anti epileptics

Question 1

seizure

Answer 1

“Transient abnormal electrical activity in the brain,
leading to a disturbance of consciousness, behaviour, emotion, motor function or sensation”
abnormal and excessive excitation and
synchronisation of a group of neurones within the brain

Question 2

pathology of seizures

Answer 2

glutamate + NMDA receptors: let in Na, Ca, let out K, depolarizes membrane, fires action potential
GABA: GABAa receptors: Cl channel, hyperpolarises membrane, less likely to fire AP
causes of seizures: loss of inhibitory (GABA mediated) signals
■ Or too strong an excitatory (NMDA/Glutamate

Question 3

causes of imbalance

Answer 3

genetic, exogenous activation of receptors- drugs
■ Acquired changes in brain chemistry- drug withdrawal, metabolic changes
■ Damage to any of these networks- strokes, tumours

Question 4

symptoms of seizures

Answer 4

shaking, loss of consciousness, changes in muscle tone, tongue biting,
For tonic-clonic seizures initial hypertonic phase, followed by rapid clonus (shaking/jerking) of the limbs
Post-ictal period present- can last minutes up to hours
Often an aura prior to seizure

Question 5

epilepsy

Answer 5

tendency toward recurrent seizures unprovoked by a systemic or neurological insult
two unprovoked (or reflex) seizures occurring more than 24 hours apart
epilepsy syndrome

Question 6

types of reflex seizures

Answer 6

brought on by a particular stimulus
■ Photogenic ■ Musicogenic ■ Thinking ■ Eating ■ Hot water immersion ■ Reading ■ Orgasm ■ Movement
provoked: result of another medical condition: Drug use or withdrawal ■ Alcohol withdrawal ■ Head trauma and intracranial bleeding ■ Metabolic disturbances

Question 7

classifications

Answer 7

focal: aware/impaired awareness+motor/nonmotor
generalized: loss of awareness motor/nonmotor
unknown: motor/nonmotor

Question 8

differentials for seizures

Answer 8

■ Syncopal episodes e.g vasovagal syncope
■ Cardiac issues including reflex anoxic seizures, arrythmias
■ Movement disorders e.g Parkinsons, Huntingtons
■ TIAs
■ Migraines
■ Non-epileptic attack disorders (formerly pseudo-seizures)

Question 9

benzodiazepines

Answer 9

1st line GABAa agonists
Be wary of addiction, cardiovascular collapse, airway issues
■ Also used as anxiolytics, sleep aids, alcohol withdrawal

Question 10

benzodiazepine example

Answer 10

iv lorazepam
rectal diazepam
buccal/intranasal: midazolam

Question 11

diagnosis

Answer 11

Electroencephalography, MRI,

Question 12

Na channel blockers

Answer 12

slows recovery of neurones from inactive to closed state
■ Reduces neuronal transmission

carbamazepine, phenytoin
sodium valproate
lamotrigine

Question 13

carbamazepine #

Answer 13

■ Suicidal thoughts ■ Joint pain ■ Bone marrow failure

Question 14

phenytoin

Answer 14

Exhibits zero order kinetics- care when adjusting doses
■ Specific side effects: 
■ Bone marrow suppression 
■ Hypotension
 ■ Arrythmias (IV use)

Question 15

sodium valproate

Answer 15

mix of GABAa effects and sodium channel blockade
■ Liver failure ■ Pancreatitis ■ Lethargy
e should not be prescribed to any woman of childbearing age unless they meet the conditions of a pregnancy prevention programme ,

Question 16

Lamotrigine

Answer 16

focal epilepsy safe in pregnancy

Question 17

levetiracetam

Answer 17

Stops the release of neurotransmitters into synapse and
reduces neuronal activity,
safe in pregnancy

Question 18

side effects of anti epileptic drugs

Answer 18

■ Tiredness/drowsiness
■ Nausea and vomiting
■ Mood changes and suicidal ideation ■ Osteoporosis
Rashes
can cause anaemia, thrombocytopenia or bone marrow failure

Question 19

drug drug interactions

Answer 19

warfarin-monitoring
should not drink alcohol
■ Carbamazepine and phenytoin may decrease the effectiveness of oral contraceptive pills, some antibiotics
■ Valproate can increase the plasma concentration of other AEDs

Question 20

CYP inducers

Answer 20

• Phenytoin • Carbamazepine

Question 21

CYP inhibitors

Answer 21

valproate