Anticonvulsants Flashcards
What is epilepsy?
Chronic disorder characterized by recurrent seizures
What is the cause of primary epilepsy?
cause unknown
What is the goal of management for epilepsy?
Restoration of a normal pattern of activity
What are the two broad categories of seizures?
Partial
generalized
What are partial seizures?
Seizures that remain localized to one area of the brain, without LOC
Complex partial seizures usually start where in the brain? SSx?
Temporal lobe
Lip smacking, fumbling, scratching (no memory of events)
What are generalized seizures?
Abnormal electrical activity throughout the brain
What are tonic-clonic seizures?
LOC, with tonic spasms, followed by maximal tonic spasms
What is the tonic phase of a seizures?
Rigidity of all limbs, followed by a tremor that is actually an interruption of the tonis by relaxation
What is the clonic phase of a seizure?
Massive jerking of the body that slows over 0-120 seconds, usually leaving pt in a stuporous state
What is the physiological basis for seizures?
Abnormally excessive, synchronous, and rhythmic firing of hyperexcitable neurons
What are the four underlying causes of seizure development?
- CNS injury
- Congenital abnormality (birth trauma)
- Genetic factors
- Infections
What is the major genetic factor associated with seizures?
Defective genes coding for voltage gated ion channels, or GABA receptors
What are the ssx of complex partial seizures?
Impaired consciousness, dreamy disaffective state, and wwo automatisms
What are the ssx of absence (petit mal) seizures?
Impaired consciousness with staring spells, wwo eyeblink
Who usually has absence seizures? Prognosis?
Children, and is self-limiting
What are the characteristics of complex partial seizures?
Automatisms with affected consciousness
What are the four stages of generalized seizures?
- Aura
- Tonic phase
- Clonic phase
- Stuporous state and sleep
What are tonic seizures?
LOC with severe hypertonic spasms and autonomic effects
What are atonic seizures?
Sudden LOC with rhythmic clonic contractions, and autonomic effects
What are infantile spasms?
Recurrent myoclonic jerks of the body with sudden flexion or extension of the body and limbs
What is status epilepticus?
Continuous or very rapid recurring seizures, usually of the tonic-clonic type
What are the three stages of seizures development?
- Initiation
- Synchronization of surrounding
- Propagation
What are the three main EPSPs in the CNS?
Na influx
Ca current
Paroxysmal depolarization
What are the four main IPSPs in the CNS?
K efflux
Cl influx
Pumps
Low pH
What percent of patients do not respond to antiepileptics?
20%
What percent of pts can antiepileptics completely eliminate seizures?
66%
What is the surgery that can be used to treat epilepsy?
Temporal lobe resection
What is the major issue with seizures?
Poorly controlled seizures are associated with a neuronal loss mediated by an excitotoxic process
What is the role of the vagus nerve in treating seizures?
Stimulation of it can reduce seizures
What are the three major drugs used to treat partial seizures?
Carbamazepine
Phenytoin
Valproate
What are the three major drugs used to treat tonic/clonic seizures?
Carbamazepine
Phenytoin
Valproate
What are the two major drugs used to treat absence seizures?
Ethosuximide
Valproate
What are the two major drugs used to treat myoclonic seizures?
Clonazepam
Valproate
What are the four major drugs used to treat status epilepticus?
Diazepam
Lorazepam
Phenytoin
Fosphenytoin
What are the three main MOA of anticonvulsants?
- Decrease glutamate activity
- Increase inhibitory GABA
- Alter movement of ions across membrane (Ca)
What is the MOA of phenytoin?
Inactivation of VG Na channels
What is the MOA of carbamazepine?
Inactivation of VG Na channels
What is the MOA of lamotrigine?
Inactivation of VG Na and Ca channels
What is the MOA of ethosuximide?
Inactivation of VG Ca channels
What is the MOA of gabapentin?
Inactivation of VG Ca channels
What is the MOA of retigabine?
increase of K channel opening
What is the MOA of levetiracetam?
SV2A synaptic vesicle proteins
What is the MA of lacosamide?
CRMP-2