Chapter 14 Antiepileptic Drugs Flashcards
Seizure
Brief episode of abnormal electrical activity in nerve cells of the brain
Convulsion
Involuntary spasmodic contractions of any or all voluntary muscles throughout the body, including skeletal, facial, and ocular muscles
Epilepsy
Chronic, recurrent pattern of seizures
Primary (idiopathic) Epilepsy
Cause cannot be determined
Roughly 50% of epilepsy cases
Secondary (symptomatic) Epilepsy
-Distinct cause is identified
Trauma, infection, cerebrovascular disorder
Generalized onset seizures
- Formerly known as grand mal seizures
- Tonic-clonic seizures
- Absence seizures
Partial onset seizures
- Simple (formerly known as petit mal seizures)
- Complex
- Secondary generalized tonic-clonic
Status Epilepticus
- Multiple seizures occur with no recovery between them
- Result: hypotension, hypoxia, brain damage, and death
- True medical emergency
Goals of therapy for Antiepileptic Drugs (AEDs)
- To control or prevent seizures while maintaining a reasonable quality of life
- To minimize adverse effects and drug-induced toxicity
Antiepileptic drugs traditionally used to manage seizure disorders include:
- Barbiturates
- Hydantoins
- Iminostilbenes plus valproic acid
- Second- and third-generation antiepileptics
Pharmacologic effects of Antiepileptic drugs
- Reduce nerve’s ability to be stimulated
- Suppress transmission of impulses from one nerve to the next
- Decrease speed of nerve impulse conduction within a neuron
Antiepileptic Drugs: Indications
- Prevention or control of seizure activity
- Long-term maintenance therapy for chronic, recurring seizures
- Acute treatment of convulsions and status epilepticus
Antiepileptic Drugs: Adverse Effects
-Numerous adverse effects; vary per drug
-Adverse effects often necessitate a change in medication
-Black box warning as of 2008
Suicidal thoughts and behavior
-Long-term therapy with phenytoin (Dilantin) may cause gingival hyperplasia, acne, hirsutism, and Dilantin facies.
Primidone is metabolized in the liver to:
phenobarbital
Most common adverse effect of Phenobarbital and Primidone (Mysoline)
sedation
Barbiturates: Phenobarbital and Primidone (Mysoline): Contraindications
known drug allergy, porphyria, liver or kidney impairment, and respiratory illness
Barbiturates: Phenobarbital and Primidone (Mysoline):
Adverse effects
cardiovascular, CNS, gastrointestinal (GI), and dermatologic reactions
Hydantoins: Phenytoin
Adverse Effects
gingival hyperplasia, acne, hirsutism, Dilantin facies, and osteoporosis
Carbamazepine (Tegretol)
- Second most commonly prescribed antiepileptic drug in the United States after phenytoin
- Autoinduction of hepatic enzymes
Oxcarbazepine (Trileptal)
- Chemical analogue of carbamazepine
- Precise mechanism of action has not been identified
Ethosuximide (Zarontin)
- Used in the treatment of uncomplicated absence seizures
- Not effective for secondary generalized tonic-clonic seizures
- Contraindication: known allergy
- Adverse effects: GI and CNS effects
- Drug interactions: hepatic enzyme–inducing drugs
Gabapentin (Neurontin)
- Chemical analogue of GABA, a neurotransmitter that inhibits brain activity
- Believed to work by increasing the synthesis and synaptic accumulation of GABA between neurons
- Contraindication: known drug allergy
- Adverse effects: CNS and GI symptoms
Lamotrigine (Lamictal)
- Also used for the treatment of bipolar disorder
- Contraindications: drug allergy
- Common adverse effects: relatively minor CNS and GI symptoms and possible Stevens-Johnson syndrome
Levetiracetam (Keppra)
- Adjunct therapy for partial seizures with and without secondary generalization
- Contraindication: known drug allergy
- Mechanism of action: unknown
- Adverse effects: generally well tolerated, CNS
- No drug interactions
