definition,types,pathophysiology,classifications,mechanism of actions,uses,affects

1. ANTIEPILEPTIC
S

2. DEFINITION
Epilepsy
Epilepsy is a chronic disorder of brain
function characterized by recurrent
seizures often accompanied by episodes
of unconsciousness or amnesia.
Seizure
Seizure is a transient alteration in
behaviour because of disordered firing
of group of neurons.

3. SEIZURE TYPES

4. PARTIAL SEIZURE

10. CLASSIFICATION OF
ANTIEPILEPTICS
.HYDANTOINS-Phenytoin,
Mephenytoin
.BARBITURATES- Phenobarbotone,
Mephobarbitone
.DEOXYBARBITURATES: Primidone
.IMINOSTILBENE -Carbamazepine
.SUCCINIMIDE - Ethosuximide

11. .GABA transaminase inhibitor -Valproicacid
.BENZODIAZEPINES -
Diazepam,Clonazepam, Lorazepam
CLASSIFICATION (Cont...)
NEWER AGENTS
GABA analogs - Gabapentin ,vigabatrin
OTHERS - Zonisamate,felbamate

13. GENERAL Mechanism of
Action of antiepileptics.
.Anti epileptic drugs act primarily by
Blocking the initiation or spread of seizure.
.Decrease propagation of action potentials
.  Na+, Ca++ influx (delay depolarization
/ prolong repolarization)
. Cl- influx (hyperpolarizemembrane)
.Decrease glutamate release

15. PHENYTOI
N
PHARMACOLOGICALACTION
CNS - Phenytoin has good anti seizures
activity and is one of the most effective
drugs against generalized tonic-clonic
seizures and partial seizures.

16. MECHANISM OF
ACTION

17. Phenytoin
Blocks Na + Channels in Post
Synaptic NeuronInhibits the action
Potential of Neurons

18. ADVERSE EFFECTS
Nausea, vomitting, epigastric
pain Hypersensitivity
Megaloblastic anemia Teratogenicity
–when taken to the pregnant lady
,it produce fehydantoin syndrome
(Cleft Palate, Cleft lip &
Microcephaly)
Hyperglycemia

19. USES
1.Generalized tonic clonic seizures
and partial seizures
2.Status epileptics –phenytoin is used
by slow IV Injection.
3.trigeminal neuralgia – as an
alternative to carbamazepine.
4.cardiac arrhythmias- phenytoin is
useful in digitalis induced arrhythmias.

20. Drug interaction
Phenytoin is an enzyme inducer.
phenobarbitone competitively inhibit s
phenytoin metabolism.
Carbamazepine and pheytoin enhances
each others metabolism.
Valproate displace protein bound and
may result in phenytoin toxicity.
Antacid  absorption of phenytoin.

21. Fosphenytoin
It is a prodrug of phenytoin that has
certain advantages over phenytoin for
Parenterally use:
It is quickly converted to phenytoin in
the body.
More potent.
Less cardiotoxic.
Safer on the intestine.

22. PHENOBARBITONE
It has specific antiepileptic activity.
Primidone which is rarely used .
Phenobarbitone is effective in tonic-
clonic seizures and ineffective in absence
of seizures.

23. MECHANISM OF ACTION
Acts on the Synapse
Enhance the action of Inhibitory
neurotransmitters (Eg. GABA)
Suppresses the excitatory neurotransmitters (Ach)
Opens Cl – ion Channels
Decreases the Seizures

24. Pharmacokinetics
Oral Absorption
50 % bounds to plasma
proteins
Metabolizes in liver
Excreted via urine

25. ADVERSE EFFECT
Sedation, Megaloblastic anemia,
Osteomalacia,
Ataxia.
Skin rashes
USES
Generalized tonic –clonic
seizures Partial seizures

26. CARBAMAZEPINE
Carbamazepine is a tricyclic
compound Anti seizure activity
It has good Anti seizure activity .its
mechanism of action and anti epileptic
action are similar to phenytoin.
Carbamazepine is also used in the
treatment of trigeminal neuralgia

27. ADVERSE EFFECTS
Drowsiness
Vertigo
Nausea &
Vomiting Ataxia
USES
Generalized Tonic – Clonic Seizures
Simple & Complex, Partial Seizures
Trigeminal Neurolgia

28. VALPORIC ACID MoA
Enhances the level of GABA (se
Metabolism of GABA)
Blocks Na + Channels
Decreases low threshold Ca + current in
thalamus
Reduce Seizure

29. ADVERSE EFFECTS
Sedation, Rashes, Ataxia and Tremors
USES
Partial & Generalized Seizures
Useful particularly in Absence Seizures (Petit
Mal Seizures)
Generalized Tonic Clonic Attacks

30. BENZODIAZEPINE
Diazepam is the drug of choice in status
epilepticus.
Clonazepam is a potent anti epileptic drug
useful in absence and myoclonic seizures.
Nitrazepam is used for treatment of
myoclonic seizures.

31. NEWER ANTI
EPILEPTICS
Gabapentin – It is a highly lipid soluble
drug.
It crosses the BBB.
Effective in tonic clonic seizure
Exact MoA is unknown.

32. CHOICE OF ANTI SEIZURE DRUGS
.Simple / Partial Seizure – Carbamazepine,
Phenytoin, Valproic Acid
.Complex / Partial Seizure - Carbamazepine,
Phenytoin, Valproic Acid
.Partial with Secondarily Generalized -
Carbamazepine,Phenytoin,Valproic.Acid
.Absence Seizures – Valproic Acid
.Tonic Clonic Seizure - Carbamazepine, Phenytoin,
Valproic Acid
.Tonic Clonic + Absence Seizure – Valproic Acid
.Myoclonic Seizures – Diazepam, Valproic Acid
.Status Epilepticus – Diazepam, Phenytoin, GA
.Febrile Convulsion – Diazepa

33. USESOF
ANTIEPILEPTICS

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