Related Experiment Videos
Differential effects of methylphenidate on the growth of neonatal and adolescent rats
W J Pizzi1, E C Rode, J E Barnhart
1Department of Psychology, Northeastern Illinois University, Chicago 60625.
Insights
Methylphenidate (MPH) may temporarily stunt growth in young rats, but growth rebounds after treatment stops. Periadolescent rats showed no growth impairment, suggesting low risk for human stature with minimal therapeutic doses.
Area of Science:
- Pharmacology
- Developmental Biology
- Pediatrics
Background:
- Methylphenidate (MPH) is a primary treatment for Attention Deficit Disorders with Hyperactivity (ADD/H).
- Concerns exist regarding MPH's potential to inhibit growth in developing individuals.
- Previous studies indicated MPH causes acute growth impairment and rebound in neonatal rats.
Purpose of the Study:
- To confirm and extend findings on MPH's growth-suppressing effects in rats.
- To investigate MPH's impact on growth during the periadolescent developmental stage.
- To assess the reversibility and long-term implications of MPH-induced growth changes.
Main Methods:
- Neonatal and periadolescent male and female rats were treated with varying doses of MPH.
- Growth parameters were monitored following MPH administration and discontinuation.
- Comparative analysis between neonatal and periadolescent treatment groups was performed.
Main Results:
- Neonatal rats treated with MPH exhibited confirmed growth impairment and subsequent growth rebound.
- Rats treated during the periadolescent period did not display any significant growth impairment.
- These findings suggest MPH's growth-suppressing effects are acute and reversible.
Conclusions:
- The growth-suppressing effects of Methylphenidate appear to be due to acute toxicity that is reversible upon drug cessation.
- Treatment during the periadolescent period did not result in growth impairment in rats.
- There is a low probability of long-term effects on human body stature with minimal therapeutic MPH doses.
Abstract:
Methylphenidate (MPH), the drug of choice in the treatment of Attention Deficit Disorders with Hyperactivity (ADD/H), has raised concern regarding its suspected potential for reducing body stature in growing patients. In a previous study we demonstrated that neonatal rats treated with MPH (35 mg/kg, SC, twice daily) showed an acute growth impairment followed by a rapid growth-rebound phenomenon. This report confirms our earlier findings in neonatal rats and extends the investigation of the growth suppressing effects of MPH to the periadolescent period of development in rats. Specifically, neonatal groups of male and female rats treated with higher and lower doses of MPH than in the original study confirmed the growth impairment and growth rebound phenomena reported earlier. Unlike neonatal rats, rats treated during the periadolescent period of development failed to show any growth impairment. These data suggest that the growth suppressing effects of MPH are the result of an acute toxicity which is readily reversible on discontinuation of the drug. Further, it is concluded that there is a low probability of long term effects on human body stature when the minimal therapeutic dose is used in clinical practice.