Anticonvulsants Flashcards
Epilepsy
disorder of brain function characterized by periodic and unpredictable seizures
Seizure
alteration of behaviors due to excessive firing of brain neurons
Partial/ Focal Seizure
neuron firing is localized to cerebral cortex
normally just one hemisphere
Generalized Seizure
widespread neuron firing
both hemispheres
Difference between Simple and Complex Partial Seizures
simple- consciousness preserved
complex- impaired consciousness
Tonic- Clonic Seizures
tonic phase- loss of consciousness, muscle rigidity, respiratory arrest
clonic phase- muscle jerking, lip/ tongue biting, urinary/ fecal incontinence
Absence Seizures
sudden onset and abrupt ending
impaired consciousness
stop around age 20
Myoclonic Seizures
single or multiple myoclonic muscle jerks
no loss of consciousness
can happen many times in a day
Pathophysiology of Epilepsy
hyperexcitable neurons fire abnormally and inhibitory (GABAa) synaptic currents break down to cause seizures
Examples of Na Channel Modulators that enhance fast action
phenytoin
carbamazepine
valproate
MOA of Na Channel Modulators that enhance fast inactivation
decrease Na influx, prolongs inactive state of neurons
Phenytoin
IV only
1st order, 2nd at high doses
increases metabolism of other drugs- bad mix w/ contraceptives
SE of Phenytoin
gingival hyperplasia
decreased bone density from increased Vit D metabolism
coarsening facial features
Active Metabolite of Carbamazepine
10, 11 epoxide
SE of Carbamazepine
blurred vision
stupor, coma, respiratory depression
Valproate
covers all types of seizures
MOA of Valproate
increases inactivated sodium channels at different sites than phenytoin and carbamazepine
reduces Ca currents in thalamic neurons
increases GABA
SE of Valproate
elevated hepatic enzymes- hepatitis
Examples of Na channel modulaters that enhance slow inactivation
Lacosamide
Lacosimide SE
double vision
suicidal thoughts
MoA of Ethosuximide
reduces Ca currents in thalamic neurons to inhibit absence seizures
SE of Ethosuximide
nausea, vomiting, anorexia
photophobia
Gabapentin MOA
GABA agonist by binding to a2sig of Ca channel, decreasing Ca entry
SE of Gabapentin
none
Diazepam MOA
act on GABA receptors and increase frequency of opening of GABA activated Cl channels
Use of Clonazepam
absence and myoclonic seizures in children
Use of Diazepam
status epilepticus
MOA of Phenobarbital
increases duration of GABA receptor Cl channels
SE of Phenobarbital
Morbilliform rash
MOA of Perampanel
antagonist of AMPA glutamate receptor- prevents neuronal firing
Pharmacokinetics of Perampanel
metabolized by hepatic CYP3A
decreases effectiveness of contraceptives, carbamazepine
SE of Peramapanel
anxiety, double vision
Drugs for Focal/ Partial Seizures
carbamazepine
phenytoin
Drugs for Tonic- Clonic Seizures
carbamazepine
phenytoin
valproic acid
Drugs for Absence Seizures
Ethosuximide
Drug for Myoclonic Seizures
Valproic Acid
Drug for Status Epilepticus
Diazepam