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anticonvulsant
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Is a group of chronic syndromes characterized by recurrent seizures with periods of consciousness
Balance between Inhibitory and Excitatory Transmitting Messages
Glutamate GABA
Excitatory messages from the cerebral cortex are modulated by deeper structures
Bursts of activity from the cortex are not modulated and these bursts spread
Is an abnormal, synchronized, electrical depolarization of neurons in the CNS
Is accompanied by characteristic changes in the EEG (electroencephalogram)
Major causes: Idiopathic CNS infections Fever Metabolic defects Cerebral trauma
Categories of Seizures
Partial (focal) Seizures
Partial seizure with secondary generalization
Primarily generalized Seizures
Partial (focal) Seizures Arise in one cerebral hemispheres
Simple partial seizure (Jacksonian epilepsy) Loses voluntary control of the affected parts
of the body but no alteration of consciousness Consisting of repetitive jerking of a
particular muscle groups which spreads, involving much of the body within about 2 minutes before dying out
Complex partial seizure (Psychomotor epilepsy) Altered consciousness, automatisms (rubbing or
patting movements), and behavioral changes (dressing, walking or hair-combing)
Partial seizure with secondary generalized seizure Focal seizures become generalized and is accompanied
by loss of consciousness
Generalized Seizures Arise in both cerebral hemispheres accompanied by loss of
consciousness Tonic-clonic (grand mal) seizure – increased muscle tone,
followed by spasms of muscle contraction and relaxation Absence (petit mal) seizures – brief loss of consciousness,
with minor muscle twitches and eye blinking Myoclonic seizures – rhythmic, jerking spasms Atonic seizure – sudden loss of all muscle tone Febrile (infantile) seizures
Status Epilepticus Is a condition in which patients experience
recurrent episodes of tonic-clonic seizure without regaining consciousness
Drugs Effective in Tonic-Clonic Seizures (Grand Mal) and Complex Partial Seizures Hydantoin derivatives
Phenytoin Mephenytoin
Barbiturate derivatives Mephobarbital Phenobarbital Primidone
Iminostilbene derivatives Carbamazepine
Drugs Effective in absence (Petit Mal) Seizures Succinamide
derivatives Ethosuximide
Oxazolidine derivatives Trimethadione Paramethadione
Propylpentanoic acid derivatives Valproic acid
Drugs Effective in Seizure disorders including Status Epilepticus Benzodiazepine derivatives
Diazepam Clorazepate Clonazepam
Hydantoin derivatives
Partial Seizure TreatmentSeizure TypeSeizure Type ProtocolsProtocolsSimpleSimpleComplexComplexPartial with 2° Partial with 2° generalizationgeneralization
Carbamazepine (iminostilbene) Carbamazepine (iminostilbene) –– DOCDOCPhenytoin (hydantoin)Phenytoin (hydantoin)Valproate (propylpentanoic acid)Valproate (propylpentanoic acid)PhenobarbitalPhenobarbitalPrimidonePrimidoneAdjuncts (used only if Adjuncts (used only if monotherapy is unsuccessful): monotherapy is unsuccessful): Lamotrigine, Gabapentin, Lamotrigine, Gabapentin, tiagabine, topiramatetiagabine, topiramate
Generalized Seizure TreatmentSeizure TypeSeizure Type ProtocolsProtocolsGrand MalGrand Mal Same as in Tx of partial seizures except Same as in Tx of partial seizures except
valproate is the DOCvalproate is the DOCPetit MalPetit Mal Ethosuximide (succinamide)Ethosuximide (succinamide)
Valproate - DOCValproate - DOCClonazepamClonazepamAdjunct: LamotrigineAdjunct: Lamotrigine
Myoclonic Myoclonic SeizuresSeizures
ValproateValproateSome benzodiazepinesSome benzodiazepines
Infantile SpasmsInfantile Spasms PrednisonePrednisoneVigabatrineVigabatrine
Status Status EpilepticusEpilepticus
Phenytoin with benzodiazepinePhenytoin with benzodiazepine
MOA : Suppress the Formation or Spread of Abnormal Electrical Discharges in the Brain
Reduces NMDAReceptor activation
Affect GABA Reduce Na+
conductance inhyperactive
neurons
Reduce Ca2+
currentthrough
T-channels
Felbamate
DiazepamVigabatrinTopiramateTiagabineGabapentin
Phenobarbital Carbamazepine PhenytoinFosphenytoinLamotriginePrimidone
Ethosuximide
Valproate
Toxic Effects of Phenytoin
What is the advantage of Phenytoin over other Antiepileptic drugs?
nonsedating
Toxic Effects of Phenytoin Megaloblastic anemia
Secondary to interference with folate metabolism Diminished deep tendon reflexes in extremities CNS depression Endocrine disturbances
Diabetes insipidus Hyperglycemia Glycosuria Osteomalacia
Hydantoin syndrome Teratogenic effects
What is the Drug of Choice for Trigeminal Neuralgia?Carbamazepine Adverse effects: Acute intoxication
Respiratory depression Stupor Coma
Severe liver toxicity Aplastic anemia Agranulocytosis Drowsiness Ataxia Nystagmus Vomiting
Most effective agent in Treating Myoclonic Seizures Valproic Acid
Broadest spectrum Also used in bipolar disorder and migraine Side effects
Hepatotoxicity Nausea and vomiting Sedation Tremor High incidence of neural defects during the first
trimester of pregnancy.
What is the Drug of Choice for Febrile Seizure? Phenobarbital
Which antiepileptic drug is chemically related to Phenobarbital? Primidone
Alternative choice for adults who have partial and generalized seizures
What are the 2 active metabolites of Primidone?
Phenobarbital
Phenylethylmalonamide (PEMA)
Which Antiepileptic is the Drug of choice for Absence Seizure?
Ethosuximide Toxic effects
Dizziness Agitation GI distress Confusion Blood dyscrasias Leukopenia Aplastic anemia Thrombocytopenia Skin reactions
Stevens-Johnson syndrome
END OF ANTIEPILEPTICS