Anti Epileptic Drugs Flashcards
What are anti epileptic drugs?
Drugs which
Provide symptomatic relief
In people with epilepsy
Decrease the frequency
And / or
The severity
Of seizures
What are the goals of anti epilepsy treatment?
Maximum seizure control
Maximum quality of life
Minimum side effects
Minimum dose
Monotherapy
What are the outcomes of anti epilepsy therapy?
60% fully seizure free
20% drastically reduced
20% refractory
How are anti epilepsy drugs classified?
Classical (before 1975)
New (after 1975)
Mechanism wise
SINGLE
MULTIPLE (valproate, new)
What are the classic AEDs?
Phenytoin (hydantoins)
Phenobarbital (barbiturate)
Primidone (deoxybarbiturate)
Carbamazepine (iminostilbene)
Ethosuximide (succinamide)
Valproate (aliphatic carboxylic acid)
Clonazepam (benzodiazepines)
What are the new AEDs?
Lamotrigine (phenyltriazine)
Gabapentin (GABA analogue)
Topiramate
Felbamate
Vigabatrin
Tiagabine
Levetiracetam
Fosphenytoin
What is the general mechanism of action of AED?
Normal CNS function
Excitatory glutamate
Inhibitory GABA
In balance
In epilepsy
More excitatory glutamate
Less inhibitory GABA
AEDs reduce glutamate and/or increase GABA
To inhibit neuronal discharge
Or spread of discharge
Have a use dependent blocking of ion channels
Therefore selective to seizure focus
What are the types of mechanism of action of AEDs?
Sodium channel blockers
Voltage and frequency dependent block in refractory inactive phase
Transient “T” Calcium channel blockers
GABA receptor agonist
What are the sodium channel blocker AEDs?
Carbamazepine
Phenytoin
Lamotrigine
Valproate
What are the calcium channel blocker AEDs?
Ethosuximide
Gabapentin
Pregabalin
Valproate
What are the GABA agonists?
Valproate
Barbiturates
Benzodiazepines
Vigabatrin
Gabapentin
What are the first line AEDs?
GTCS
Carbamazepine
Lamotrigine
Valproate
ABSENCE
Ethosuximide
Lamotrigine
Valproate
FOCAL
Carbamazepine
Lamotrigine
Valproate
How do you choose an AED?
Epilepsy type
PK profile
Interactions
Comorbidities
Efficacy
Adverse effects
Cost
What are the principles of AED therapy?
When to start (high risk of recurrence)
Which drug
Monotherapy unless ineffective at maximum tolerated dose for 3 months
What dose (start 1/3rd of final)
What dosing regimen (half life, frequency, compliance)
When to switch to other monotherapy
Duration of therapy
How to withdraw
Advice to the patient
What are the important AED facts for specific populations?
Nenonates - low dose
Children - high dose more frequently
Elderly - low dose
Pregnancy - low dose carbamazepine
Breastfeeding - precautions
Reproductive age - OCP failure
