Metronidazole-induced toxicosis in dog – case report Intoxica o por metronidazol em c o – relato de caso

Metronidazole is a nitronidazolic antibiotic used in veterinary medicine to the treatment of a variety of diseases. The cause of metronidazole neurotoxicity has not been determined. We report the case of a dog, female, Teckel, five-year-old, with a history of dorsiflexion of the tail, ataxia, muscle stiffness, recumbency, vertical nystagmus, apathy and anorexia, which was being medicated for seven days with metronidazole in a dose higher than the maximum recommended, and the neurological signs began after this period. Neurological signs were consistent with central vestibular dysfunction caused by metronidazole, such as ataxia and vertical nystagmus. In addition to the neurological changes, the clinical signs of anorexia and apathy are consistent with the administration of excessive doses of the medicine. The diagnosis of metronidazole-induced toxicosis is based on the history of normal to increased doses, clinical signs and resolution after discontinuation of the drug. In general, the prognosis is good after drug withdrawal and early diagnosis. Some dogs may die and others may recover completely. The neurotoxicosis has disappeared after the suspension of the medicine and supportive treatment. Veterinarians must be aware of potential complications associated with the use of this medicine, as well as limit their chronic use or high doses for the most severe cases, and diagnose the problem as quickly as possible to institute an early treatment. O metronidazol é um antibiótico nitronidazólico usado na medicina veterinária para o tratamento de uma variedade de doen as. A causa da neurotoxicidade pelo metronidazol ainda n o foi determinada. Relata-se o caso de um c o, fêmea, da ra a Teckel, de cinco anos de idade, com histórico de dorsoflex o da cauda, ataxia, rigidez de musculatura, decúbito, nistagmo vertical, apatia e anorexia, que estava sendo medicada há sete dias com metronidazol em dose maior que a máxima recomendada, sendo que os sinais neurológicos iniciaram-se após esse período. As altera es neurológicas foram compatíveis com disfun o vestibular central causada pelo metronidazol, tais como ataxia e nistagmo vertical. Além das altera es neurológicas, o quadro de anorexia e apatia é condizente com a administra o de doses excessivas do fármaco. O diagnóstico da intoxica o por metronidazol é baseado na história de administra o de doses normais a aumentadas, nos sinais clínicos e na resolu o destes após a suspens o da droga. Geralmente, o prognóstico é favorável após a suspens o do medicamento e com o diagnóstico precoce. Alguns c es podem morrer