Epilepsy & Anti-epileptic drugs pharmacology.pptx

Epilepsy is a chronic disorder of brain function characterized by recurrent seizures often accompanied by episodes of unconsciousness or amnesia. Types of seizures & Classification of anti-epileptic drugs.

1. Epilepsy & Anti Epileptic Drugs By Samiksha Tukaram Hamane. M Pharm (Pharmacology) Sem I Dr. Rejendra Gode Institute of Pharmacy, Amravati.

2. Content Introduction Types of seizures Classification

3. Introduction Epilepsy - Epilepsy is a chronic disorder of brain function characterized by recurrent seizures often accompanied by episodes of unconsciousness or amnesia. Due to sudden and excessive discharge of nerve impulse Third most common neurological disorder Symptoms depends on site of action Types of epilepsy a)Idiopathic - no specific anatomic cause for seizures. b)Symptomatic - many causes - drug use, head injury etc

4. Types of seizures There are two types - A)Partial - a)Simple partial - hyper active neurons in one lobe of brain b)Complex partial - complex hallucination Start one area travel to other area Time 30sec - 2 min B)Generalised - begin locally & spread abnormal impulse to both hemisphere. a)Tonic clonic - tonic means continuous contraction & clonic means contraction - relaxation eg falling, crying b)Absence - 3-5 yrs of children for 3-5 sec Rapid blinking of eye, one direction visual. c)Atonic - short loss of consciousness All muscle relax fall down d)Myoclonic - muscle contraction for several times

5. Classification of Antiepileptic SHYDANTOINS-Phenytoin, Mephenytoin BARBITURATES- Phenobarbitone, Mephobarbitone DEOXYBARBITURATES – Primidone IMINOSTILBENE – Carbamazepine SUCCINIMIDE – Ethosuximide GABA transaminase inhibitor - Valproic acid BENZODIAZEPINES - Diazepam, Clonazepam, Lorazepam GABA analouge - 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. MECHANISM OF ACTION Phenytoin Blocks Na + Channels in Post Synaptic Neuron Inhibits the action Potential of Neurons

7. ADVERSE EFFECTS Nausea, vomiting, epigastric pain Hypersensitivity Megaloblastic anaemia Teratogenicity Hyperglycemia USES Generalized tonic clonic seizures and partial seizures Status epileptics -phenytoin is used by slow IV Injection. trigeminal neuralgia – as an alternative to carbamazepine. cardiac arrhythmias- phenytoin is useful in digitalis induced arrhythmias.

8. DRUG INTERACTION Phenytoin is an enzyme inducer. phenobarbitone competitively inhibit s phenytoin metabolism. Carbamazepine and phenytoin enhances each others metabolism. Valproate displace protein bound and may result in phenytoin toxicity. Antacid absorption of phenytoin.

9. PHENOBARBITONE It has specific antiepileptic activity. Primidone which is rarely used Phenobarbitone is effective in tonic- clonic seizures and ineffective in absence of seizures. MECHANISM OF ACTIONS Acts on the Synapse Enhance the action of Inhibitory neurotransmitters ( Eg. GABA) Suppresses the excitatory neurotransmitters (Ach) Opens Cl-ion Channels Decreases the Seizures

10. PHARMACOKINETICS Oral Absorption 50% bounds to plasma proteins Metabolism in liver Excreted via urine ADVERSE EFFECT Sedation Megaloblastic anaemia Osteomalacia Ataxia Skin rashes USES Generalized tonic - clonic seizures Partial seizures

11. 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 ADVERSE EFFECTS Drowsiness Vertigo Nausea & Vomiting Ataxia

12. USES Generalized Tonic - Clonic Seizures Simple & Complex, Partial Seizures Trigeminal Neuroglia

13. VALPORIC ACID - GABA transaminase inhibitor MECHANISM OF ACTION Enhances the level of GABA Blocks Na + Channels Decreases low threshold Ca + current in thalamus Reduce Seizure

14. ADVERSE EFFECTS Sedation Rashes Ataxia Tremors USES Partial & Generalized Seizures Useful particularly in Absence Seizures Generalized Tonic Clonic Attacks

15. Thank you