Amitraz: pharmacological and toxicological aspects in animals

Infestations by ectoparasites are one of the greatest problems in the veterinary practice, due to a large drop in performance in cattle herds and other farm animals, generating great economical losses; for pets, besides the low quality of life and disruption of homeostasis, ectoparasites represent a risk for transmission of zoonotic diseases. The formamidines emerge as a very large group of ectoparasiticides, which its main representative, amitraz, is the only one approved for animal use. Amitraz is indicated for animal use against mites, lice, and ticks for cattle, swine, and sheep. For dogs, it is used against ticks and mites. However, due to a lack of proper orientation and information, reports of accidental intoxications by amitraz, in both animals and humans, are not unusual in the literature. Amitraz intoxication has been reported in dogs, and the clinical signs are evidenced in the nervous, digestive, cardiovascular, and urinary systems and include sedation, bradycardia, bradyarrhythmias, hypotension, bradypnea, transitory hyperglycemia, mydryasis, and hypothermia, cats being more sensitive than dogs regarding these last signs. To detect amitraz and its main metabolites, there are many standardized methodologies. This review describes the pharmacokinetics, pharmacodinamics, indications, toxicological and pathological effects of amitraz, as well as the intoxication treatment and the aspects related to its detection in biological matrices.