Introduction: Methylphenidate hydrochloride (MPH, Ritalin®) – a dopaminergic and noradrenergic drug – is used to treat the attention-deficit/hyper activity disorder (ADHD) in children and adults as a first-line drug. Nevertheless, there are a few studies regarding the hematological changing following the chronic methylphenidate treatment. This study aimed to investigate hematological effects subsequent to the chronic methylphenidate treatment and its gender differences.
Methods: Forty male and female Wistar albino rats (aged 2–3 month) were randomly and equally divided into eight groups based on gender; six groups for treatment and two groups for control. Animals underwent 0.6, 2.5 or 10 mg/kg Ritalin or 0.9 saline (control) per day which were administered by gavage for 30 days. After the last administration, the blood samples were taken and evaluated for some main hematological parameters including a total count of red blood cell (RBC), white blood cell (WBC) and its differential and platelets.
Results: The average WBC count were significantly decreased at all doses in female rats while this reduction was in the middle and high dose (not low dose) in males in comparison to their baseline range (P<0.05). Furthermore, the reduction in females was more observable rather than their males counterparts. Meanwhile, there were no significant changes in the number of RBC, WBC differential or platelets from baseline range.
Conclusion: Our study suggested that chronic MPH may lead to Leukopenia in a dose and sex dependent manner. Leukopenia is presumably due to whether bone marrow suppression or some changes in the neuroendocrine system. It is worth mentioning that methylphenidate in females may has more impairing effect on leukocytes.