Epilepsy Pharmacology

Question 1

what are the four key mechanisms for AEDS?

Answer 1

reduce electrical excitability of cell membranes
enhance GABA mediated synaptic inhibition
inhibition of calcium channels
unknown mechanisms

Question 2

name six sodium channel blockers

Answer 2

phenytoin
carbamazapine
oxcarbazepine
lamotragine
ezcarbazine
lacosamide

Question 3

name potassium channel opener

Answer 3

retigabine

Question 4

give four examples of GABAa acting drugs

Answer 4

Barbiturates
Tiagabine
Vigabatrin
Benzodiazepines

Question 5

what are the four types of calcium channel acting drugs

Answer 5

T type (Ethosuxamide, Zonisamide)

L TYPE (barbiturates, felbamate)

N type (Lamotragine, barbiturates, oxcarbazepine)

P/Q type (Lamotragine, oxcarbazepine)

Question 6

give an example of an AED that acts on glutamate

Answer 6

parampenel

Question 7

the decision to treat first seizure is controversial because the risk of recurrent seizures on average is…

Answer 7

30-30% in 2 yrs
24% with normal EEG and MRI
65% with lesion

Question 8

under what circumstances does nice (2004/2012) recommend treating after a first seizure?

Answer 8

if there is: neurological deficit,
EEG unequivocally epileptogenic.
Structural abnormality on imagine,
risk of further fit unacceptable to pt

Question 9

what percent of people are seizure free after one one AED is trialed?

Answer 9

70%

Question 10

what percent of people are seizure free after two AEs are trialed?

Answer 10

5 to 10% (70% with 1)

Question 11

what percentage still have seizures after two AEDs are trialed?

Answer 11

20%

Question 12

what is the procedure for AED therapy

Answer 12

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.

Question 13

serum AED monitoring can be useful to:

Answer 13

check for adherance,
assess dose related side effects,
to guide phenytoin/phenobarbital treatment

Question 14

what are some reasons for poor compliance?

Answer 14

poor communication, 
poor memory, 
poor understanding of instructions, 
mis-information,
side effects, 
poor dose regimens, 
difficulty swallowing/poor taste

Question 15

what two drugs are most useful for the treatment of focal epilepsy?

Answer 15

carbamazepine (tegeratol)

lamotragine (lamictal)

Question 16

name 5 drugs most useful for treatment of idiopathic generalised epilepsy

Answer 16

sodium valporate, 
lamotrigine, 
levitacetam, 
ethosuxamide, 
phenytoin

Question 17

treatment choice of AED for patial epilepsy depends largely on

Answer 17

side effect profile and patient’s preference/concerns

Question 18

choice of AED for generalised epilepsy depends on

Answer 18

predominant seizure type as well as side effects and preference

Question 19

what does NICE recommend as first line treatment for focal seizures, and what adjunctives?

Answer 19

carbamazepine OR lamotragine,

add ons: clobazam, gabepentin, topiramate,

Question 20

what does NICE recommend as first line treatment for newly diagnosed generalised tonic clonic seizures?

Answer 20

sodium valporate

(others: lamotrigine, carbamazepine, oxcarbazepine)

add ons: clobazam, levetiracetam, topiramate

Question 21

what first line treatments does NICE reccoemend for absense seizures and what should be avoided?

Answer 21

ethosuxamide OR sodium valporate

(add ons: clobaam, clonazepam, levetiracetam, topirimiate, zonisamide,)

AVOID: carbamazepine, oxcarbazepine, phenytoin, pregabalin.

Question 22

what does NICE 2012 recommend for first line treatment of myoclonic seizures

Answer 22

sodium valporate,

(add ons clobazepam, clonazepam, piracetam, zonisamide)

AVOID : carbamazepine, gapapentin, oxcarbazine, phenytoin, pregablin, tiagabine, vigabrtin.

Question 23

what dos NICE 2012 recommend as first line treatment for tonic/atonic seizures?

Answer 23

lamotragine

(add ons: rufinamide, topiramate)

AVOID: carbamazepine, gabapentin, oxcarbazepine, pregablin, tiagabine, vigabatrin

Question 24

what AEDs can induce metabolism of other drugs?

Answer 24

carbamazepine,
phenytoin,
phenobarbitol,
primidone

Question 25

what AEDs can inhibit metabolism of other drugs?

Answer 25

valporate,

felbamate

Question 26

aspirin and warfarin can react with which drugs and alter International Normalised Ratio?

Answer 26

phenytoin, 
carbamazepine, 
Phenobarbitol, 
primidone, 
valpropic acid

Question 27

which AEDs reduce the effectiveness of the PILL:

Answer 27

CBZ, 
OXZ, 
phenobarbitol, 
phenytoin, 
primidone, 
topiramate, 
rufinamide,  
(enzyme inducing) lamotragine (Non enzyme inducing)

Question 28

which AEDs do not reduce the effectiveness of the pill

Answer 28

clonazepam, 
clobazam, 
zonisamide, 
levitiracetam, 
sodium valporate, 
vigabratrin, 
pregablin, 
gabapentin, 
ethosuxamide

Question 29

name four common adverse affects of AEDs (all AEDS)

Answer 29

diziness,
fatigue,
ataxia,
diplopia,

Question 30

name some uncommon but serious side affects of AEDS

Answer 30

renal stones, 
anhydrosis,
heat stroke, 
glaucoma, 
hyponatremia, 
hepatic failure, 
peripheral vision loss, 
rash.

Question 31

what percentage of patients experience a rash attributed to AEDs?

Answer 31

15.90%

Question 32

what types of rash can occur as a result of AEDs?

Answer 32

Stevens Johnson Syndrome,

Toxic Epidermal Necrolysis.

Question 33

when should AED withdrawal be consideres (NICE 2012),

Answer 33

after 2 yrs of seizure freedom.
Withdrawal should occur slowly, especially from benzos and barbiturates.
Withdrawal of one drug at a time.