Antiepileptic Drugs Flashcards
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 a convulsion?
Involuntary spasmodic contractions of any or all voluntary muscles throughout the body, including skeletal, facial, and ocular muscles
What is epilepsy?
Chronic, recurrent patterns of seizures
What is primary epilepsy and what is it AKA?
Idiopathic
Cause cannot be determined, roughly 50% if epilepsy cases
What is secondary epilepsy and what is it AKA?
Symptomatic
Distinct cause is identified
What are the 2 classifications of epilepsy excluding unclassified seizures?
Generalized onset seizures
Both hemispheres, tonic-clonic seizures, atonic seizures AKA drop attacks
Focal Onset seizures
Localized or focal region, simple complex, secondary generalized tonic-clonic
What is the drug of choice for immediate treatment of status epilepticus?
Diazepam
What are the goals of therapy for antiepileptic drugs?
Controlling or preventing seizures while maintaining a reasonable quality of life
Titrate to lowest possible dose that controls seizures
T/F: Antiepileptic drug therapy is short term
False; It is usually lifelong
T/F: Multiple drug therapy is started before single-drug therapy is tried
False: Single-drug therapy is started before Multiple-drug therapy is tried
Serum concentrations of _____, _______, ________, and ________ correlate better with seizure control and toxicity than _________, ________, and ________.
Phenytoin, phenobarbital, carbamazepine, primidone
Valproic acid, ethosuximide, and clonazepam
What are the 4 classes of antiepileptic drugs?
Barbiturates
Hydantoins
Iminostilbenes plus valproic acid
2nd and 3rd gen antiepileptics
What are the drug 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
What are the indications of antiepileptic drugs?
Prevention or control of seizure activity
Long-term maintenance therapy for chronic seizures
Acute treatment of convulsions and status epilepticus
What can long term therapy of phenytoin cause?
Gingival hyperplasia, acne, hirsutism and dilantin facies
What are the contraindications of AEDs?
Pregnancy
What are the interactions of AEDs?
Phenytoin: Antibiotics, antifunfals, SSRI’s reduce clearance and increase toxicity, warfarin
Carbamazepine: Increased metabolism of acetaminophen resulting in reduced efficacy
Valproic acid: Asprin displaces it from protein binding resulting in increased levels and toxicity risk
What 4 drugs have a narrow therapeutic index and require lab drug monitoring?
Phenytoin, valproic acid, phenobarbital, carbamazepine
What is phenobarbital and primidone? (AE, CI, TE)
AE: Sedation
CI: Porphyria, liver or kidney impairment, respiratory illness
TE: 15 - 40 mcg/mL
What are the therapeutic levels of phenytoin?
10 - 20 mcg/mL
What are some considerations regarding IV admin of phenytoin?
20 gauge or larger venous catheters
Diluted in NS
Filter must be used
What is the second most commonly prescribed AED in canada after phenytoin?
Carbamazepine
What is Ethosuximide? (ID, CI, AE, IE)
ID: Uncomplicated absence seizures
CI: Allergy
AE: GI and CNS effects
IE: Hepatic enzyme-inducing drugs
What is Lamotrigine?(ID, CI, AE, Forms)
ID: Bipolar disorder
CI: Allergy
AE: Minor CNS and GI symptoms and possible Stevens-Johnson syndrome
Oral use only
