Methylphenidate: Difference between revisions

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| pregnancy = Pregnancy categories were retired by FDA in 2015. Limited reproductive data with small observational signal for cardiac malformations; risk-benefit decision, with many patients deferring ADHD treatment during pregnancy. See pregnancy_details for the full discussion.

| legal = Schedule II

| intro = '''Methylphenidate''' is a piperidine-derivative central nervous system psychostimulant and the most widely prescribed med for attention-deficit hyperactivity disorder. First synthesized by Leandro Panizzon at Ciba in 1944 (and reportedly named "Ritalin" after his wife Rita, who used it), it has been clinically available since the mid-1950s. Mechanistically, methylphenidate is a pure norepinephrine–dopamine '''reuptake''' inhibitor, distinct from the amphetamines, which primarily ''release'' monoamines via reverse transport. This pharmacologic difference contributes to a somewhat smoother subjective profile and slightly lower abuse liability per milligram, though methylphenidate remains a Schedule II controlled substance with meaningful misuse potential. Multiple formulations exist (immediate-release, several extended-release oral preparations, a transdermal patch, and a chewable/liquid), allowing duration-of-action to be matched to clinical need.

| intro = '''Methylphenidate''' is a piperidine-derivative central nervous system psychostimulant and the most widely prescribed med for attention-deficit hyperactivity disorder. First synthesized by Leandro Panizzon at Ciba in 1944 (and reportedly named "Ritalin" after his wife Rita, who used it), it has been clinically available since the mid-1950s. Mechanistically, methylphenidate is a pure norepinephrine–dopamine '''reuptake''' inhibitor, distinct from the amphetamines, which primarily ''release'' monoamines via reverse transport. This pharmacologic difference contributes to a somewhat smoother subjective profile and slightly lower abuse liability per milligram, though methylphenidate remains a Schedule II controlled substance with meaningful misuse potential. Multiple formulations exist (immediate-release, several extended-release oral preparations, a transdermal patch, and a chewable/liquid), allowing duration-of-action to be matched to clinical need. A 2018 systematic review and network meta-analysis by Cortese and colleagues identified methylphenidate as first-line pharmacotherapy for ADHD in children and adolescents (based on the balance of efficacy and tolerability), with amphetamines as first-line in adults.<ref name="cortese2018">Cortese S, Adamo N, Del Giovane C, et al. Comparative efficacy and tolerability of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis. The Lancet Psychiatry. 2018;5(9):727–738.</ref>

| pharmacokinetics = '''Absorption:''' Rapid oral absorption; peak plasma levels in 1–2 hours for IR. Bioavailability is only ~30% due to extensive first-pass metabolism. Food modestly delays but does not significantly reduce absorption. The transdermal patch (Daytrana) bypasses first-pass and produces somewhat higher and steadier serum levels per dose. '''Distribution:''' Volume of distribution ~13 L/kg; plasma protein binding ~15%. Crosses the blood–brain barrier. '''Metabolism:''' Primarily metabolized by '''carboxylesterase 1 (CES1)''' in the liver, not by cytochrome P450 enzymes, to ritalinic acid, which is pharmacologically inactive. This metabolic route makes methylphenidate relatively free of CYP-mediated med interactions, distinguishing it from amphetamines. '''Stereochemistry:''' Methylphenidate has two stereocenters; the d-threo enantiomer carries essentially all pharmacologic activity. Dexmethylphenidate ([[Focalin]]) is the isolated d-threo enantiomer and is roughly twice as potent per milligram. '''Elimination:''' ~90% renally excreted as ritalinic acid; ~1% unchanged. Half-life of the parent compound is 2–3 hours, hence the need for extended-release formulations or multi-dose-daily schedules for sustained effect.

| history =

Methylphenidate emerged from a chemistry program at the Swiss pharmaceutical company Ciba AG (later Ciba-Geigy, then Novartis) in the 1940s. Leandro Panizzon, a chemist at Ciba, synthesized the compound in 1944 while searching for a stimulant with a less abrupt and less euphoric profile than amphetamine. Panizzon and his colleagues observed the stimulant effect in animals and ultimately on themselves; the canonical anecdote, widely repeated in pharmacology histories and Ciba/Novartis corporate retrospectives, is that Panizzon's wife Marguerite ("Rita") used the compound as a mild stimulant before tennis matches, which inspired the trade name Ritalin.{{citation needed}}

Ciba launched methylphenidate as Ritalin in Switzerland in 1954 and in the United States the following year, originally marketed for narcolepsy, chronic fatigue, mild depression, senile behavioral problems, and as an amphetamine-overdose antidote (this last use long since abandoned). Clinical application to childhood behavioral disorders developed gradually through the late 1950s and 1960s; the diagnosis then was "minimal brain dysfunction" or "hyperkinetic reaction of childhood," the precursors to the modern attention-deficit hyperactivity disorder formulation.{{citation needed}}

Methylphenidate was placed on Schedule II of the U.S. Controlled Substances Act in 1971, alongside amphetamine and cocaine, where it has remained.<ref name="csa-1971">U.S. Drug Enforcement Administration. Controlled Substances Act (21 U.S.C. §§ 801–971), Schedule II. 21 CFR 1308.12.</ref> The 1990s and 2000s saw a marked expansion of ADHD diagnosis and methylphenidate prescribing in the United States, accompanied by the development of extended-release formulations (Concerta osmotic-pump tablets approved 2000; Ritalin LA 2002; Metadate CD 2001; Daytrana transdermal patch 2006) that reduced the practical burden of multiple-times-daily dosing and supported broader adult use.

The largest independent comparative-effectiveness data source on methylphenidate is the Multimodal Treatment of ADHD (MTA) study, a National Institute of Mental Health-funded randomized controlled trial published in 1999 that compared medication management (predominantly methylphenidate), behavioral therapy, the combination of both, and community standard care in 579 children aged 7–9 with ADHD. The medication and combined arms produced significantly greater improvement in ADHD symptoms than the behavioral or community arms at 14 months.<ref name="mta1999">MTA Cooperative Group. A 14-month randomized clinical trial of treatment strategies for attention-deficit/hyperactivity disorder. Archives of General Psychiatry. 1999;56(12):1073–1086.</ref> Long-term follow-ups have moderated the short-term superiority finding, with diminishing between-group differences by 36 months and broadly comparable functional outcomes across arms by adulthood.{{citation needed}}

Cardiovascular safety in long-term outpatient use was characterized by Cooper and colleagues in a large 2011 cohort study published in the New England Journal of Medicine: among 1,200,438 children and young adults receiving ADHD medications, no significant association with serious cardiovascular events was found compared with non-users, after adjustment for cardiovascular risk factors.<ref name="cooper2011">Cooper WO, Habel LA, Sox CM, et al. ADHD drugs and serious cardiovascular events in children and young adults. New England Journal of Medicine. 2011;365(20):1896–1904.</ref> A companion JAMA study by Habel and colleagues reached similar conclusions in adults.<ref name="habel2011">Habel LA, Cooper WO, Sox CM, et al. ADHD medications and risk of serious cardiovascular events in young and middle-aged adults. JAMA. 2011;306(24):2673–2683.</ref> These analyses attenuated the post-2006 cardiac-safety concerns that had driven the peripheral vasculopathy and sudden-cardiac-death warnings, though the FDA warnings remain in place.

| pharmacokinetics = '''Absorption:''' Rapid oral absorption; peak plasma levels in 1–2 hours for IR. Bioavailability is only ~30% due to extensive first-pass metabolism. Food modestly delays but does not significantly reduce absorption. The transdermal patch (Daytrana) bypasses first-pass and produces somewhat higher and steadier serum levels per dose. '''Distribution:''' Volume of distribution ~13 L/kg; plasma protein binding ~15%. Crosses the blood–brain barrier. '''Metabolism:''' Primarily metabolized by '''carboxylesterase 1 (CES1)''' in the liver, not by cytochrome P450 enzymes, to ritalinic acid, which is pharmacologically inactive. This metabolic route makes methylphenidate relatively free of CYP-mediated med interactions, distinguishing it from amphetamines. '''Stereochemistry:''' Methylphenidate has two stereocenters; the d-threo enantiomer carries essentially all pharmacologic activity. Dexmethylphenidate ([[Focalin]]) is the isolated d-threo enantiomer and is roughly twice as potent per milligram. '''Elimination:''' ~90% renally excreted as ritalinic acid; ~1% unchanged. Half-life of the parent compound is 2–3 hours, hence the need for extended-release formulations or multi-dose-daily schedules for sustained effect.<ref name="ritalin-label">U.S. Food and Drug Administration. Ritalin (methylphenidate hydrochloride) prescribing information. NDA 010187, Novartis Pharmaceuticals.</ref>

| pharmacodynamics = Methylphenidate binds to and competitively inhibits the dopamine transporter (DAT) and norepinephrine transporter (NET), blocking reuptake of these monoamines from the synaptic cleft. Unlike amphetamines, methylphenidate is '''not a substrate''' for the transporters, it doesn't enter the presynaptic terminal, doesn't displace dopamine from vesicles, and doesn't induce reverse transport. The result is increased extracellular dopamine and norepinephrine without the additional vesicular release amphetamines produce.

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* Narcolepsy

* Off-label: treatment-resistant depression (augmentation, especially in geriatric or medically ill patients), fatigue in advanced illness (cancer, HIV, multiple sclerosis), excessive daytime sleepiness in shift-work disorder

| dosing = '''Ritalin IR (children ≥6 y~~, adults~~):''' Start 5 mg PO twice daily (before breakfast and lunch); titrate by 5–10 mg/week. Max 60 mg/day in 2–3 divided doses.

| dosing = '''Ritalin IR (FDA-approved for children ≥6 y; adult use is common clinical practice but off-label for IR Ritalin specifically; several ER formulations carry adult ADHD indications):''' Start 5 mg PO twice daily (before breakfast and lunch); titrate by 5–10 mg/week. Max 60 mg/day in 2–3 divided doses.

'''Ritalin LA / Metadate CD:''' 20 mg PO once daily AM; titrate by 10–20 mg weekly. Max 60 mg/day.

'''Concerta (osmotic ER):''' Start 18 mg PO once daily AM. Titrate by 18 mg/week. Max 72 mg/day (adults); 54 mg/day (children).

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| effects = ''Therapeutic:'' improved attention, reduced impulsivity and hyperactivity, increased wakefulness, mild mood elevation, mild appetite suppression. Generally described as "smoother" and less euphoric than amphetamines at equivalent doses.

''Common adverse:'' decreased appetite, insomnia (especially with late dosing), headache, abdominal pain, mild irritability, dry mouth, mild elevation of heart rate and blood pressure, weight loss.

| adverse = * '''Cardiovascular:''' tachycardia, mild–moderate hypertension; rare reports of sudden cardiac death in patients with structural heart disease (~~FDA warning~~)

| adverse = * '''Cardiovascular:''' tachycardia, mild–moderate hypertension; rare reports of sudden cardiac death in patients with structural heart disease.<ref name="fda-mph-cv-2007">U.S. Food and Drug Administration. FDA Directs ADHD Drug Manufacturers to Notify Patients about Cardiovascular Adverse Events and Psychiatric Adverse Events. February 21, 2007.</ref><ref name="vetter2008">Vetter VL, Elia J, Erickson C, et al. Cardiovascular monitoring of children and adolescents with heart disease receiving medications for attention deficit/hyperactivity disorder: a scientific statement from the American Heart Association. Circulation. 2008;117(18):2407–2423.</ref>

* '''Psychiatric:''' anxiety, agitation, irritability, mood lability; rarely psychosis or mania (especially in patients with bipolar predisposition)

* '''Tics''', methylphenidate can unmask or worsen motor/vocal tics; comorbid Tourette syndrome is a traditional but increasingly contested relative contraindication

* '''Dependence and misuse''', Schedule II; oral therapeutic use has lower abuse liability than amphetamines, but crushed/insufflated/IV misuse is significant

* '''Growth suppression''', modest reduction in height/weight velocity in chronically-treated children

* '''Priapism''', rare but documented; FDA warning, especially in adolescents

* '''Priapism''', rare but documented; FDA warning, especially in adolescents.<ref name="fda-mph-priapism-2013">U.S. Food and Drug Administration. FDA Drug Safety Communication: Safety review update of medical drugs used to treat Attention-Deficit/Hyperactivity Disorder (ADHD) in adults. December 17, 2013 (priapism class warning).</ref>

* '''Peripheral vasculopathy''', Raynaud-like phenomenon, rare digital ischemia

* '''Peripheral vasculopathy''', Raynaud-like phenomenon, rare digital ischemia.<ref name="fda-mph-vasculopathy-2006">U.S. Food and Drug Administration. FDA Drug Safety Communication: peripheral vasculopathy including Raynaud phenomenon associated with stimulants used to treat ADHD. December 2006.</ref>

* '''Lowered seizure threshold''', caution in epilepsy

* '''Lassitude / "crash"''' on withdrawal, fatigue, dysphoria, rebound hyperactivity

* '''Stereotyped behaviors''', rare at therapeutic doses

* '''Skin reactions''', chemical leukoderma (permanent depigmentation) at Daytrana patch application sites

* '''Skin reactions''', chemical leukoderma (permanent depigmentation) at Daytrana patch application sites.<ref name="fda-daytrana-leukoderma-2015">U.S. Food and Drug Administration. FDA Drug Safety Communication: Permanent skin color loss (chemical leukoderma) reported with use of Daytrana patch (methylphenidate transdermal system). June 24, 2015.</ref>

| interactions = * '''MAOIs''' (phenelzine, tranylcypromine, selegiline, linezolid), hypertensive crisis risk; contraindicated

* '''Tricyclic antidepressants''', ~~methylphenidate may elevate~~ TCA ~~plasma~~ levels; ~~additive cardiovascular effects~~

* '''Tricyclic antidepressants''', additive sympathomimetic cardiovascular effects (tachycardia, hypertension). Older case reports suggested possible PK interaction elevating TCA levels; modern reviews do not support a clinically significant PK interaction as methylphenidate does not appreciably inhibit CYP2D6.

* '''Warfarin / coumarins''', methylphenidate may elevate INR

* '''Phenytoin, phenobarbital, primidone''', methylphenidate may elevate anticonvulsant levels

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| anecdotes =

Rumor has it that can be more ~~effect~~ during luteal phase of ~~menstruation~~. Anyone have experience?

Rumor has it that it can be more effective during the luteal phase of the menstrual cycle. Anyone have experience?

</anecdote>

| seealso = [[Mixed amphetamine salts]], [[Dextroamphetamine]], [[Dexmethylphenidate]], [[Lisdexamfetamine]], [[Modafinil]], [[Atomoxetine]], [[Viloxazine]]

| references =

| references = <references/>

}}

[[Category:Psychostimulants]]

[[Category:Methylphenidates (Phenidates)]]

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