Antiepileptic Drugs PDF
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This document provides basic information about antiepileptic drugs, including causes, diagnosis, mechanisms of action, and therapeutic uses. It also classifies different types of epilepsies. It's a useful resource for medical professionals learning about antiepileptic treatments.
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Part 5 5: Antiiepileptiic Drugs s █ Basiic inform mation Epilepsy, a chronic disease, occurs in appproximatelyy 1% of the popu lation. The cauuse of most cases of epilepsy iss unknown n, alth hough som me people de...
Part 5 5: Antiiepileptiic Drugs s █ Basiic inform mation Epilepsy, a chronic disease, occurs in appproximatelyy 1% of the popu lation. The cauuse of most cases of epilepsy iss unknown n, alth hough som me people develop e epilepsy as a the result of brain b injury y, stroke, b brain tumor, andd drug toxicity. Ge enetic muttations arre linke ed to a sm mall proportion of the e disease. Epilleptic seizu ures resultt from exc cessive and d abn normal cortiical nerve cell c activity in the brain n. Thee diagnosiss typicallyy involves ruling outt other conditions thhat cause similar neuurological symptoms. This m may be confirmed d by braain imagin ng and elec ctroencephhalogram (EEG) ( but a normal te est does not excludee the condition. Antiepileptic drugs d (AED Ds) are effe ective for about a 80% % of these patients. Lifelong L trea atment mayy be neces ssary. It m may take we eeks to es stablish ade equate dru ug plasma levels and d to determ mine the ade equacy of therapeutiic improve ement. Lac mpliance iis respons ck of com sible for manny treatme ent failures. AED Ds are mo ost effectiive and ha ave the le east adverse effectts when they are use ed as mono otherapy. Add dition or withdrawal w of any drrug should d be gradual, becauuse seizurres may occ cur on withdrawal. Som me AEDs are a terato ogenic; thiis may ca all for the reduction or termina ation of therrapy during g pregnanc cy. Classiification of o epileps sies: Epilepssies are characteriz c zed by eitther focall or generalized ab bnormal neuronal n discharrges. Drugg selection n, based o on seizure classifica ation, is lissted below w in the order o of general choice. c Simple Loc calized disc charge; co onsciousne ess is 1. Carbama azepine partial not altered. 2. Lamotriggine seizures Partial 3. Valproic acid Complex x Loc calized disc charge tha at becomes s partial widespread; aaccompanied by loss s of con nsciousnesss. 345 Tonic–clo onic Draamatic convvulsions with w either jerking 1. Valproic acid (grand ma al) of the extremiities or rigidity of the entire 2. Lamotriggine boddy; accomppanied by loss of 3. Carbama azepine connsciousnesss. Generalized Absence Suddden onsett of altered d consciouusness 1. Ethosuximide seizures (petit mal)) thatt lasts 10–4 45 secondds, with up to 2. Valproic acid hun ndreds of sseizures peer day; beg gins in 3. Clonazeppam chilldhood or adolescen nce. Myoclonic Lighhtning-like e jerks of one or more e 1. Valproic acid syndromes extrremities occcurring sin ngly or in bursts b 2. Lamotriggine of up u to a hun ndred; accompanied by alte eration of c consciousn ness. Status epilep pticus: Pro olonged se eizure (>20 0 min) of a any of the types prev viously desscribed; th he most com mmon is liffe-threaten ning generaalized tonic–clonic sttatus epileepticus. 1. Dip phenylhyd dantoin (P Phenytoin n) Mechaanism: it blocks Na a+, K+ andd Ca2+ channeels in the brain (and d heart) le eading to deccrease prropagation n of abn normal impulse es. It prooduces so ome degrree of drowsin ness. Therap peutic use es Parttial and geeneralized seizures s Stattus epileptticus: it sho ould be givven i.v. in the t form of fosphenyytoin (prod drug). Ven ntricular arrrhythmia. Advers se effects – CNS S: Nystagmus, diplo opia, ataxia a. – Heppatotoxicityy. – Miccrosomal enzyme ind duction. – Bonne marrow depressio on & Mega loblastic anemia a e to ↓ folicc acid). (due – Teraatogenicityy: craniofacial abnorm malities. – Gingival hype erplasia: 2ry 2 to incrreased ex xpression of platelett derived growth facttor (PDGF)). – Lym mphadenop pathy. 346