Antiepileptic Drugs Flashcards
what are seizures
the clinical expression of abnormal, hyper synchronous brain activity
- manifestations reflect the function of the brain area involved
- may include impairment of cognition or consciousness, involuntary movements, behavioural automatisms, and sensory, psychic or autonomic functions
what are epilepsies and epileptic syndromes
- spontaneous recurrent seizures
- characterized by a clustering of signs and symptoms that regularly occur together
seizure classification
- partial seizures (focal): simple and complex partial
2. partial seizures evolving to secondarily generalized seizures
pathophysiology
- focal epileptogenesis
- synchronization
- propagation
actions of anti epileptic drugs
- voltage and frequency dependent blockade of Na channels; slow recovery from inactivation; blockade of sustained, high-frequency AP
- potential GABA-mediated neuronal inhibition
- inhibit low threshold, Ca++ (T) currents in thalamic neurone
- inhibit excitatory a.a neurotransmitter release
- inhibit glutamate NMDA receptor
when does therapy begin
after 2 or more seizures
how do you monitor the effectiveness of the drugs
monitor plasma concetrations
what drugs are used to treat status epilepticus
- Lorazepam or diazepam IV
- phenytoin or phenobarbital
- phenobarital or phenytoin
- anesthetic
what are CNS AE
- sedation
- dizziness, blurred vision, diplopia
- cerebellar and brainstem dysfunction
- extrapyramidal dysfunction
- cognitive impairment
*dose-related CNS effects limit the dosage of most AEDs
what are dermatologic AE
-rashes ranging from mild to life-threatening
what are hematologic AE
-rxns secondary to altered folate metabolsim; coagulation defects; immune-mediated phenomena; bone marrow suppression
other AE
- hepatic (idiosyncratic)
- renal
- MSK
- decrease in bone mineral content
- CT disorders
- endocrine
- teratogenicity
- increase risk of suicidal thoughts and behaviours
AEDs (phenytoin, carbamazepine, phenobarbital, primidone) induce what
P-450 enzymes
what effect does valproate have on AEDs
inhibits metabolism of phenytoin, Iamotrigine, and carbamazepine
what effects do antimicrobials have on AEDs
macrolide Abs and azole antifunals may cause elevated levels of certain AEDs (carbamazepine, phenytoin, valproate, zonisamide)
