The document discusses epilepsy, a chronic brain disorder characterized by recurrent seizures. It provides details on the types of seizures, experimental models used to study epilepsy, antiepileptic drugs and their mechanisms of action, diagnostic tools, myths and facts about epilepsy, and references. Epilepsy affects people of all ages worldwide and imbalances in neurotransmitters like glutamate and GABA are believed to underlie seizure mechanisms.

1. Abdul Waheed
M.Pharm-Pharmacology
Department of Pharmacology
Amity University Noida

2. Epileptic seizure
 Epilepsy is a chronic brain disorder
 characterized by tendency to recurrent seizures or fits.
 The seizures can leads to loss of consciousness, disturbance of
movement, muscle spasms, autonomic and mental functions.
 At least 12 millions people in India and 65 millions of people
worldwide are affected.
 Epilepsy affects all the ages, races, sex, education, economic
status and social classes across all geohraphical boundaries

3.  As per WHO epilepsy is one of the most common serious brain
disorders that affects not only the individual, but also has impect
on family and the society in general.
 Mechanism of epilepsy is believe to be imbalance in
neurotransmitter release i.e. abnormally increase the level of
excitatory neurotransmitter glutamate while decrease in inhibitory
neurotransmitter GABA.
 Several types of epilepsy have now been linked to defective
genes for ion channels that control the flow of ions and regulate
neuron signalling.
 During the seizure, neurons may fire 500 times faster than normal
neuron.

4. Types of seizures
Generalised seizures
 Tonic - clonic
 Tonic
 Clonic
 Atonic
 Absence
 Myoclonus
Focal (partial) seizures
 Simplex partial
 Complex partial
 Partial onset with secondary
generalisation

5. Generalised tonic-clonic seizure
(grand mal)
 The most common seizure
 Major epilepsy
 Last for 1-2 min
 symptoms:
 Cry, loss of consciousness, fall
 Tonic phase- generalised muscle contraction, apnoea
 Clonic phase- rhythmic contraction of muscles, tongue
bite, foaming, enuresis
 Terminal sleep and gradual regaining of consciousness
(transient confusion)

6. Absence
 Cognitive dysfunction with a sudden onset
 lasting ½ min.
 Minor epilepsy
 Stare, expressionless face; arrest of ongoing activity;
generally no motor phenomena
 Loss of consciousness
 EEG shows characteristics 3 cycles per second spike
and wave pattern.
 Occurs in genetic (idiopathic) epilepsies, mostly in
children

7. Myoclonic seizure
 Sudden, quick, arrhythmic muscle contraction
 No loss of consciousness
 EEG: generalised polyspike and wave activity
 Occurs in genetic (idiopathic) epilepsies
 Not only an epileptic phenomenon- it can be the sign
of diffuse encephalopathies

8. Atonic seizures
 Akinetic epilepsy
 Unconsciousness
 Relaxation of all muscles due to excessive inhibitory
discharge
 Patient may fall

9. Simplex partial seizures
 Cortical focal epilepsy
 Last ½ - 1 min.
 No loss of consciousness
 Symptoms depend on area of brain involved:
 Motor
 Sensory
 Autonomic
 Psychosensory

10. Complex partial seizures
 Temporal lob epilepsy
 Origin is most often in the temporal lobe
 A common seizure type in adulthood
 Loss of consciousness: stare, ‘going blank’
 Last 1-2 min.
 Automatisms:
 oral automatisms
 fiddling with the hands
 Confused behaviour and purposeless movements

11. Experimental models
 Maximal electroshock method
50 mA for 0.2 second
 Pentylenetetrazol (PTZ) clonic seizure
70mg/kg
 Chronic focal seizure
Application of alumina cream on the motor cortex of
monkey
 Kindled seizure
90mk/kg

12. AEDs
Old
 Primidon
 Phenobarbital
 Phenytoin
 Clobazam
 Clonazepam
 Ethosuximid
 Valproate
 Carbamazepine
New
 Lamotrigine
 Oxcarbazepine
 Topiramate
 Gabapentin
 Felbamate
 Vigabatrin
 Levatiracetam
 Zonisamide
 Tiagabin

13. Mechanism of action of AEDs
Inhibition of voltage gated Na, Ca
channels
Na: phenytoin, carbamazepine,
oxcarbazepine, lamotrigine,
topiramate, felbamate, zonisamide
Ca: ethosuximid, valproate?
lamotrigine, topiramate, zonisamide
Potentiaton of GABA mediated
inhibition
phenobarbital, benzodiazepins,
vigabatrin, tiagabine, topiramate,
valproate, gabapentin, felbamate
Decrease of glutamate mediated
excitation
felbamate, topiramate

14. Side effects of AEDs
 Allergy
 Central nervous system side effects (dose dependent)
 drowsiness, headache
 dizziness, dysequilibrium
 cognitive dysfunction (memory)
 Idiosynchratic reactions / chronic side effects
 bone marrow suppression
 hepatic failure
 rash
 weight gain, weight loss
 tremor
 polycystic ovary syndrome
 visual field defect

15. Diagnostic tools
 Primary diagnosis of epilepsy includes eye–witness and family
history.
 Electroencephalograph (ECG) is the cornerstone for diagnosis
of epilepsy and measures the brain wave activity.
 Neuroimaging like computed tomography (CT) scan, magnetic
resonance imaging (MRI) and positron emission tomography
(PET) techniques are used to diagnose abnormalities in
structure and function of brain.
 Video recording is also useful for the monitoring of epileptic
events.

16. Myths and Facts
 Myth: Epilepsy is because of possession by evil sprit and hence
sorcery is the treatment.
Fact: Neurological disorder, drugs to treat
 Myth: Epilepsy is mental illness
Fact: No, it’s a brain disorder
 Myth: People with epilepsy are below normal in their intelligence
Fact: epilepsy does not affect intelligence or memory.
 Myth: Marriage cure epilepsy
Fact: off course not! Medicines do.
 Myth: Seizure can be stopped by giving a key in the hand or
making a person to smell onion or shoe
Fact: False, the attack stops on its own and not due to the above
factors.

17. References
 KD Tripathi, Essential of medical pharmacology, jaypee
publication, 6th edition, p.no. 401.
 Schmidt D, Schachter S.C.Drug treatment of epilepsy in adults.
BMJ. 2014 Feb 28;348:g254.
 Aristea S. Galanopoulou, Merab Kokaia, Jeffrey A. Loeb, Astrid
Nehlig, Asla Pitkänen, Michael A. Rogawski, Kevin J.
Staley, Vicky H. Whittemore, and F. Edward Dudek. Epilepsy
Therapy Development: Technical and Methodological Issues in
Studies with Animal Model. Epilepsia. Aug 2013; 54(0 4): 13–23.