other adverse effects she should educate the patient about. Which of the following should be addressed with the patient?

A

Rash

B

Edema

C

Pancreatitis

D

Alopecia

A

Rash is an idiosyncratic reaction associated with lamotrigine. Patients should be aware of the possibility of hypersensitivity reactions. Recently, a serious immune-related reaction, hemophagocytic lymphohistiocytosis (HLH) has been reported to the Food and Drug Administration (FDA), and may result in serious complications. Early recognition (high fever) and treatment is necessary to prevent further complications. If a patient experiences rash, the drug should be discontinued unless it was clearly caused by something else.

Rxprep lists alopecia as an AE for lamotrigine

Answer b is incorrect. Gabapentin and pregabalin are associated with development of pedal edema.

Answers c and d are incorrect. Lamotrigine is not associated with development of pancreatitis or alopecia. Valproic acid has been linked to both of these effects.

Which of the following medications is approved for adjunctive treatment of Dravet syndrome? Select all that apply.

A

Cannabidiol

B

Carbamazepine

C

Stiripentol

D

Phenytoin

ACD

Cannabidiol and stiripentol have both been recently approved (2018) for adjunctive treatment of seizures related to Dravet syndrome in patients 2 years of age and older.

Answers b and d are incorrect. Phenytoin and carbamazepine are not recommended for treatment of Dravet syndrome.

A physician asks you about antiseizure medication for a 19-year-old female patient with generalized tonic-clonic seizures. The patient is concerned about gaining weight and developing polycystic ovarian syndrome (PCOS), since she has a friend with this condition. Which of the following ASDs has been associated with PCOS in female patients? Select all that apply.

A

Topiramate

B

Lamotrigine

C

Valproate

D

Carbamazepine

C

Valproate is recommended for treatment of generalized tonic-clonic seizures, and is associated with weight gain and development of PCOS, particularly in females younger than 20 years and in overweight patients.

Answers a, b, and d are incorrect.Topiramate, lamotrigine, and carbamazepine are all indicated for treatment of generalized tonic-clonic seizures; however, do not have a chronic side effect of weight gain or PCOS. Topiramate has been associated with weight loss. The main concern with lamotrigine treatment is rash and development of immune-related adverse effects, such as hemophagocytic lymphohistiocytosis (HLH).

A patient is admitted to the hospital with seizures that result in a sudden interruption of activities and a blank stare. What type of seizure disorder is this?

A

Absence seizures

B

Tonic-clonic

C

Myoclonic

D

Atonic

A

Absence seizures or petit mal result in sudden interruption of activities and a blank stare.

Answer b is incorrect. Tonic-clonic seizures or grand mal result in alternating muscle contractions and jerking.

Answer c is incorrect. Myoclonic seizures result in brief shock-like contractions of a muscle group.

Answer d is incorrect. Atonic seizures result in sudden loss of muscle tone ("drop attacks").

JW is a 29-year-old woman presenting to the pharmacy with a new prescription for phenytoin. She is currently not taking any other medications. A year later JW tells you she wants to become pregnant and would like to change to a different antiepileptic drug (AED) that might be safer during pregnancy. What is important to discuss with her and her physician in regards to switching therapy?

A

Her current medication should be stopped immediately in order to ensure the current antiseizure drug (ASD) has been fully removed out of her system prior to getting pregnant.

B

Her existing ASD can be stopped abruptly and the new ASD should be started at a low dose and titrated up to the target dose.

C

Her new ASD should be initiated at a low dose and titrated up to become minimally effective at which time the existing ASD can be gradually tapered.

D

She should avoid pregnancy altogether and remain on her current ASD therapy.

C

Switching ASDs requires a titration process because abrupt discontinuation of an ASD may lead to breakthrough seizures. The process requires starting the new ASD at a low dose and titrating up to the minimal effective dose. Once the minimal effective dose is reached, the drug to be discontinued is gradually tapered, while the dose of the new ASD continues to be increased to the target dose

Answers a and b are incorrect. ASDs should not be abruptly discontinued as they can precipitate a seizure. Patients who are seizure-free may desire to discontinue their medication. Factors favoring successful withdrawal of ASDs include a seizure-free period of 2 to 4 years, complete seizure control within 1 year of onset, an onset of seizures after age 2 but before age 35, and a normal neurologic examination and electroencephalogram (EEG). Withdrawal of ASDs is done slowly with a dose tapered over at least 3 months.

Answer d is incorrect. A patient who has a seizure disorder and desires to become pregnant should discuss the benefits and risks of drug therapy collaboratively with their health care provider to determine the best way to minimize risks to the patient and baby.

GG is a 67-year-old woman on carbamazepine for her seizure disorder. Her family is worried about serious side effects because of her age. Which of the following are idiosyncratic adverse reaction(s) associated with use of carbamazepine? Select all that apply.

A

Aplastic anemia

B

Hyponatremia

C

Rash

D

Colitis

ABC

Aplastic anemia, hyponatremia, and rash are idiosyncratic reactions. Because idiosyncratic reactions may be life-threatening, the antiseizure drug (ASD) may require discontinuation. Idiosyncratic reactions are associated with an immunologic reaction; therefore cross-reactivity among ASDs is possible.

Answer d is incorrect.Carbamazepine is not associated with the development of colitis (eg, Clostridium difficile colitis).

BH is a 47-year-old man in status epilepticus in need of drug therapy. Intravenous dosing of phenytoin cannot be infused faster than 50 mg/min. Select the adverse reactions that are associated with infusions faster than 50 mg/min.

A

Hypotension

B

Gingival hyperplasia

C

Anemia

D

Rash

A

The dose cannot be infused faster than 50 mg/min due to the potential risks of hypotension and arrhythmias.

Answers b, c, and d are incorrect. Gingival hyperplasia, anemia, and rash are idiosyncratic reactions and not related to infusion rates or dose.

JW is a 29-year-old woman presenting to the pharmacy with a new prescription for phenytoin. She is currently not taking any other medications. What should this patient be counseled about in relation to her new drug therapy? Select all that apply.

A

Avoid alcohol while taking this medication.

B

Use appropriate barrier methods of contraception.

C

Wear sunscreen. This medication is associated with increased photosensitivity.

D

Take this medication with food at the same time every day.

AB

Alcohol should be avoided because it can inhibit the metabolism of phenytoin and increase central nervous system (CNS) depression. Phenytoin can also interact with oral contraceptives and decrease their effect, so barrier methods of contraception are recommended. In general, all women of child-bearing age with a seizure disorder should be counseled about the risks of getting pregnant and the need for appropriate counseling and prenatal care if pregnancy is planned.

Answers c and d are incorrect. Phenytoin is not associated with increase sun sensitivity. Also, food can decrease phenytoin absorption and though it is important to take the medication every day, the timing of administration is not a factor in achieving therapeutic goals.

Select the treatable cause(s) of seizures. Select all that apply.

A

Hypoglycemia

B

Altered electrolytes

C

Infections

D

Genetic defects

ABC

Hypoglycemia, altered electrolytes, and infections are treatable causes of seizures. A seizure produced by treatable causes does not represent epilepsy. Note: medications that cause hypoglycemia and altered electrolytes could indirectly precipitate a seizure.

Answer d is incorrect. Genetic defects do not represent a treatable cause as they are not something modifiable.

Note: The underlying etiology of epilepsy is unknown in 80% of patients. The most common recognized causes of epilepsy are head trauma and stroke. Central nervous system tumors, infections, metabolic disturbances (hyponatremia and hypoglycemia), neurodegenerative diseases, and medications represent other causes.

You read a clinical study for a new antiepileptic medication that has strong data to support its efficacy against other antiseizure drugs (ASDs). The treatment duration studied was 18 weeks. However, clinical studies have shown the following data related to safety:

Adverse Effect

Serious arrhythmia

Placebo (N=260)

1%

New Drug (N=258)

5%

What is the number needed-to-harm (NNH) related to arrhythmia?

A

4

B

20

C

25

D

8

C

NNH is calculated as 1/risk difference. In this case, the difference in risk between placebo and the new drug is 5%-1% = 4%. 1 / 0.04 = 25. This means that for every 25 patients treated with the new drug one will experience a serious arrhythmia over the course of 18 weeks of treatment.

SB is a patient with newly diagnosed complex seizure disorder. His physician has noted that he is taking warfarin for atrial fibrillation and also has restless leg syndrome. For this reason, he would like to avoid an antiseizure drug (ASD) that is a substrate and inducer of the CYP-450 2C9. Which of the following should be avoided in this patient? Select all that apply.

A

Phenytoin

B

Phenobarbital

C

Carbamazepine

D

Levetiracetam

ABC

.Phenytoin, phenobarbital, carbamazepine are all substrates and inducers of the CYP-450 2C9.

Answer d is incorrect.Levetiracetam is not a substrate or inducer and is renally eliminated.

Which drug(s) for status epilepticus can be given intramuscularly?

A

Phenytoin

B

Lamotrigine

C

Diazepam

D

Fosphenytoin

D

Fosphenytoin is a water-soluble, prodrug of phenytoin that is rapidly converted to phenytoin in the body. Unlike phenytoin, fosphenytoin is compatible with most intravenous solutions and is tolerated as an intramuscular injection.

Answer a is incorrect. Phenytoin cannot be administered intramuscularly. Phenytoin should not be administered via the intramuscular route due to alkaline nature.

Answer b is incorrect. Lamotrigine is not appropriate to use to treat status epilepticus.

Answer c is incorrect. Diazepam is recommended for treating status epilepticus but should be used intravenously. It is also available as a rectal preparation if no intravenous access exists.

SB is a patient with newly diagnosed complex seizure disorder. His physician has noted that he is taking warfarin for atrial fibrillation and also has restless leg syndrome. For this reason, he would like to avoid an antiseizure drug (ASD) that is a substrate and inducer of the CYP-450 2C9. Which of the following would be the best option for this patient based on the information presented?

A

Gabapentin

B

Levetiracetam

C

Carbamazepine

D

Ethosuximide

A

Gabapentin is renally eliminated and does not have interactions via the CYP-450 pathway. It can also be used to treat restless leg syndrome.

Answer b is incorrect. Though levetiracetam is renally eliminated, it is not the best option for this patient given the fact that gabapentin can also help treat her other condition (rest less leg).

Answer c is incorrect. Carbamazepine is a CYP-450 2C9 substrate and inducer which could decrease the effects of warfarin.

Answer d is incorrect. Ethosuximide is not indicated for treating complex seizures. It is indicated for treating absence seizures.

Select the dose-related adverse reaction(s) of antiseizure drugs (ASDs). Select all that apply.

A

Neutropenia

B

Sedation

C

Thrombocytopenia

D

Ataxia

BD

Sedation is a dose-dependent adverse reaction. Other dose-dependent adverse reactions include ataxia and diplopia.

Answer a is incorrect. Neutropenia (hematologic toxicity) is an idiosyncratic reaction and not related to dose or concentration.

Answer c is incorrect. Thrombocytopenia (hematologic toxicity) is an idiosyncratic reaction and not related to dose or concentration. Other idiosyncratic reactions include rash and hepatotoxicity.

DD is an elderly male currently on phenytoin. He has begun experiencing confusion and nystagmus in the past week. His last serum creatinine was 3.6 mg/dL, albumin 2.4 g/dL. His only other medications are aspirin and omeprazole. What could this be a symptom of?

A

Aura before seizure onset

B

Lack of seizure control

C

Phenytoin toxicity

D

Normal side effects of the drug

C

Phenytoin is highly protein-bound. The usual total (bound and unbound) concentration for phenytoin is 10 to 20 μg/mL; however, the unbound (free) concentration is 1 to 2 μg/mL. The unbound concentration is the component that produces seizure control and adverse reactions. Symptoms of phenytoin toxicity include confusion, nystagmus, blurred vision, diplopia, and slurred speech.

Answers a, b and d are incorrect. The symptoms this patient is experiencing are not indicative of uncontrolled seizure disorder. Nystagmus is not a normal side effect from taking phenytoin but can be indicative of drug toxicity.

Select the patient population or condition that often leads to fast titration of antiseizure drugs (ASDs).

A

Switching ASDs

B

Discontinuing ASDs

C

Children

D

Women of child-bearing potential

C

Children require prompt control of seizures to avoid interference with development of the brain and cognition. ASD doses are increased rapidly and frequent changes in the regimen are made to maximize control of seizures. Due to high metabolic rates in children, doses of ASDs are higher on a milligram per kilogram basis compared to adults.

Answer a is incorrect. Switching ASDs requires a titration process, because abrupt discontinuation of an ASD may lead to breakthrough seizures. The process requires starting the new ASD at a low dose and titrating up to the minimal effective dose. Once the minimal effective dose is reached, the drug to be discontinued is gradually tapered, while the dose of the new ASD continues to be increased to the target dose.

Answer b is incorrect. Epilepsy is considered a lifelong disorder; however, patients who are seizure-free may desire to discontinue their medication. Withdrawal of ASDs is done slowly with a dose tapered over at least 3 months.

Answer d is incorrect. Women of child-bearing potential or who are pregnant have recommendations for ASD management because several ASDs have been implicated in minor and serious birth defects. The majority of pregnant epileptic patients receiving ASDs produce a normal infant, but special recommendations must be followed. Recommendations include: use monotherapy when possible; use lowest dose possible to control seizures; monitor ASD serum concentrations at the start of pregnancy and monthly thereafter; give supplemental folic acid 1 to 4 mg daily to all women of child-bearing potential; administer supplemental vitamin K during the eighth month of pregnancy to women receiving enzyme-inducing ASDs.

A patient is admitted to the hospital with seizures that result in a sudden interruption of activities and a blank stare. What is the recommended first-line treatment for this type of seizure disorder?

A

Phenytoin

B

Felbamate

C

Levetiracetam

D

Ethosuximide

D

Ethosuximide is the first-line treatment for absence seizures.

Answers a, b and c are incorrect. None of these drugs treat absence seizures.

Select the antiseizure drug (ASD) that is available in oral and parenteral formulations. Select all that apply.

A

Neurontin

B

Dilantin

C

Keppra

D

Trileptal

BC

.Phenytoin (Dilantin) and levetiracetam (Keppra) is available in oral and parenteral formulations.

Answers a and d are incorrect. They are available in oral formulations only.

DD is an elderly male currently on phenytoin. He has begun experiencing confusion and nystagmus in the past week. His last serum creatinine was 3.6 mg/dL, albumin 2.4 g/dL. His only other medications are aspirin and omeprazole. What could be contributing to the development of these symptoms? Select all that apply.

A

Drug interaction

B

Low albumin

C

Renal impairment

D

Not taking the medication

BC

Low albumin and renal impairment can lead to more free (unbound drug) drug resulting in signs and symptoms of drug toxicity.

Answer a is incorrect. Neither aspirin nor omeprazole is known to increase the concentration of phenytoin.

Answer d is incorrect. The patient is experiencing symptoms of drug toxicity, not symptoms of uncontrolled seizure disorder.

A physician asks you for a recommendation to treat a 47-year-old man with generalized tonic-clonic seizures. Which of the following medications could you recommend?

A

Brivaracetam

B

Zonisamide

C

Lamtrogine

D

Ethosuximide

C

:Lamotrigine is recommended for generalized tonic-clonic seizures.

Answers a, b, and d are incorrect. Brivaracetam and zonisamide are both recommended for focal seizures. Ethosuximide is recommended for generalized absence seizures.

BH is a 47-year-old man in status epilepticus in need of drug therapy. Intravenous dosing of phenytoin cannot be infused faster than 50 mg/min. What is the water-soluble prodrug of phenytoin that is rapidly converted to phenytoin in the body and can be used as an alternate?

A

Trileptal

B

Tegretol

C

Cerebyx

D

Dilantin

C

Cerebyx is fosphenytoin, which is a prodrug of phenytoin. It is compatible with most intravenous solutions and is tolerated as an intramuscular injection. Fosphenytoin is dosed on phenytoin equivalents (PE), and it can be infused up to 150 mg PE/min. Although fosphenytoin has fewer cardiovascular side effects compared to phenytoin, blood pressure, and electrocardiogram (ECG) should still be monitored.

Answer a is incorrect. Trileptal is oxcarbazepine.

Answer b is incorrect. Tegretol is carbamazepine.

Answer d is incorrect. Dilantin is phenytoin.

JW is a 29-year-old woman presenting to the pharmacy with a new prescription for phenytoin. She is currently not taking any other medications. Select the goal therapeutic level for phenytoin in this patient.

A

4 to 12 mcg/mL.

B

10 to 20 mcg/mL.

C

50 to 100 mcg/mL.

D

No therapeutic drug monitoring is required with this drug.

B

Phenytoin's usual total serum concentration is 10 to 20 mcg/mL.

Answer a is incorrect.Carbamazepine's usual serum concentration is 4 to 12 mcg/mL.

Answer c is incorrect. Valproic acid's usual serum concentration is 50 to 100 mcg/mL.

Answer d is incorrect. Serum concentrations of phenytoin should be monitored.

What is the mechanism of action for the antiseizure drug (ASD) carbamazepine?

A

Sodium channel modulator

B

Potassium channel blocker

C

Calcium channel blocker

D

Gamma-aminobutyric acid (GABA) uptake inhibitor

A

Carbamazepine is a sodium channel modulator.

Answers b, c, and d are incorrect. No ASD mechanisms for efficacy are targeted to potassium channels. Valproic acid, ethosuximide, and lamotrigine are calcium channel blockers. Rxprep says lamotrigine is Na