Methylphenidate (MPH) is a mild central nervous system stimulant and has been a common drug used for treating attention deficit hyperactivity disorder (ADHD) for numerous years. MPH inhibits re-uptake of dopamine into the pre-synaptic nerve by blocking the dopamine transporter, leading to an increase in dopamine within the synapse and further stimulation of the dopamine receptors on the post-synaptic nerve. In patients with ADHD this has a beneficial effect on behaviour, cognition, short-term memory, reaction time, vigilance and learning. MPH is currently available in a range of dosage forms from oral controlled or immediate release formulations through to Daytrana™ a controlled release transdermal matrix patch.