Toxicological evaluation of long-term intravenous administration of amitraz in horses

Abstract

With the aim of determining the possible toxicity of amitraz after its prolonged use in horses, six English Thoroughbred horses received intravenous injections of amitraz (0.05, 0.10 or 0.15 mg/kg) weekly for four months, constituting the experimental group. Eight other animals (control group), via the same route following the same drug administration schedule and period of time, received the vehicle, dimethylformamide. At the end of this period, blood was collected from all the animals, and a comparison was made of the means of the values obtained for the various blood analyses: complete hemogram, alkaline phosphatase, gamma-glutamyltransferase, blood urea nitrogen, lactate dehydrogenase, aspartate aminotransferase, creatine phosphokinase, glucose, albumin, total protein, creatinine, Na+ , K+, Cl- and CO2. The results for the biochemical characteristics showed that only the mean value for urea of the animals submitted to treatment with amitraz was significantly different than the mean value obtained for the control group. The analyses of the hematological characteristics showed that no significant differences between groups were observed. Similarly, the measurement of blood electrolyte levels demonstrated that long-term treatment with amitraz did not cause significant changes in the variables analyzed. The results indicate that amitraz, given in the doses employed in this study, did not show signs of inducing toxic effects in vital organs, even after prolonged administration.

Hypoglycaemia management with a hypercaloric supplementation in neonatal puppies delivered by caesarean section

“…Hypoglycaemia treatment protocol usually consists in using 10% glucose, and the empirical use of glucose is discouraged since it can cause a hyperglycaemia-induced condition (Mila et al, 2017;Uchańska et al, 2022;Wilborn, 2018). Nutraceuticals can also be used to prevent diseases and malnutrition without causing harm to animal health when properly prescribed (Queiroz-Neto et al, 2012).…”

“…Hypoglycaemia treatment protocol usually consists in using 10% glucose, and the empirical use of glucose is discouraged since it can cause a hyperglycaemia‐induced condition (Mila et al, 2017; Pereira & Lourenço, 2022; Uchańska et al, 2022; Wilborn, 2018). Nutraceuticals can also be used to prevent diseases and malnutrition without causing harm to animal health when properly prescribed (Queiroz‐Neto et al, 2012). The use of hypercaloric supplements to treat hypoglycaemia in newborns puppies has not yet been described in the literature; however, the use of milk substitutes as an energy supplement containing vitamins, minerals, amino acids and maltodextrin has been described already, and it has demonstrated a decrease in the risk of neonatal death and an increase in the puppy's initial growth rate (Mila et al, 2016).…”

Comparação dos efeitos da romifidina e de uma emulsão de amitraz na sedação e na atividade locomotora espontânea de eqüinos

“…9,10,11 Amitraz showed central effects of alpha-2 adrenoceptor agonist, inducing similar ataxia, intestinal stasis, behavioral, cardiovascular, muscular and diuretic effects. 12,13,14,15,16,17 These effects could provide an indication for the use of amitraz for sedation practices in veterinary medicine, and this might be particularly appealing in horses because of its low price and its potential analgesic and muscle relaxing effects. 18 Considering the well known effects of romifidine on horses, mediated by its highly specific action on alpha-2 adrenoceptors, this behavioral study proposes to compare its sedative effects with those induced by an emulsion of amitraz, in order to determine the possibility of using this drug as a sedative for horses.…”