Background: Trimethoprim is considered as a trimethoxy benzyl pyrimidine, the action mechanism of which is to block the synthesis of tetrahydrifolate. Sulfamethoxazole is an antibacterial drug from the sulfanamide group, this drug prevents from synthesis of dihydrofolic acid. Trimethoprim which is consumed along with sulfonamide controls the metabolic oxidants which in turn increases the anti microbial effect of each drug. In this research the effects of cotrimoxazole on the biochemical blood factors in adults male rats were studied.

Materials and Methods: The animals used in the experiment were 50 male wistar rats each weighting 250 grams. The rats were divided into 5 groups of 10 randomly. The control group, the sham group receiving propylene glycol solution. Three experimenal groups received cotrimoxazole of 30, 60 and 120 mg/kg dosage. The drug injected oral for 14 days. After 14 days, blood samples were taken. Biochemical blood factors( FBS, BUN,TG, Cholestrol, Uric acid,Creatinine) were measured. The results of this study were analyzed using appropriate statistical programs sach as SPSS and the Tukey, ANOVA and T- test.

Results: Statistical analysis of results showed that concentration of creatinine increased significantly in experimental groups receiving 60 and 120 mg/kg dosage in comparison with the sham and control groups. Also, all groups receiving cotrimoxazole showed a significant increase in BUN concentration in comparison with to the control and sham groups. All groups receiving cotrimoxazole showed significant reduce in TG concentration compared with the control and sham groups. The group receiving cotrimoxazole of 120 mg/kg dosage showed a significant increase in cholesterol concentration compared with the control and sham groups. All groups receiving cotrimoxazole showed no significant difference in FBS and uric acid compared with the control and sham groups ( p <0.05).

Conclusion: Likely cotrimoxazole increases cholesterol concentration which probably due to thyroid hormones decrease and cholesterol liver reabsorption. Cotrimoxazole increases creatinine concentration probably due to inhibited creatinine tubular secretion. Cotrimonazole increases BUN concentration probably due to liver failure induced by the drug.