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A importância dos antibióticos aminoglicosídeos e os seus efeitos adversos
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Abstract(s)
Waksman obteve a primeira molécula de aminoglicosídeos, a estreptomicina, em 1944, o que a torna pertencente a uma das classes mais antigas de antibióticos. Outras moléculas semelhantes, produzidas por microorganismos e/ou por processos semissintéticos, surgem nos anos seguintes. Na prática clínica atual, salientam-se cinco antibióticos que pertencem a esta classe: estreptomicina, tobramicina, gentamicina, netilmicina e amicacina.
Os aminoglicosídeos, antibióticos constituídos por dois ou mais açúcares aminados unidos a um anel aminociclitol através de ligações glicosídicas, apresentando um grande número de radicais NH2 e OH, caracteriza-se pela sua natureza policatiónica. Embora detenham um grande espectro de ação, apresentem grande atividade para bactérias aeróbias de Gram negativo e atividade moderada contra bactérias aeróbias de Gram positivo, o mesmo não sucede contra bactérias anaeróbias estritas.
Esta classe de antibióticos apresenta um grande espectro de ação antibacteriana e faz ligação ao ribossoma bacteriano, tendo como vantagens terapêuticas a sua atividade bactericida, sinergismo com outros antibióticos, especialmente β-lactâmicos, o seu efeito pós-antibiótico e uma farmacocinética consideravelmente previsível.
Ainda assim, os aminoglicosídeos também são caracterizados pelo seu potencial de toxicidade. A ototoxicidade evidencia-se pela facilidade que estes têm em causar danos a nível vestibular e/ou coclear irreversível. A nefrotoxicidade, por seu lado, é dose dependente e, por norma, reversível.
Para aumentar a probabilidade do sucesso terapêutico é fundamental a redução da ocorrência dos efeitos tóxicos relacionados com os aminoglicosídeos, assim como realização de estudos para compreensão dos distintos parâmetros farmacocinéticos.
Waksman obtained the first aminoglycosides molecule, streptomycin, in 1944, that makes it part of one of the oldest classes of antibiotics. Other similar molecules, produced by microorganisms or by semi-synthetic processes, emerge in the following years. In nowadays clinical practice, five of this antibiotics class are pointed out: streptomycin, tobramycin, gentamicin, netilmicin and amikacin. Aminoglycosides, antibiotics composed by two or more amino sugars attached to an aminocyclitol ring through glycosidic bonds, presenting a large number of NH2 and OH radicals, are characterized by its polycationic nature. Although they exhibit a broad spectrum of action, show great activity on Gram negative aerobic bacteria and moderate activity against Gram positive aerobic bacteria, the same doesn’t happen against strict anaerobic bacteria. This antibiotics class presents a great spectrum of antibacterial action and binds to the bacterial ribosome, having as therapeutical advantages its bactericidal activity, antibiotics synergism, namely β-lactams, its post-antibiotics effect and a considerably predictable pharmacokinetics. Nevertheless, aminoglycosides are also characterized by their toxicity potencial. Ototoxicity is shown by its ability to cause irreversible damage at a vestibular and/or cochlear level. Nephrotoxicity, on the other hand, is dose dependent and, by default, reversible. In order to increase therapeutical success probability, is central the reduction of aminoglycosides related toxic effects occurrence, as well as conducting studies in order to understand the distinct pharmacokinetic parameters.
Waksman obtained the first aminoglycosides molecule, streptomycin, in 1944, that makes it part of one of the oldest classes of antibiotics. Other similar molecules, produced by microorganisms or by semi-synthetic processes, emerge in the following years. In nowadays clinical practice, five of this antibiotics class are pointed out: streptomycin, tobramycin, gentamicin, netilmicin and amikacin. Aminoglycosides, antibiotics composed by two or more amino sugars attached to an aminocyclitol ring through glycosidic bonds, presenting a large number of NH2 and OH radicals, are characterized by its polycationic nature. Although they exhibit a broad spectrum of action, show great activity on Gram negative aerobic bacteria and moderate activity against Gram positive aerobic bacteria, the same doesn’t happen against strict anaerobic bacteria. This antibiotics class presents a great spectrum of antibacterial action and binds to the bacterial ribosome, having as therapeutical advantages its bactericidal activity, antibiotics synergism, namely β-lactams, its post-antibiotics effect and a considerably predictable pharmacokinetics. Nevertheless, aminoglycosides are also characterized by their toxicity potencial. Ototoxicity is shown by its ability to cause irreversible damage at a vestibular and/or cochlear level. Nephrotoxicity, on the other hand, is dose dependent and, by default, reversible. In order to increase therapeutical success probability, is central the reduction of aminoglycosides related toxic effects occurrence, as well as conducting studies in order to understand the distinct pharmacokinetic parameters.
Description
Keywords
Aminoglicosídeos Antibióticos Bactérias de gram negativo Parâmetros farmacocinéticos Nefrotoxicidade Ototoxicidade Aminoglycosides Antibiotics Gram-negative bacteria Pharmacokinetics Nephrotoxicity Ototoxicity