Epilepsy Pharmacology Flashcards
what are the four key mechanisms for AEDS?
reduce electrical excitability of cell membranes
enhance GABA mediated synaptic inhibition
inhibition of calcium channels
unknown mechanisms
name six sodium channel blockers
phenytoin carbamazapine oxcarbazepine lamotragine ezcarbazine lacosamide
name potassium channel opener
retigabine
give four examples of GABAa acting drugs
Barbiturates
Tiagabine
Vigabatrin
Benzodiazepines
what are the four types of calcium channel acting drugs
T type (Ethosuxamide, Zonisamide)
L TYPE (barbiturates, felbamate)
N type (Lamotragine, barbiturates, oxcarbazepine)
P/Q type (Lamotragine, oxcarbazepine)
give an example of an AED that acts on glutamate
parampenel
the decision to treat first seizure is controversial because the risk of recurrent seizures on average is…
30-30% in 2 yrs
24% with normal EEG and MRI
65% with lesion
under what circumstances does nice (2004/2012) recommend treating after a first seizure?
if there is: neurological deficit,
EEG unequivocally epileptogenic.
Structural abnormality on imagine,
risk of further fit unacceptable to pt
what percent of people are seizure free after one one AED is trialed?
70%
what percent of people are seizure free after two AEs are trialed?
5 to 10% (70% with 1)
what percentage still have seizures after two AEDs are trialed?
20%
what is the procedure for AED therapy
sequential monotherapy,
Start with one AED and push dose to clinical toxicity or seizure control.
2) if seizures continue: start a second drug: titrate to adequeate dose, then remove first AED.
3) If seizures continue: repeat with a third drug. 4) if seizures continue: reconsider diagnosis, consider combination therapy.
serum AED monitoring can be useful to:
check for adherance,
assess dose related side effects,
to guide phenytoin/phenobarbital treatment
what are some reasons for poor compliance?
poor communication, poor memory, poor understanding of instructions, mis-information, side effects, poor dose regimens, difficulty swallowing/poor taste
what two drugs are most useful for the treatment of focal epilepsy?
carbamazepine (tegeratol)
lamotragine (lamictal)
name 5 drugs most useful for treatment of idiopathic generalised epilepsy
sodium valporate, lamotrigine, levitacetam, ethosuxamide, phenytoin
treatment choice of AED for patial epilepsy depends largely on
side effect profile and patient’s preference/concerns
choice of AED for generalised epilepsy depends on
predominant seizure type as well as side effects and preference
what does NICE recommend as first line treatment for focal seizures, and what adjunctives?
carbamazepine OR lamotragine,
add ons: clobazam, gabepentin, topiramate,
what does NICE recommend as first line treatment for newly diagnosed generalised tonic clonic seizures?
sodium valporate
(others: lamotrigine, carbamazepine, oxcarbazepine)
add ons: clobazam, levetiracetam, topiramate
what first line treatments does NICE reccoemend for absense seizures and what should be avoided?
ethosuxamide OR sodium valporate
(add ons: clobaam, clonazepam, levetiracetam, topirimiate, zonisamide,)
AVOID: carbamazepine, oxcarbazepine, phenytoin, pregabalin.
what does NICE 2012 recommend for first line treatment of myoclonic seizures
sodium valporate,
(add ons clobazepam, clonazepam, piracetam, zonisamide)
AVOID : carbamazepine, gapapentin, oxcarbazine, phenytoin, pregablin, tiagabine, vigabrtin.
what dos NICE 2012 recommend as first line treatment for tonic/atonic seizures?
lamotragine
(add ons: rufinamide, topiramate)
AVOID: carbamazepine, gabapentin, oxcarbazepine, pregablin, tiagabine, vigabatrin
what AEDs can induce metabolism of other drugs?
carbamazepine,
phenytoin,
phenobarbitol,
primidone
