Pharmacological treatments of epilepsy Flashcards
Antiepileptic drugs
Do not prevent the development of epilepsy
most drugs work to prevent the spread of epileptic discharges
Control epilepsy’s major symptoms: the seizure, not the cause
Increased activity in the brain may be attributed to
Increased membrane excitability
Increased efficiency of excitatory synaptic transmission- glutamate
Decreased efficiency of inhibitory synaptic transmission- GABA
Treatments aimed at opposing these actions
Reducing membrane excitability: Na+ channel blockers
Selective actions at the channel may control seizures without affecting normal transmission
Normal neuronal firing is not impaired
When neuronal activity increases, it is inhibited by drugs, thereby preventing seizure spread
Anticonvulsant drugs Na+ channel blockers
Phenytoin
Lamotrogine
Carbamezapine
Zonisamide
Lacosamide
Carbamezapine/ oxcarbazepine and eslicarbazepine
Competitively inhibit the voltage gate sodium channel by binding with the receptor in its inactive state
Prolongs the period between successive firings
Reducing efficiency of excitatory synaptic transmission- glutamate
Obvious target is glutamate receptors
Problem separating therapeutic effect from side effects
Perampanel
Non-competitive blockade of AMPA glutamate receptor
Reduce spread/ generalisation of seizure
Well tolerated with improved alertness
Controlling transmitter relase
Ca2+ channels voltage activated and require strong membrane depolarisation for gating
Several anticonvulsant drugs work this wat
Increase efficiency of inhibitory synaptic transmission- GABA
Focal epilepsy characterised by intermittent high amplitude discharges
Synchronous depolarisation followed by hyperpolarisation reflecting activation of GABA inhibition
Facilitators of GABAergic transmission
Sodium valproate
Benzodiazepines
Barbiturates
Tiagabine
Vigabatrin
Levetiracetam
High affinity synaptic vesicle protein 2A ligand
Modulates neurotransmitter release
Rapidly titrated and is effected
Keep patient alert by mood lowering/ agitation side effects
Ideal antiepileptic agent
Good efficiency, easy and rapid to titrate
No drug-drug interactions
No cognitive side effects
No bone marrow suppression
No affective/ drowsy side effects
Different routes of administration
Cost effective
Primary generalised epilepsy
Sodium valproate, lamotrigine first line
Broad spectrum antiepileptic drugs
Partial epilepsy
Carbamazepine, lamotrigine first line
All other antiepileptic drugs have efficacy
Drugs that exacerbate generalised seizure type
Phenytoin
Carbamazepine
Gabapentin/ pregabalin
