ELECTROCARDIOGRAPHIC STUDY IN DOGS GIVEN AMITRAZ INTRAVENOUSLY.

A. FARIAS, C. A. A. VALADÃO, N. OLESKOVICZ

Abstract


Amitraz is a widely used alpha-two agonist insecticide and acaricide formamidine that is very effective to control ectoparasites. This drug can promote dose-dependent changes in cardiovascular parameters, such as bradycardia, first and second-degree atrioventricular block, decreased cardiac output, hypertension, and hypotension. Therefore, the aimof this research was to evaluate the possible electrocardiographic changes in dogs receiving an intravenous injection of amitraz. Eleven healthy mongrel mature dogs of either sex were used. They were given amitraz 1mg.kg-1 by intravenous route. Electrocardiography was recorded immediately before (baseline level) and then at 1, 5, 10, 20, 30, 40, 50, and 60 minutes after the drug administration. A paired t test was used to analyze data at a significance level of 5% (p<0.05). According to results, amitraz decreased the duration of P wave, and increased QT, PT, and RR intervals. The QRS complex remained unchanged, and a severe bradycardia was observed. It is possible to assume that amitraz produced typical alphatwo agonist cardiovascular effects, leading to bradycardia, although neither first nor second-degree atrioventricular block
were observed.
KEY -WORDS: ECG. Amitraz. Dogs.



DOI: http://dx.doi.org/10.15361/2175-0106.2005v21n4p109-115