Abstract
The present study was designed to compare between the effect of tramadol Hcl and fentanyl citrate on some hematological and serum biochemical parameters in dogs. For this purpose, ten adult mongrel dogs were randomly allocated into two equal groups: Group ɪ; dogs received tramadol hydrochloride 2 mg kg-1 IV; Group ɪɪ; dogs received fentanyl citrate 5 µg kg-1 IV. The measured hematological variables were: red blood cell count, packed cell volume, hemoglobin concentration, total leucocytic count, differential leucocytic counts and platelet count. Serum samples were assessed for concentrations of total protein, albumin, glucose, urea, creatinine and serum enzymatic activities of alanine and aspartate transaminases. All parameters were recorded at baseline, following administration of analgesic agents (0 time) and for 1.5 hour later at 15 minutes interval. Data were analyzed using a paired- samples t-test (p < 0.05). As a result, tramadol induced a significant (p < 0.05) decrease in total leukocytic and neutrophil counts while, a significant (p < 0.05) increase in total leucocytic, lymphocyte and neutrophil counts were recorded at some time periods in fentanyl group. Blood platelets significantly increased in both groups. Serum urea levels significantly increased in tramadol group while, in fentanyl group, at some periods it showed a significant (p < 0.05) decrease as well as creatinine. Red cell parameters as well as other serum biochemical parameters did not show any significant changes in both group. It was concluded that, Fentanyl might have some virtues on leukogarm and some biochemical parameters in dogs. Subsequently, its use may be advantageous over tramadol for canine patient suffering from leukopenia and renal disorders.

Key words: tramadol, fentanyl, hematological, biochemical, dogs