Background: Methylphenidate or ritalin is one of the brain stimulant drug and used in treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy and situational tachycardia syndrome. In the present survey, the effect of methylphenidate on the liver was studied.

Materials and methods: In this experimental study, a total of 24 male mice were randomly divided into three groups, including one control and two experimental groups. In experimental groups, ritalin was used in the doses of 2 and 10 mg/kg by gavages method for 40 days. At the end of the period and after animals’ euthanasia, the livers specimens were removed. Then, histological changes were studied using a light microscope. Also, blood sera were collected and the hepatic enzymes activity was determined. The data were statistically analyzed by ANOVA test and the p<0.05 was considered as significant.

Results: Administration of methylphenidate in different concentrations resulted in significant reduction of hepatocytes diameters, decrease in nuclei diameters, increase in the size of hepatic sinusoids, and also necrosis and congestion in central vein. Furthermore, in the liver parenchyma belonging to treated groups, the infiltration of mononuclear leukocytes was observed. In the treated groups, the activity of the hepatic enzymes showed a significant increase compared with the control group.

Conclusion: Considering the present findings, it could be suggested to avoid of prescribing of methylphenidate, especially in the patients with hepatic failures.

Keywords: Methylphenidate, Enzyme, Liver, Mouse.