Brief blackout followed by period of confusion (the person cannot
remember a period of time)
Frothing at the mouth
Eye movements
Loss of bladder or bowel control
Mood changes such as sudden anger, unexplainable fear, panic,
joy, or laughter
Shaking of the entire body
Sudden falling
Tasting a bitter or metallic flavor
Teeth clenching
Temporary halt in breathing
Uncontrollable muscle spasms with twitching and jerking limbs
Epilepsy ???
group of disorders of the CNS with brief episodes
(seizures) of loss of disturbance of consciousness
with or without characteristic body movements
Classification of epilepsy
GENERALISED SEIZURES
1.
Generalised tonic-clonic seizures (GTC, grand mal): auraunconsciousness-tonic spasm-clonic jerking –prolonged sleepdepression of all CNS functions. Commonest, lasts 1-2min
2.
Absence seizures (petit mal) : momentary loss of consciousness,
freezes and stares in one direction, no muscular compartment
or jerking. prevalent in children
3.
Atonic seizures(akinetic epilepsy): unconsciousness with
relaxation of all muscles due to excessive inhibitory discharges.
4.
Myoclonic seizures: shock-like momentary contraction of
muscles of a limb or the whole body
5.
Infantile spasm(hypsahythmia): intermittent muscle spasm and
progressive mental deterioration
Partial seizures
•
Simple partial seizures(SPS, cortical focal): convulsions
confined to a group of muscles or localised sensory disturbance,
without loss of consciousness
•
Complex partial seizure : attacks of bizarre & confused
behaviour and purposeless movements emotional changes
lasting 2 min with impairment of consciousness.
•
Simple partial or complex partial seizures: the partial
seizures occur first and evolve into generalised tonic clonic
seizures with loss of consciousness
Classification
1. Barbiturate: Phenobarbitone
2. Deoxybarbiturate : Primidone
3. Hydantoin : Phenytoin, Fosphenytoin
4. Iminostilbene : Carbamazepine
5. Succimide : Ethosuximide
Classification
6. Aliphatic carboxylic acid: Valproic acid
7. Benzodiazepines: Clonazepam, Diazepam,Lorazepam,
Clobazam
8. Phenyltriazine : Lamotrigine
9. Cyclic GABA analogue : Gabapentin
10. Newer drugs: Vigabatrin, Topiramate, Zonisamide,
Levetiracetam
Phenobarbitone
• Cheapest and least toxic
• GABA receptor mediated synaptic inhibition
• Generalised tonic clonic seizures (GTC), simple partial
(SP), complex partial seizures
• 60mg, 1-3 times a day in adults, status epilepticus
• Adverse effects:
sedation, behavioral abnormalities, impairment of learning
& memory, hyperactivity in children, mental confusion
Phenytoin
• Prolongs inactivated state of voltage
sensitive neuronal Na+ channel
Phenytoin
• Absorption by oral route is slow
• widely distributed in the body and is 80-90% bound
to plasma proteins.
• Metabolized by hydroxylation & glucuronide
conjugation, follows zero order kinetics
Adverse effects of Phenytoin
At therapeutic levels:
Gum hypertrophy
Hirsutism
Coarsening of facial features
Hypersensitivity reactions
Megaloblastic anaemia
Osteomalacia
Hypergycemia
Fetal hydantoin syndrome
Adverse effects of Phenytoin
At high plasma levels:
cerebellar and vestibular manifestations
drowsiness,
mental confusion & hallucination
epigastric pain,
fall in BP
cardiac arrhythmia
Phenytoin
Interactions
• Phenobarbitone inhibits phenytoin metabolism
• Carbamazepine & phenytoin increase each others metabolism
• Valproate displaces protein bound phenytoin
• Chloramphenicol, isoniazid, cimetidine inhibits phenytoin
metabolism
• Phenytoin induces microsomal enzymes & increases degradation
of steroids, OCPs
Phenytoin
Uses
 Generalized tonic-clonic, simple & complex partial
seizures
 Status epilepticus
 Trigeminal neuralgia
 Cardiac arrhythmia
Carbamazepine
• MOA similar to phenytoin
P.K• oral absorption slow, 75% protein bound , metabolised by liver.
• Half life20-40 hrs but decreases due to autoinduction
A/E• sedation, dizziness, vertigo
• diplopia, ataxia
• vomiting, diarrhoea
• coma, cardiovascular collapse
• hypersensitivity reactions
• water retention
Enzyme inducer
Carbamazepine
Uses
• Most effective for CPS
• First choice- GTC, SPS
• Trigeminal neuralgia- drug of choice
• Manic depressive illness
Valproic acid
MOA
• Phenytoin like frequency dependant prolongation of Na + channel
activation
• Attenuation of Ca 2+ mediated T current
• Augmentation of release of GABA by inhibiting its degradation as
well as increasing its synthesis
P.K
• oral absorption good, 90% protein bound, completely metabolised
A/E
 anorexia, vomiting, drowsiness,
 tremor, alopecia, rashes,
 hepatitis, pancreatitis,
 spina bifida
Valproic acid
Uses
drug of choice in absence seizures
 GTCS, SPS, CPS
 myoclonic & atonic seizures
 mania & bipolar illness
Interactions
-plasma levels of phenobarbitone by inhibiting metabolism
-displaces phenytoin from protein binding
-valproate & carbamazepine induce each others metabolism
ETHOSUXIMIDE
• Reduces low threshold of Ca2+ ‘T’ type current in thalamus
PK
o completely absorbed from GIT
o not protein bound, evenly distributed in body
o metabolized in liver.
o Plasma half life - 48 hrs.
A/E
tiredness, mood changes, agitation, headache, drowsiness,
hypersensitivity reaction.
USES - Absence seizures.
DIAZEPAM
• Drug of Choice for Emergency control of Convulsions,
Tetanus, Febrile convulsions in children – Rectally.
• Sedative action,
• Rapid Development of Tolerance.
CLONAZEPAM
• Primarily used in absence seizures.
• Adjuvant in Myoclonic, Akinetic Epilepsy
CLOBAZAM
• Partial, secondarily generalized tonic-clonic,
absence, myoclonic, atonic seizures including
Respiratory cases.
Choice of Antiseizure Drugs
Sl
No.
Type of Seizure
1
2
First choice
Drugs
Second choice
drugs
Alternative/ Addon drugs
Generalised tonic-clonic / Carbamazepine,
simple partial with or
Phenytoin
without generalization
Valproate,
Phenobarbitone,
Primidone
Lamotrigine,
Gabapentin,
Topiramate
Complex partial with or
without generalization
Lamotrigine,
Gabapentin,
Clobazam,
Vigabatrin,
Topiramate,
Tiagabine
Carbamaz-epine,
Valproate,
Phenytoin
Sl
No.
Type of Seizure
First choice Drugs
Second choice drugs
Alternative/ Addon drugs
3
Absence
Valproate,
Ethosuximide
Clonazepam
Lamotrigine
Clobazam
4
Myoclonic
Valproate
Clonazepam
PrimidoneClobazam
, Topiramate
5
Atonic
Valproate
Clonazepam
Lamotrigine
Primidone
Lamotrigine
6
Febrile Seizures
Diazepam (rectal)
7
Status epilepticus Diazepam (i.v)
Clonazepam
(i.v)
---
Phenytoin (i.v)
Phenobarbitone (iv, im)
---
Gen. anaesthetics