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Monitorização terapêutica da carbamazepina
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Abstract(s)
A epilepsia é uma patologia que afeta o sistema nervoso, caracterizada por crises imprevisíveis com ou sem convulsões associadas. Atualmente sabe-se que a epilepsia tem origem em descargas súbitas anormais que ocorrem no cérebro e que afeta mais de cinquenta milhões de pessoas em todo o mundo.
O tratamento da epilepsia passa pela utilização de fármacos antiepiléticos e anticonvulsivantes. A escolha da terapêutica medicamentosa deve ser feita de acordo com o tipo de crise, a eficácia e efeitos adversos dos fármacos disponíveis, tendo como objetivo controlar as convulsões sem causar efeitos secundários. No mercado, está disponível uma variedade de fármacos, que são divididos em antiepiléticos clássicos e novos antiepiléticos. Os fármacos clássicos têm uma grande variabilidade farmacocinética, janelas terapêuticas estreitas, efeitos adversos e interações medicamentosas frequentes. Por outro lado, os fármacos antiepiléticos mais recentes têm perfis de segurança melhorados, janelas terapêuticas mais alargadas, são bem tolerados e apresentam menor variabilidade farmacocinética e menos interações medicamentosas.
Devido às características intrínsecas destes fármacos, nomeadamente no que concerne as interações com outros fármacos e as janelas terapêuticas estreitas, surge a necessidade de se realizar a sua monitorização terapêutica cujo principal objetivo é a individualização posológica. Assim, a quantificação da concentração do fármaco numa amostra biológica permite assegurar uma terapêutica individualizada aumentando a sua eficácia e diminuindo os efeitos adversos. Este doseamento pode ser efetuado por imunoensaios ou recorrendo a métodos cromatográficos. Os primeiros são utilizados em exames de rotina pois permitem uma avaliação rápida e precisa da concentração do fármaco. Por outro lado, os métodos cromatográficos são processos mais caros e morosos mas têm a vantagem de detetar e quantificar vários fármacos em simultâneo, para além de analisarem os seus metabolitos.
Epilepsy is a condition which affects the nervous system, characterized by unpredictable seizures, with or without associated convulsions. Currently it is known that epilepsy seizures are caused by abnormal discharges in the electrical activity of the brain and that it affects more than fifty million people around the world. Epilepsy treatment involves the use of antiepileptic and anticonvulsant drugs. The choice of drug therapy should be made according to the type of seizure, efficacy and adverse effects and the goal of therapy is to control seizures without causing side effects. There are several antiepileptic drugs available in the market, which are divided into classical and new antiepileptics. The classic drugs have high pharmacokinetic variability, narrow therapeutic range and significant adverse effects and drug interactions. On the other hand, the newer antiepileptic drugs, have better safety profiles, larger therapeutic range, better tolerability and alower pharmacokinetic variability and fewer drug interactions. Due to the intrinsic characteristics of these drugs, namely those regarding interactions with other drugs and the narrow therapeutic windows, its is necessary to perform its therapeutic monitoring whose main purpose is to individualize dosage. Thus, quantification of the concentration of a drug in a biological sample and can ensure an individualized therapy by increasing effectiveness and reducing side effects. This determination can be carried out using immunoassays or chromatographic procedures. Immunoassays are used in routine exams because they allow a quick and accurate assessment of drug concentration. On the other hand, chromatographic methods are more expensive and time consuming process but have the advantage of detecting and quantifying multiple drugs simultaneously in addition to examining their metabolites.
Epilepsy is a condition which affects the nervous system, characterized by unpredictable seizures, with or without associated convulsions. Currently it is known that epilepsy seizures are caused by abnormal discharges in the electrical activity of the brain and that it affects more than fifty million people around the world. Epilepsy treatment involves the use of antiepileptic and anticonvulsant drugs. The choice of drug therapy should be made according to the type of seizure, efficacy and adverse effects and the goal of therapy is to control seizures without causing side effects. There are several antiepileptic drugs available in the market, which are divided into classical and new antiepileptics. The classic drugs have high pharmacokinetic variability, narrow therapeutic range and significant adverse effects and drug interactions. On the other hand, the newer antiepileptic drugs, have better safety profiles, larger therapeutic range, better tolerability and alower pharmacokinetic variability and fewer drug interactions. Due to the intrinsic characteristics of these drugs, namely those regarding interactions with other drugs and the narrow therapeutic windows, its is necessary to perform its therapeutic monitoring whose main purpose is to individualize dosage. Thus, quantification of the concentration of a drug in a biological sample and can ensure an individualized therapy by increasing effectiveness and reducing side effects. This determination can be carried out using immunoassays or chromatographic procedures. Immunoassays are used in routine exams because they allow a quick and accurate assessment of drug concentration. On the other hand, chromatographic methods are more expensive and time consuming process but have the advantage of detecting and quantifying multiple drugs simultaneously in addition to examining their metabolites.
Description
Keywords
Epilepsia Fármacos antiepiléticos Carbamazepina Carbamazepina-10,11-epóxido Oxcarbazepina Monitorização terapêutica Métodos de quantificação Imunoensaios Métodos cromatográficos Epilepsy Antiepileptic drugs Carbamazepine Carbamazepine-10,11-epoxide Oxcarbazepine Therapeutic drug monitoring Analytical techniques Immunoassays Chromatographic techniques