Purpose: The recent ceftriaxone-induced anaemia and mortalities at the dose of 50 mg/kg in Veterinary Teaching Hospital, University of Nigeria prompted this study which sought to assess the clinicotoxicological effects of ceftriaxone (CFZ) after intramuscular administration of graded doses in Basenji dogs.Methods: The effects of CFZ on the haematological indices, physiological parameters, liver and kidney functions were assessed in 4 group of dogs (n = 4) designated A – D. They were given CFZ intramuscularly for 21 days at doses of 12, 25 and 50 mg/kg for groups A, B, C, respectively, while thecontrol (group D) received the diluent (lignocaine 0.2 mL)Results: The mean pulse and heart rate of dogs in group C were significantly (p < 0.05) higher than those of group A, B and D. Significant (p < 0.05) decrease in red blood cell count (RBC), haemoglobin concentration (Hb) and packed cell volume (PCV) was observed in group C on days 7 and 14, while on day 21, these parameters were significantly (p < 0.05) higher in group D than in the treated groups. On day 14 of CFZ administration, the alanine transaminase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities of dogs in group C was significantly (p < 0.05) elevated than the control group.Conclusion: These findings suggest that CFZ, at the doses of 12.5 - 25 mg/kg, appears safe in dogs as most of the adverse effects observed are reversed following the withdrawal of the drug on day 28. However, CFZ at 50 mg/kg causes anaemia, tachycardia and bilateral paralysis of the hind limbs which did not revert to normal after one week; hence, it is not recommended for use in dogs at this dose
