Use of high doses of pimobendan in animals with dilated cardiomyopathy.

Abstract

In veterinary practice, drugs containing pimobendan are often used to treat cardiac patients. This is due to the positive ionotropic and vasodilating effect of pimobendan. For service dogs with dilated cardiomyopathy (DCM), increasing the ionotropic effect is of particular importance. It was assumed that increasing the dosage of pimobendan will increase the ejection fraction (EF) and fractional shortering (FS) in animals with DCM, that is, an increase in heart rate. The study of these indicators was carried out using echocardiography using the Simpson disc method. In the instructions for using the drug, it is noted that the daily dose of pimobendan is 0.5 mg per 1 kg of animal body weight. A clinical study was conducted in which a high dosage of pimobendan was used - 1 mg per 1 kg of animal body weight. The drug was used in oral form. The study involved 236 dogs. The study found that the use of high doses of pimobendan did not cause a pronounced positive effect, compared with the normal dosage of the active substance. Thus, FS relative to the initial level for animals taking 1 mg of pimobendan per 1 kg of body weight showed an increase by 10.3%, an increase in EF by 8.9%. In animals that received 0.5 mg of pimobendan per kg of body weight, FS increased 9.9% and EF increased 8.3%. The mean FS difference between animals taking 0.5 mg per kg of body weight and animals taking 1 mg of pimobendan per kg of body weight was only 0.4%, and the difference in EF was 0.6%, respectively. Among the side effects of high dosage of pimobendan were identified: nausea and vomiting in 3% of the dogs studied, tachycardia in 4% of the animals, and a decrease in blood pressure in 1% of dogs. However, some side effects have been reported in dogs treated with 0.5 mg pimobendan per kg body weight. Among them: vomiting and nausea in 1% of the studied dogs, tachycardia in 1% of animals. Based on the results of the study, we can conclude that the use of pimobendan gives an increase in FS by 9.9% and EF by 8.3%. Increasing the dosage of pimobendan by 2 times does not give a significant increase in the studied parameters.