Methylphenidate

Methylphenidate
INN
Drug class	Stimulant; Norepinephrine–dopamine reuptake inhibitor (NDRI)
Routes of administration	By mouth, transdermal, insufflation, sublingual, rectal, intravenous
Pregnancy category
Bioavailability	Insufflation: ~70% Oral: ~30% (range: 11–52%)
Metabolism	Liver (80%) mostly CES1-mediated
Elimination half-life	2–3 hours
Excretion	Urine (90%)
Legal status
CAS Number	20748-11-2
PubChem	4158
DrugBank	DB00422
ChemSpider	4015
KEGG	D04999

Introduction

Methylphenidate is a central nervous system stimulant used for the therapy of attention deficit disorder and narcolepsy. 

Methylphenidate-stereoisomers_2D-skeletal

Liver safety

Methylphenidate has been linked to a low rate of serum aminotransferase elevations during therapy and to rare instances of acute, clinically apparent liver injury, generally after its intravenous abuse.

Mechanism of action

Methylphenidate (meth" il fen' i date) is a piperidine derivative that is structurally related to amphetamine which acts as a central nervous system (CNS) sympathomimetic stimulant, probably by causing release of norepinephrine at CNS nerve terminals promoting neurotransmission.  Methylphenidate may also affect dopaminergic neurotransmission.  Therapy with methylphenidate has been shown to increase cognitive abilities and improve psychological functioning and performance in children and adults with suspected attention deficit disorders.  It has a paradoxical calming action in children with hyperactivity.  Methylphenidate is also used in the therapy of narcolepsy. 

FDA approval information for Methylphenidate

Methylphenidate was initially approved for use in the United States in 1955 and its indications have been broadened to include children above the age of 6 and adolescents with attention deficit disorder.  Methylphenidate is available in multiple forms for oral administration including capsules, tablets, oral solutions and as extended release and long acting forms in concentrations varying from 2.5 to 54 mg in generic forms and under several brand names including Ritalin, Concerta and Metadate.  Transdermal formulations are also available. 

Dosage and administration for Methylphenidate

The usual dose in adults is 10 mg two or three times daily and average maintenance dosage is 40 to 60 mg daily.  The dosage in children varies by formulation.  Methylphenidate is a controlled substance (Schedule II) and has abuse potential. 

Side effects of Methylphenidate

Common side effects include headache, insomnia, irritability, palpitations, tachycardia, nasal stuffiness, decreased appetite, cough and rash.

The following are CNS stimulants

• Amphetamines (including ecstasy or methylenedioxymetamphetamine)
• Armodafinil
• Atomoxetine
• Cocaine
• Methylphenidate
• Modafinil

• Dailymed label info on Methylphenidate
• FDA Methylphenidate