modify neurologic drugs for latest presentation

7/27/2019 MODIFY Neurologic Drugs for latest presentation.

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Convulsion Drugs

Rph KASHIF ALI

National institute of blood diseases andbone marrow transplantation

HOSPITAL


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Seizures

Seizures involve a brief episode of abnormalelectrical activity in nerve cells of the brain

that may be accompanied by changes inbehavior or appearance

Convulsion is a tonic-clonic type of seizure

characterized by spasmodic contractions ofmuscles


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Seizures cont,

May be caused by hypoglycemia, fever,electrolyte imbalances, overdoses of drugs,

withdrawal of alcohol or sedative-hypnoticdrugs or as a result of epilepsy


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Lab investigation

Serum glucose

Serum sodium

Pregnancy test in woman ofchildbearing age

Lumbar puncture


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Types of Seizures

Partialbegin in a specific area of the brain.Movements may be automatic, repetitive or

aversive. Behavior may be bizarre. Generalizedbilateral and symmetric and w/o

discernible point of origin in the brain. Tonic-clonic. Tonic phase is sustained skeletal

contraction, clonic phase is rapid and rhythmicjerking movements.

E.g. Tonic clonic, atonic, absence seizures and

myoclonic seizure


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Types of Seizures

Absenceabrupt alterations inconsciousness that last only seconds

Status Epilepticus is a life-threatening,generalized tonic-clonic convulsions lasting

for several minutes or at close intervals.Hypotension, hypoxia and cardiacdysrhythmias may occur.


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Antiseizure Drugs

Also called antiepileptic drugs oranticonvulsants

The term seizure and convulsion maybe used interchangeably

Drugs can usually control the seizure

activity but do not cure the underlyingdisorder


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Antiepileptic Drugs (AEDs)

Mechanisms of action

Suppress seizures by decreasing movement

of ions into nerve cells, altering the activityof neurotransmitters (GABA and glutamate)or both.

Actions of drugs may increase GABA(inhibitory), decrease glutamate(excitatory) or affect Na+ and Ca++ ions

thus decreasing responsiveness


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Mechanism of Action

Decrease CNS stimulation and preventthe excessive electrical discharge of the

seizure focus in the CNSAlso exert a protective effect on

surrounding cells to prevent their

discharge


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Ideal drug

The choice of an anticonvulsant is based firston its proven efficacy in specific types of

seizure or epileptic syndromes A third generation (stiripentol, eterobarb,

zonizamide) should lead to the idealantiepileptic drug capable of preventing and

treating epilepsy


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Principles of Treatment

Four main mechanisms of action underlie thebeneficial pharmaceutical effect of AED.

Blockade of the voltage-dependent sodiumchannels

Increased GABAergic inhibition ofneurotransmission

blockade of glutaminergic transmission

blockade of type T calcium channels


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Principles of Treatment

Sodium channel blockers: oxcarbazepine,carbamazepine, felbamate, valproic acid

GABAergic drugs: vigabatrin, gabapentin,tiagabine, benzodiazepines, pregabalin

Glutaminergic drugs: lamotrigine, topiramate

Calcium channel inhibitors: ethosuximide,zonisamide


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Indications

Maintenance treatment of epilepsy

Stop tonic-clonic seizures

Status epilepticus

Treatment of choice for statusepilepticus is lorazepam

AEDs also useful in bipolar disorder andfor neuropathic pain


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Classification

Phenytoin

Fosphenytoin

Carbamazepine

Diazepam

Topiramate Gabapentin

Levetiracetam

Phenobarbital


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Enzyme inducers

Carbamazepine, ethosuximide,phenobarbital,

phenytoin, primidone, and valproic acid


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Enzyme inhibitors

Ethosuximide and valproic acid,


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Contraindications

In patients with CNS depression

Hypersensitivity reaction

Caution in hepatic or renal dysfunction

Caution in pregnancy due to teratogeniceffect in animals


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Function of anticonvulsants

Suppresses sodium influx by binding tosodium channel

Suppresses CA influx

Increases the action of GABA and resultingin suppression seizures activity


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SIDE EFFECTS

side effects of AEDs are drowsiness,irritability, nausea, skin rash, lack of

physical co-ordination and, in children,hyperactivity. Emotional changes may alsooccur. Occasionally, a drug will actually

increase, rather than decrease, the numberof seizures a person experiences


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Pregnancy and lactation

Phenobarbital

( congenital anomaly

Topiramate

( cleft palate )

Gabapentin

( safety in

Pregnancy not

Established)

Fosphenytoin

( congenital

Abnormality)

Diazepam

( congenital

malformation

Sodium valproate

( neural tube defect

Broad nasal bridge

Cleft lip)

Anticonvulsants


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"The person who takes medicine

must recover twice, once from

the disease and once from the

medicine."

- William Osler, M.D.


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THANK YOU

modify neurologic drugs for latest presentation

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