Methylphenidate

Methylphenidate (MPH; MPD) is a psychostimulant drug approved for treatment of ADHD or attention-deficit hyperactivity disorder, postural orthostatic tachycardia syndrome and narcolepsy. It is better known by its 1948 trademarked name of Ritalin (original owner CIBA, now Novartis Corporation), was first licensed by the FDA in 1955 for treating ADHD, prescribed from 1960, and became heavily prescribed in the 1990s, when ADHD itself became more widely accepted.

ADHD and some other conditions are believed to be linked to sub-performance of the dopamine, norepinephrine, serotonin and glutamate processes in the brain responsible for self-regulation functions, leading to self-regulation disorders compromising the sufferer's attention, self-control, behaviour, motivation, and executive function; methylphenidate primarily works by reducing the reuptake (removal) of dopamine and norepinephrine (and to a lesser extent serotonin) which improves the levels and utility of these neurotransmitters in the brain.

Methylphenidate may also be prescribed for off-label use in treatment-resistant cases of lethargy, depression, and obesity. Methylphenidate incorporates a phenethylamine skeleton within its molecular structure, and increases the levels of dopamine and norepinephrine in the brain through reuptake inhibition of the respective monoamine transporters. Methylphenidate also possesses some structural and pharmacological similarities to cocaine, though MPH is less potent and longer in duration.

Methylphenidate is produced in the United States, Mexico, Spain and Pakistan. Other brands include Concerta, Methylin, and Daytrana, and generic forms, including Methylin, Metadate and Attenta are produced by numerous pharmaceutical companies throughout the world. Ritalin is also sold in Canada, Australia, the United Kingdom, Spain, Germany, Israel and other European countries (although in much lower volumes than in the United States). In Belgium the product is sold under the name Rilatine and in Brazil, Portugal and Argentina as Ritalina. In Thailand, it is found under the name Hynidate.

On occasion, treatment emergent psychosis can occur during long-term therapy with methylphenidate; regular psychiatric monitoring of people who are taking methylphenidate for adverse effects such as psychotic symptomatology (with regard to the need for dose adjustment or discontinuation of medication) has been recommended. People with ADHD have an increased risk of substance abuse, and stimulant medications reduce this risk. In the majority of unremarkable isolated cases MPH overdose is asymptomatic (symptomless) or only incurs minor symptoms even in children under age 6, is only rarely severe, and normally any abreaction will show within 3 hours, however injection (particularly arterial) has sometimes led to toxic necrosis and amputation at the point of injection, and emergency treatment is also recommended beyond certain overdose levels and also in cases of self-harm or monoamine oxidase inhibitor (MAOI) use.