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10 Cards in this Set
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- Back
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Phenytoin (diphenylhydatoin) |
Prodrug:fosphenytoin which contains no prophylene glycol(decr. BP),it is water soluble and also used for epilepticus MOA: use dependent Na+ channel inhibition as a result of state selective binding Good oral absorption--depends on formulation---iv injection is also possible . Pharmacokinetics:significant plasma protein binding,aspirin & sulfonamides may cause displacement. Metabolism:saturable metabolism by CYP2C9,CYP2C19 & it is dose dependent. Its level increases at a steady state.T1/2:6-24h---5days. It is a strong enzyme inducer,so it decreases other drugs efficacy. Also used for arrythmias SE: headache,dizziness,but no sedation, teratogenic. |
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Carbamazepine |
Chemically related to TCAs. MOA: use dependent Na+ channel inhib Metabolism:metabolized in the liverby CYP3A4,CYP2C9 with an active metabolite+ enterohepatic circulation. T1/2:36hrs. It is a strong enzyme inducer,more effective in psychomotor epilepsy. Also used for ethanol withdrawal & manic depression. SE: dizziness,double vision,sedation, water retention--dilutional hyponatremia. teratogenic(spinal bifida) |
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Phenobarbital |
Long acting barbiturate. MOA: +ve allosteric modulator of GABA a rec. It increases neuronal excitation. Has good oral absorption. Metabolism:T 1/2 100h. 75% in the liver25% unchanged in the urine. It is astrong enzyme inducer(CYP sys.). Given i.v for status epilepticus. SE: sedation,respiratory depression, teratogenic. |
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Primidone |
2-deoxy-phenobarbitol--partially metabolised into phenobarbital. MOA: Na+ channel blocker Orally used |
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newer antiepileptics |
oxcarbazepine eslicarbazepine acetate vigabatrin tiagabine gabapentin |
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Oxcarbazepine |
Keto analog of carbamazepine MAO: active metabolite mediates its action---S licarbazepine inhibits Na+ channel. Mainly for partial seizures. SE: more water retention but less enzyme induction than carbamazapine |
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eslicarbazepine acetate |
Prodrug of S-licarbazepine MOA:oral use--converted to S licarbazepine during first pass metabolism. SE:dizziness,headache,double vision,sedation. Used for partial seizures(once a day) |
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Vigabatrin |
MOA:irriversible inhibition of GABA transaminase--incr. GABA level--neuronal inhibition Used for partial seizure Metabolism:unchanged by the kidney SE:sedation,depression,visual disturbance |
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Tiagabine |
MOA: inhibits GABA reuptake--incr. GABA level--neuronal inhib. Used for partial seizure Metabolism: by CYP3A4 SE:sedation,dizziness, confusion |
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Gabapentin |
MOA:analog of GABA but does not act on GABA rec. Inhibits presynaptic Ca2+ channels--reduce neurotransmitter release Metabolism: unchanged by the kidne Others: for neuropathic pain and acute mania SE: sedation,ataxia,tremor,weight gain |
