Detection of the analgesic effect of ceftriaxone in chicks

Objective: To evaluate the analgesic effect of ceftriaxone when administered alone or in combination with paracetamol and diclofenac sodium in boiler chicks. Methods: This study was conducted in Department of Physiology, Biochemistry and Pharmacology, College of Veterinary Medicine ,University of Mosul , Mosul, Iraq, from November 2021 to February 2022. It was determined using formaldehyde test and the median analgesic effective dose (ED 50 ) for ceftriaxone, paracetamol and diclofenac sodium depending on the method of Dixon. An isobolographic ratio of 0.5:0.5 of the ED 50 for each drug at the analgesic level was calculated. Results: The administration of ceftriaxone at doses of (523, 1064 and 1330mg/kg) intramuscularly was led to a significant (p value=0.02) and clear analgesic effect through the disappearance of the right foot lift caused by the injection of formaldehyde, in aadition to significant decrease (p value=0.01) in foot thickness at dose of 1330 mg/kg . Analgesic ED 50 of ceftriaxone , paracetamol and diclofenac sodium by Dixon method were 42.6 ,32.6 and 6.26 mg /kg respectively. The intramuscular administrations of drugs in a ratio of 0.5:0.5 result in a significant decrease (p value<0.001) in ED 50 values to 6.77, 5.34 and 0.99 mg/kg respectively. The application of the isobolographic analysis revealed the type of interaction between ceftriaxone/paracetamol, ceftriaxone /diclofenac sodium, and the interaction was synergistic when they were given at the ratio 0.5:0.5. Conclusion: The results showed that ceftriaxone exerts its analgesic effect in chicks by reducing the mechanical hyperalgesia resulting from formaldehyde injection in the planter of the right foot and potentiated the analgesic effects of paracetamol and diclofenac sodium through the synergistic interaction.