This study evaluated the systemic effects of metamizole with or without general anesthesia in healthy dogs. Twelve mixed healthy dogs of either sex were divided randomly into two groups (control and anesthesia groups).Following a 12-h period of fasting (food and water), both groups received the first dose of metamizole (35 mg/kg) intravenously and then 4 doses intramuscularly every 12 h after receiving the first dose of metamizole. In the anesthesia group, the animals underwent halothane inhalation anesthesia for 2 h after receiving the first dose of metamizole. The vital signs were monitored but animals did not receive any fluid during anesthesia. Blood samples were taken before fasting, after 12 h of fasting and then 24 and 48 h after the first dose of metamizole for evaluation of CBC, blood urea nitrogen, and serum creatinine. Mucosal bleeding times (MBTs) and bone marrow samples were evaluated prior to the start of the study and after the last dose of metamizole in both groups. The total number of red blood cells, PCV, and BUN values showed a significant increase 12 h after fasting compared with baseline values in both groups. There were no significant differences in bleeding times or bone marrow function compared to baseline in either group. It was concluded that short-term use of metamizole, starting before surgery and anesthesia in normal dogs that have not received fluids, does not have adverse effects on renal, coagulation, blood, and bone marrow functions.

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