antiepileptics6766665776545464356536645.ppt

anti pileptics

1. ANTIEPILEPTICS

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. CLASSIFICATION OF
ANTIEPILEPTICS
HYDANTOINS-Phenytoin, Mephenytoin
BARBITURATES- Phenobarbotone,
Mephobarbitone
DEOXYBARBITURATES - Primidone
IMINOSTILBENE - Carbamazepine
SUCCINIMIDE - Ethosuximide
GABA transaminase inhibitor - Valproic
acid
BENZODIAZEPINES -
Diazepam,Clonazepam, Lorazepam

5. CLASSIFICATION (Cont...)
NEWER AGENTS
GABA analogs -
Gabapentin ,vigabatrin
OTHERS - Zonisamate,felbamate

6. PHENYTOIN
PHARMACOLOGICAL ACTION
CNS - Phenytoin has good anti
seizures activity and is one of the
most effective drugs against
generalized tonic-clonic seizures and
partial seizures.

7. MECHANISM OF ACTION

8. Phenytoin
Blocks Na + Channels in Post
Synaptic Neuron
Inhibits the action Potential of
Neurons

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

10. 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.

11. 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.

12. 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.

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

14. 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

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

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

17. 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

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

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

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

21. 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.

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

23. 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 - Diazepam