| Methylphenidate |
CNS Stimulant
Methylphenidate is a mild CNS stimulant.
The mode of action in man is not completely understood, but methylphenidate presumably activates the brain stem arousal system and cortex to produce its stimulant effect.
There is neither specific evidence which clearly establishes the mechanism whereby methylphenidate produces its mental and behavioral effects in children, nor conclusive evidence regarding how these effects relate to the condition of the CNS.
Methylphenidate is rapidly and extensively absorbed from the tablets following oral administration; however, owing to extensive first-pass metabolism, bioavailability is low (approx. 30%) and large individual differences exist (11 to 52%).
Peak plasma concentrations of 10.8 and 7.8 ng/mL were observed, on average, 2 hours after administration of 0.30 mg/kg in children and adults, respectively.
mean half-life of 2.4 hours in children and 2.1 hours in adults.
Following oral administration of methylphenidate, 78 to 97% of the dose is excreted in the urine and 1 to 3% in the feces in the form of metabolites within 48 to 96 hours.
Methylphenidate and its metabolites exhibit low plasma protein binding (approx. 15%).
Methylphenidate in the extended-release tablets is more slowly but as extensively absorbed as in the regular tablets.
