ANTIEPILEPTICS Dr: Samah Gaafar Hassan

 a periodic recurrence of seizures with or without convulsions.  A convulsion implies violent, involuntary contraction(s) of the voluntary muscles.  A seizure results from an excessive discharge of cortical neurons and is characterized by changes in electrical activity as measured by the electroencephalogram (EEG).

 The goal of treatment is to control or reduce the frequency of seizures and ensure compliance, allowing the patient to live as normal a life as possible. Complete suppression of seizures must be balanced against tolerability of side effects, and the patient should be involved in defining the balance.

 The mechanism of action of most AEDs includes effects on ion channels (sodium and calcium), inhibitory neurotransmission (GABA), or excitatory neurotransmission (glutamate and aspartate).

 Blocks voltage-gated sodium channels.  Partial seizures, generalized tonic clonic, trigeminal neuralgia.  An enzyme inducer. (own induction)  Has active metabolite carbamazepine-10,11- epoxide.  S.E  Neurosensory side effects (e.g., diplopia, blurred vision, nystagmus, ataxia.  Hyponatremia.  Drug interaction valporic acid, clarithromycin, errythromycin.

 inhibits type T- Ca channels.  Only for absence seizures.  FELBAMATE:  Broad spectrum antiepileptic.  glycine receptor antagonist.  Aplastic anaemia & hepatitis.

 second-line agent for patients with partial seizures.  Less side effect & less drug interaction  In elderly.  Renal excretion.  LAMOTRIGINE:  Broad spectrum.  Drug interaction enzyme indution & inhibition.  Eldery.

 Enhances the GABA effect.  Choice in neonatal seizures.  In SE.  PHENYTOIN:  Partial, generalized tonic clonic & SE.  90% binding to plasma protein.  Is an enzyme inducer.  Zero-order elimination.  S.E: ataxia, nystagmus, gengival hypertrophy.  Folic acid deficiency.

 Partial & primary generalized.  >90% is plasma protein bound.  Is an enzyme inhibitor.  S.E: hepatotoxicity, pancytopenia, POS, hair loss, menstrual irregularities.

 2-5 yrs.  Compliance.  Barbiturates and phenytoin are associated with congenital heart malformations and facial clefts. Valproic acid and carbamazepine are associated with spina bifida.

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