Abstract
Background:
Euthanasia is a difficult ethical choice with many interrelated components, and a thorough treatment of the topic is outside this document’s purview.

Aim:
This study aimed to test the possibility of using either tilmicosin or suxamethonium to evaluate the time required for experimentally induced smooth comfortable euthanasia in dogs.

Method:
Six adult dogs of both sexes, their weight (20±5kg) and age (24±6 months) were included in this experiment. The experiment randomly divided into two equal groups. The general anesthetic regime used in this experiment included a mixture of ketamine and xylazine. The data relied on clinical findings and electrocardiography (ECG) tool to record changes exhibits on experimental dogs to perform comfortable, painless euthanasia

Results:
The results indicated that the time required to induce euthanasia varied between the two groups. In the Suxamethonium group (SG) it took around 1-12 minutes with clinical findings manifested by the absence of neurological convulsions or muscle contractions and respiratory arrest with cyanosis of the mucous membranes without epilepsy. In the tilmococin group (TG) it took around 1-4 minutes, and the clinical findings were manifested by the presence of severe neurological convulsions for a short period. In the SG group, ECG abnormalities, such as prolonged QT intervals or even arrhythmias, sinus bradycardia, and absence of electrical activity, were observed. In contrast, in the TG group, there were significant concern alterations in ECG, represented by prolonged QT intervals, duration of ventricular depolarization and repolarization, ventricular fibrillation, and sudden death.

Conclusion:
Both suxamethonium and tilmicosin are viable agents for inducing euthanasia in dogs; however, suxamethonium demonstrated superior efficacy and safety, facilitating euthanasia with minimal complications.

Key words: Tilmicosin; Suxamethonium; Euthanasia; ECG; Canine.