Mod 3 Antiepileptic Drugs Flashcards
Epilepsy
Seizure
Brief episode of abnormal electrical activity in the nerve cells of the brain
Convulsion
Involuntary spasmodic contractions of any or all voluntary
muscles throughout the body, including skeletal and facial
muscles
Epilepsy
Chronic, recurrent pattern of seizures
Primary (idiopathic)
Cause cannot be determined
More than 50% of epilepsy cases
Secondary
Distinct cause identified
• Trauma, infection, cerebrovascular disorder
Classification of Epilepsy
Partial-onset seizures Simple (formerly known as petit mal seizures) Complex Secondary generalized tonic-clonic Generalized-onset seizures Formerly known as grand mal seizures Unclassified seizures Status epilepticus
Antiepileptic Drugs
Also known as anticonvulsants Goals of therapy To control or prevent seizures while maintaining a reasonable quality of life To minimize adverse effects and drug-induced toxicity AED therapy is usually lifelong Combination of drugs may be used Single-drug therapy started before multiple-drug therapy is tried Serum drug concentrations must be measured Therapeutic drug monitoring Patients who are seizure free for 1 to 2 yearsmay be able to discontinue antiepileptic therapy
Mechanism of Action
AED therapy must:
Prevent generation and spread of excessive
electrical discharge from abnormally functioning nerve cells
Protect surrounding normal cells
AEDs thought to alter movement of sodium,
potassium, calcium or magnesium ions across nerve cells in the brain
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
Mechanism of Action (cont’d)
Overall effect
Neurons are stabilized
Neuron hyperexcitability is decreased
Spread of excessive nerve impulses is decreased
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 often necessitate a change in
medication Black box warning as of Suicidal thoughts and behavior
Long-term therapy with phenytoin may cause gingival hyperplasia, acne, hirsutism, and Dilantin facies
Antiepileptic Drugs (cont’d)
phenobarbital (Solfoton) primidone carbamazepine (Tegretol) valproic acid (Depakote) phenytoin (Dilantin) fosphenytoin succinimides, such as ethosuximide (Zarontin) benzodiazepines (clonazepam and clorazepate) gabapentin (Neurontin) lamotrigine (Lamictal) pregabalin (Lyrica) levetiracetam (Keppra) topiramate (Topamax) tiagabine (Gabitril)