Useful for both B.Pharmacy and M.Pharmacy students

1. Anti-epileptics
Presented by
K.Lakshmi
Department of pharmacology
Assistant professor
SSPC

2. Definitions
Epilepsy :- It is a group of chronic neurological
disorder of CNS in which the nerve cell
activity becomes distrupted causing seizures or
unusual sensation or loss of consciousness.
Seizures:- Abnormal CNS electrical activity.
Convulsions:- Prolonged contractions of skeletal
muscles.

3. What Is the Difference Between
Epilepsy & Seizures?
A seizure is a symptom of epilepsy

5. Etiology
• Congenital defects, head injuries, trauma, hypoxia
• Infection e.g. meningitis, brain abscess, viral
encephalitis
• Depressed skull, fractures
• Brain tumors,
• Drug withdrawal, e.g. CNS depressants
• Fever in children (febrile convulsion)
• Hypoglycemia, hypocalcaemia
TRIGGERS:
Fatigue, stress, poor nutrition, alcohol and sleep
deprivation.

6. Types of seizures

8. Partial/Focal seizures
When seizures appear to result from abnormal activity in just
one part of the brain, they're called focal or partial seizures.
These seizures fall into two categories.
Simple focal seizures
These seizures don't result in loss of consciousness. They
may alter emotions or change the way things look, smell,
feel, taste or sound. They may also result in involuntary
jerking of part of the body, such as an arm or leg, and
spontaneous sensory symptoms such as tingling, vertigo.
Complex focal seizures
These seizures alter consciousness or awareness, causing
you to lose awareness for a period of time. Complex focal
seizures often result in staring and no purposeful
movements — such as hand rubbing, chewing, swallowing
or walking in circles.

9. Generalized seizures
Seizures that seem to involve all of the brain are called
generalized seizures. Six types of generalized seizures exist.
Absence seizures (also called petit mal)
These seizures are characterized by staring and subtle body
movement, and can cause a brief loss of awareness.
Tonic seizures
These seizures cause stiffening of the muscles, generally
those in your back, arms and legs and may cause you to fall
to the ground.
Clonic seizures
These types of seizures are associated with rhythmic, jerking
muscle contractions, usually affecting the arms, neck and
face.

10. Myoclonic seizures
These seizures usually appear as sudden brief
jerks or twitches of your arms and legs.
Atonic seizures
Also known as drop attacks, these seizures cause
you to lose normal muscle tone and suddenly
collapse or fall down.
Tonic- clonic seizures (also called
grand mal)
The most intense of all types of seizures, these are
characterized by a loss of consciousness, body
stiffening and shaking, and sometimes loss of
bladder control or biting your tongue.

12. ANTI EPILEPTIC DRUGS
Definition:- Anti epileptics are the drugs which are
used to treat epilepsy.
Classification:-
1. Barbiturates :- Phenobarbitone,Primidone
2. Hydantoins:- phenytoin, phosphenytoin
3. Iminostilbenes:- carbamazepine, oxcarbazepine
4. Succinimides:- ethosuximide
5. Aliphatic carboxylic acid:- Valproic acid,
6. Benzodiazepines:- clonazepam, diazepam,lorazepam
7. New compounds:- gabapentin, lamotrigine,
tiagabine, topiramate, vigabatrin, zonisamide,
felbamate

13. MECHANISM OF ACTION OF
ANTIEPILEPTIC DRUGS:-
Three main mechanisms –
• Enhancement of GABA action
• Inhibition of sodium channel function
• Inhibition of calcium channel
function.
Other mechanisms include -
- Inhibition of glutamate release and
- Block of glutamate receptors.

14. (1)Enhancing GABA synaptic
transmission:-
barbiturates, benzodiazepines, gabapentin,
levetiracetam, tiagabine, vigabatrin,
topiramate, valproate; the result is
increased permeability to chloride ion,
which reduces neuronal excitability.
Valproate and topiramate block GABA
transaminase and tiagabine blocks reuptake
of GABA.

16. (2) Reducing cell membrane permeability to
voltage-dependent sodium channels:
carbamazepine, lamotrigine, oxcarbazepine,
phenytoin, topiramate, valproate.

17. (3) Reducing cell membrane permeability to
calcium T-channels: valproate, ethosuximide;
the result is diminishing of the generation of
action potential.

19. AED: adverse effects
Phenytoin:- Diplopia, ataxia, sedation, gingival
hyperplasia, hirutism, teratogenesis.
Carbamazepine:- Diplopia, ataxia, blood dyscrasias,
teratogenesis.
Valproate:- GI distress, hepatotoxicity.
Ethosuximide:- GI distress, headache, dizziness.
Vigabatrin:- Sedation, confusion, visual field defects.
Lamotrigine:- sedation, ataxia, dizziness, nausea, skin
rash, dermatitis.
Felbamate:- Aplastic anemia, hepatitis.
Tiagabine:- Dizziness, sedation, ataxia.
Gabapentin:- sedation, dizziness, ataxia.

23. Pharmacological actions of
Not CNS depressant
But muscular rigidity and excitement at
toxic doses
Abolish tonic phase of GTC seizure
No effect on clonic phase
Prevents spread of seizure activity
Tonic-clonic epilepsy is suppressed but
no change in EEG
In CVS – depresses ventricular
automaticity, accelerates AV conduction

24. Pharmacokinetics:
Slow oral absorption
80-90% bound to plasma protein
Metabolized in liver by hydroxylation and
glucoronide Conjugation
Elimination varies with dose –first order to zero
order
T1/2 is 12 to 24 hrs
Cannot metabolize by liver if plasma conc. Is
above 10 mcg/ml

25. Adverse effects:-
P-450 interactions
Hirsutism
Enlarged gums
Nystagmus
Yellow-browning of skin
Teratogenicity
Osteomalacia
Interference with B12 metabolism (hence
anemia)
Neuropathies: vertigo, ataxia, headache

26. Drug Interactions:
1. Phenytoin and carbamazepine increases
each others metabolism
2.Induces microsomal enzyme – steroids,
digitoxin etc
3. Phenytoin metabolism inhibition – by warfarin,
isoniazid etc.
4.Sucralfate – decreases phenytoin absorption
Uses:-
• Partial seizure
• Generalized (including tonic-clonic) seizures

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31. You will win not
immediately
but
definitely you
will win