Pharm Ch 14: Seizure Disorders - Study Questions

Performing laboratory tests is necessary to monitor patients who are taking carbamazepine. The dental team should observe the oral cavity for petechiae or signs of infections. a. Both the statement and the reason are correct and related. b. Both the statement and the reason are correct, but they are not related. c. The statement is correct, but the reason is not. d. The statement is not correct, but the reason is accurate. e. Neither the statement nor the reason is correct.

ANS: A Carbamazepine can cause blood dyscrasias, which can cause clotting disturbances (petechiae) and compromise immune function (increase infections). The white blood cell count should be monitored. The dental team should look for petechiae or signs of infection. Fatal blood dyscrasias, including aplastic anemia and agranulocytosis, have been reported related to carbamazepine therapy. Patients should be made aware of these symptoms of blood dyscrasias and warned to stop the drug and report any of the symptoms immediately.

Gingival enlargement as a consequence of phenytoin therapy most commonly affects the _____ facial gingiva. a. maxillary anterior b. maxillary posterior c. mandibular anterior d. mandibular posterior

ANS: A Gingival enlargement is most commonly seen in the maxillary anterior facial area. Hyperplasia is more commonly located in the anterior rather than the posterior surfaces and the buccal rather than lingual surfaces. The affected areas of the mouth in order of severity are the maxillary anterior facial, mandibular anterior facial, maxillary posterior facial, and mandibular posterior facial areas. Both normal and abnormal tissue may be found in the affected person.

Which of the following antiepileptic drugs is commonly used as monotherapy for partial onset and generalized tonic-clonic seizures and may be effective for children with Lennox-Gastaut syndrome? a. Levetiracetam (Keppra) b. Carbamazepine (Tegretol) c. Oxcarbazepine (Trileptal) d. Phenytoin (Dilantin)

ANS: A Levetiracetam (Keppra) is used for partial onset and generalized tonic-clonic seizures and may be effective for children with Lennox-Gastaut syndrome and absence seizures. The benzodiazepine clobazam (Onfi) is used as an adjunctive treatment for seizures associated with Lennox-Gastaut syndrome in patients 2 years of age. Carbamazepine and oxcarbazepine are used to treat partial seizures. Phenytoin IV is used to treat status epilepticus.

Which of the following statements is true of absence seizures and tonic-clonic seizures? a. Both types of seizures involve the loss of consciousness. b. Consciousness returns gradually after an absence seizure, which is a major problem for the dental team. c. Tonic-clonic seizures are not treated with medication. d. Both A and B are true. e. Both B and C are true.

ANS: A The symptoms of absence seizures include a brief loss of consciousness with characteristic EEG waves and little movement. Generalized tonic-clonic seizures include longer periods of loss of consciousness and major motor activity of large muscles. Management of absence seizures poses no problems for the dental team. The team's main concern is the adverse reactions that can occur from long-term administration of the drugs used to treat the disease. Tonic-clonic seizures are treated with medication. Valproate, lamotrigine, and levetiracetam are considered the drugs of choice for treating generalized tonic-clonic seizures.

Which of the following are true regarding the dental management of patients taking antiepileptic agents? (Select all that apply.) a. Antiepileptic agents will exacerbate CNS depression due to other drugs. b. Antiepileptic agents may cause additive gastrointestinal adverse reactions. c. Antiepileptic agents may cause some other drugs to be metabolized more slowly causing cumulative effects. d. Antiepileptic agents will not interact with pain medications or antibiotics used in dentistry.

ANS: A, B CNS depression is additive with other drugs such as opioids, and additional CNS depressants should be used with caution. Antiepileptic agents will cause additive gastrointestinal adverse reactions, and drugs that will cause gastric irritation should be used cautiously. Antiepileptic drugs cause induction of hepatic microsomal enzymes. This causes certain drugs to be metabolized more quickly. Antiepileptic drugs can interact with dental drugs including propoxyphene and doxycycline.

Which of the following antiepileptics may be used to manage trigeminal neuralgia? a. Phenytoin b. Carbamazepine c. Ethosuximide d. Valproic acid

ANS: B Carbamazepine is used to treat trigeminal neuralgia and atypical facial pain. Phenytoin has been used to treat neurologic pain. Ethosuximide is used to treat absence seizures. Valproic acid has been used for prophylaxis for migraine headaches.

Which is the most important drug interaction of antiepileptic drugs? a. Precipitation of hypertensive crisis b. Stimulation of hepatic microsomal enzymes c. Allergenicity d. Central nervous system depression

ANS: B Inducing these enzymes results in a reduction in the blood level of the affected drugs. Precipitation of hypertensive crisis or allergenicity is not associated with antiepileptic drugs. Additive central nervous system depression is associated with these drugs so additional CNS depressants should be used cautiously; however, CNS depression is not the most important drug interaction.

The mechanism of action of vigabatrin is thought to be a. inhibition of voltage-gated sodium channels. b. irreversible inhibition of GABA. c. as an antagonist to glycine. d. stabilization of neuronal membranes.

ANS: B It is believed to be the result of irreversible GABA inhibition. Eslicarbazepine is thought to inhibit voltage-gated sodium channels. Felbamate is thought to function as an antagonist to glycine. Fosphenytoin stabilizes neuronal membranes.

Lamotrigine (Lamictal) belongs to which of the following classes of antiepileptic drugs? a. Inhibitor of uptake of GABA b. Inactivates sodium channels c. Stabilizes neuronal membranes d. Antagonist to glycine e. Unknown mechanism of action

ANS: B Lamotrigine belongs to the class of sodium channel blocking antiepileptic drugs. Lamotrigine appears to be as effective as carbamazepine and better tolerated in elderly patients newly diagnosed with partial or generalized seizures. Tiagabine (Gabitril) is an inhibitor of GABA uptake. Fosphenytoin (Cerebyx) stabilizes neuronal membranes. Felbamate (Felbatol) is an antagonist to glycine. Levetiracetam (Keppra) and oxcarbazepine (Trileptal) have an unknown mechanism of action.

Which antiepileptic medication has been known to produce osteomalacia? a. Carbamazepine b. Phenytoin c. Ethosuximide d. Gabapentin e. Lamotrigine

ANS: B Phenytoin interferes with the metabolism of vitamin D to its active form. In addition, it increases vitamin K metabolism, which is also important for proper bone formation (osteocalcin is a vitamin K-dependent protein). Carbamazepine, ethosuximide, gabapentin, and lamotrigine are not documented to produce osteomalacia.

Surgical intervention to reduce phenytoin-induced gingival enlargement should wait until at least 18 months after cessation of therapy because a. the drug remains in circulation for at least 2 years. b. some patients experience additional reduction in the enlargement after the 1-year period. c. excessive sclerosis will result from earlier intervention. d. treating the situation earlier than that will lead to excessive hemorrhage.

ANS: B Some patients experience additional reduction in the enlargement after the 1-year period. The other choices are not the reason why surgical intervention to reduce phenytoin-induced gingival enlargement is delayed for 18 months following cessation of therapy.

Ethosuximide is the drug of choice for the treatment of _____ seizures. a. generalized tonic-clonic b. generalized absence c. partial simple d. partial complex

ANS: B The drug of choice for the treatment of absence seizures is ethosuximide. Its mechanism of action may involve inhibiting the T-type calcium channels. Ethosuximide is ineffective in partial seizures with complex symptoms or in tonic-clonic seizures.

Alopecia may be observed as an adverse effect of phenytoin. Carbamazepine can cause hirsutism. a. Both statements are true. b. Both statements are false. c. The first statement is true, the second is false. d. The first statement is false, the second is true.

ANS: B The opposite is the case: phenytoin can cause hirsutism, and carbamazepine can cause alopecia. Skin reactions to phenytoin range from rash to exfoliative dermatitis, lupus erythematosus, or Stevens-Johnson syndrome. Some patients experience hypertrichosis or hirsutism on the trunk and face. Carbamazepine can cause rashes, urticarial, photosensitivity reactions, and altered skin pigmentation. Erythema multiforme, erythema nodosum, and aggravation of systemic luTpuEsSeTryBthAemNKatSosEuLs hLaEvRe .beCeOn Mreported. Alopecia can also occur.

A patient experiencing tonic-clonic seizures should be managed by a. lowering the patient's head in the dental chair until it is even with the heart. b. tilting the patient's head to one side to prevent aspiration. c. placing a tongue blade or a pencil between the patient's teeth. d. having the patient place his or her head between the knees.

ANS: B The patient's head should be tilted to one side to prevent aspiration. Management of the patient experiencing tonic-clonic seizures should include moving the patient to the floor if possible, tilting the head to one side, and removing objects from the patient's mouth before the seizure to prevent fracturing teeth.

Which of the following drugs is often used first for treating patients with generalized tonic-clonic seizures even though it is not Food and Drug Administration (FDA) approved for this use? a. Lamotrigine b. Valproate c. Levetiracetam d. Oxcarbazepine

ANS: B Though not FDA approvedT, EvaSlpTrBoaAteNiKs SofEteLnLuEseRd.fiCrsOt Min treating those patients with generalized tonic-clonic seizures based upon the results presented in the medical literature. Valproate is FDA approved for migraine prophylaxis and bipolar disorder. Lamotrigine is indicated for adjunct therapy in patients ≥2 years of age with partial seizures, primary generalized tonic-clonic seizures or generalized seizures of the Lennox-Gastaut syndrome. Levetiracetam is indicated for adjunct therapy for adults and children ≥1 month old with partial seizures, adults and children ≥6 years of age with primary generalized tonic-clonic seizures, adults and adolescents ≥12 years old with myoclonic seizures. Oxcarbazepine is indicated for monotherapy and adjunct therapy for partial seizures in adults and children ≥4 years of age and adjunctive therapy for children ≥2 years of age.

Which of the following statements is true regarding adverse reactions to antiepileptic agents? a. These medications have a broad therapeutic index. b. CNS depression is a common side effect of antiepileptic agents. c. Central nervous system (CNS) depression will antagonize that of other sedative agents. d. Both A and B are true. e. Both B and C are true.

ANS: B Tolerance develops to the CNS effects while the antiepileptic effect persists. Impaired learning and cognitive abilities occur in some patients. Another CNS side effect is exacerbation of a seizure type that is not being treated. The antiepileptics have a narrow therapeutic index; therefore, the dose must be carefully titrated to obtain the desired blood levels. CNS depression is additive with other CNS depressants such as the opioids.

Which drugs are indicated as first choice drugs for both generalized and partial seizures? (Select all that apply.) a. Carbamazepine b. Levetiracetam c. Lamotrigine d. Oxcarbazepine e. Ethosuximide

ANS: B, C Levetiracetam and lamotrigine are drugs of first choice for tonic-clonic, atypical absence, atonic, and myoclonic generalized seizures, and for all types of partial seizures. Carbamazepine and oxcarbazepine are drugs of first choice for partial seizures; however, they are not drugs of first choice for generalized seizures. Ethosuximide is indicated as a first choice for absence generalized seizures.

Which agent has a narrow therapeutic index because its metabolism is a saturable process? a. Gabapentin b. Phenobarbital c. Phenytoin d. Valproic acid e. Clonazepam

ANS: C At doses near the therapeutic range, phenytoin can be metabolized by a zero-order kinetic process, meaning that drug metabolism cannot keep up with the level of drug in the body. Drug levels can rise precipitously as a consequence and cause life-threatening toxicity. Phenobarbital, valproic acid, and clonazepam are metabolized in a nonsaturable (first-order kinetic) manner at doses near the therapeutic range. Gabapentin is not metabolized.

Clonazepam (Klonopin) is a. a chemical analogue carbamazepine. b. used parenterally to treat status epilepticus. c. used as an adjunct to treat ethosuximide-resistant absence seizures. d. not effective in akinetic seizures. e. an inhibitor of sodium channels.

ANS: C Clonazepam is effective alone or as an adjunct in the treatment of petit mal seizures. Clonazepam is a benzodiazepine, whereas carbamazepine is a chemical analogue of tricyclic antidepressants and phenothiazines. Clonazepam is not used parenterally. Clonazepam, as with other benzodiazepines, has activity against a wide variety of seizures, including akinetic seizures. The benzodiazepines do not inhibit sodium channels. They bind to the GABA receptor complex and facilitate the entry of chloride into postsynaptic nerve terminals.

Each of following is considered a drug of choice for treatment of generalized tonic-clonic seizures except one. Which is the exception? a. Levetiracetam b. Valproate c. Eslicarbazepine d. Lamotrigine

ANS: C Eslicarbazepine (Aptiom) is used as monotherapy and adjunctive therapy for partial-onset seizures. Valproate, lamotrigine, and levetiracetam are considered the drugs of choice for treatment of generalized tonic-clonic seizures.

Fetal hydantoin syndrome is associated with maternal ingestion of a. carbamazepine. b. phenobarbital. c. phenytoin. d. gabapentin.

ANS: C Fetal hydantoin syndrome is the term given to the congenital abnormality associated with maternal ingestion of phenytoin. It includes craniofacial abnormalities, microcephaly, nail or digit hypoplasia, limb defects, growth deficiency, and mental retardation. The other drugs are not associated with fetal hydantoin syndrome.

Gingival enlargement may occur in what percentage of chronic users of phenytoin? a. 10% b. 30% c. 50% d. 90% e. None of the above

ANS: C Gingival enlargement occurs in approximately 50% of all chronic users. In approximately 30% of affected patients, gingival enlargement is severe enough to require surgical intervention. The remaining choices do not represent the percentage of gingival enlargement found in chronic users of phenytoin.

Each of the following is an example of a type of generalized seizure except one. Which is the exception? a. Tonic-clonic b. Myoclonic c. Simple d. Akinetic e. Absence

ANS: C Partial seizures include: simple, complex, secondarily generalized, and temporal lobe. Tonic-clonic, myoclonic, akinetic, and absence are all types of generalized seizures.

Seizures characterized by a duration for longer than 30 minutes are called _____ seizures. a. akinetic b. complex c. status epilepticus d. myoclonic e. simple (Jacksonian)

ANS: C Status epilepticus seizures are an emergency situation, especially if hypoxia has occurred. Parenteral benzodiazepines, such as diazepam (Valium), are the drugs of choice to control this type of seizure. Tonic-clonic, myoclonic, akinetic, and absence seizures are not defined as seizures of long duration. Status epilepticus seizures are continuous tonic-clonic seizures that last longer than 30 minutes or recur before the end of the postictal period of the previous seizure.

Which of the following statements is true concerning epilepsy? a. Epileptic seizures can be recorded on electrocardiogram. b. Seizure activities are estimated to affect approximately 10% of the population. c. The majority of epileptic patients have idiopathic epilepsy. d. The most common generalized seizures are temporal lobe (psychomotor).

ANS: C The majority of epileptic patients have idiopathic epilepsy, meaning an unknown cause. Epileptic seizures are recorded on an electroencephalogram (EEG) rather than electrocardiogram. Seizure disorders are estimated to affect 1% of the population; therefore, the dental team will likely encounter a patient with epilepsy. Temporal lobe seizures are partial rather than generalized seizures.

Valproate is associated with toxicity of which of the following organs? a. Heart b. Kidney c. Liver d. Pancreas

ANS: C Valproate is associated with hepatotoxicity. Dose-related changes in liver enzymes often occur in these patients. Deaths caused by hepatic failure have also been reported. Because valproic acid can produce serious hepatotoxicity, hepatic function tests should be performed. Signs of hepatotoxicity include nausea, vomiting, abdominal pain, loss of appetite, and diarrhea. One of the other choices represents the idiosyncratic toxicity of valproate.

Which of the following seizures are categorized as generalized seizures? a. Absence seizures b. Simple (Jacksonian) seizures c. Tonic-clonic seizures d. Both A and C E. Both B and C

ANS: D Absence seizures and tonic-clonic seizures are considered to be generalized seizures. Consciousness is lost in both types. Whereas little movement occurs in absence seizures, major movement of large muscle groups occurs in tonic-clonic seizures. Simple (Jacksonian) seizures are considered partial seizures. Partial epilepsies involve activation of only part of the brain, and the location of the activity determines the clinical manifestation. The attack is called a simple partial attack when consciousness is not impaired. The attack is called a complex partial attack when consciousness is impaired.

Which of the following agents interferes with platelets? a. Carbamazepine b. Valproic acid c. Ethosuximide d. Both A and B e. Both A and C

ANS: D Carbamazepine and valproic acid can cause thrombocytopenia, a decrease in platelet count. In addition, valproic acid inhibits the second phase of platelet aggregation. Ethosuximide may cause agranulocytosis but does not commonly affect platelets or platelet formation.

The drug of choice for treatment of absence seizures is a. brivaracetam. b. eslicarbazepine. c. vigabatrin. d. ethosuximide.

ANS: D Ethosuximide is the drug of choice in the treatment of typical absence seizures. Brivaracetam is used for partial seizures in patients 16 years of age and older. Eslicarbazepine is used for partial-onset seizures in adults. Lacosamide is used for adults with partial onset seizures. Vigabatrin is used for infantile spasms and as adjunctive therapy for complex partial seizures refractory to other antiepileptic drugs (AEDs) in persons 10 years of age and older.

Which antiepileptic agent is commonly prescribed for trigeminal neuralgia? a. Lamotrigine b. Phenytoin c. Gabapentin d. Carbamazepine e. Valproic acid

ANS: D One of the primary uses of carbamazepine is for the treatment of trigeminal neuralgia. It is also indicated in the treatment of bipolar depression. Lamotrigine and gabapentin are not used for pain alleviation. Phenytoin and valproic acid are used but not (or not commonly) for trigeminal neuralgia.

_____ is noted for having cross-sensitivity with carbamazepine in 20% to 30% of patients. a. Lamotrigine b. Valproate c. Levetiracetam D. Oxcarbazepine

ANS: D Oxcarbazepine is chemically similar to carbamazepine but causes less induction of hepatic enzymes and it does not induce its own metabolism. Cross-sensitivity with carbamazepine occurs in 20% to 30% of patients. Carbamazepine can reduce lamotrigine levels while valproate increases lamotrigine levels more than twofold. No clinically significant drug-drug interactions have been reported with levetiracetam.

The cause of phenytoin gingival enlargement is a. inhibition of fibroblast activity. b. accumulation of hemosiderin. c. alteration of chemotaxis. d. unknown.

ANS: D The cause is unknown. Many causes have been investigated, including alteration in the function of the adrenal gland, hypersensitivity or allergic reaction, immunologic reaction, and vitamin C or folate deficiency. None of the other choices are regarded as contributing to phenytoin gingival enlargement.

Each of the following statements is true of absence seizures except one. Which is the exception? a. Seizures last a few seconds. b. No loss of body tone occurs. c. The patient is usually unaware that the seizure is happening. d. A drug of choice for treatment is ethosuximide. e. To avoid trauma, tongue blades should not be used in the oral cavity.

ANS: E Unlike tonic-clonic seizures, no uncontrolled motor activity occurs in absence seizures. Consequently, no risk exists in using tongue blades in these patients. The other choices are accurate characteristics of absence seizures. The symptoms include a brief loss of consciousness. Body tone is not lost and the patient is usually unaware the seizures are occurring. The drug of choice is either ethosuximide or valproate. Lamotrigine is an effective alternative.

Vitamin C is an effective adjunctive therapy for gingival enlargement.

ANS: False Although vitamin C has been tried in the treatment of gingival enlargement, it has not been shown to be effective in controlled trials.

T/F Lamotrigine is an effective treatment for myoclonic seizures.

ANS: True Lamotrigine is indicated for atypical absence, atonic, or myoclonic generalized seizures.

T/F The better the patient's oral hygiene is, the less likely that lesions associated with use of phenytoin will occur.

ANS: True The better the patient's oral hygiene, the less likely the lesions are to occur or the less severe they will be if they do occur.