METHYLIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for METHYLIN (METHYLIN).
Methylphenidate is a central nervous system stimulant. It blocks the reuptake of dopamine and norepinephrine into presynaptic neurons, increasing their concentrations in the synaptic cleft.
| Metabolism | Hepatic via carboxylesterase CES1A1 to ritalinic acid (major inactive metabolite). Minor pathways: hydroxylation and glucuronidation. |
| Excretion | Renal: 90% (mainly as metabolites, 30-50% as unchanged drug); fecal: <1% |
| Half-life | 2-4 hours (short elimination half-life, requiring multiple daily dosing; immediate-release: 3-4 hours, extended-release: 3-6 hours) |
| Protein binding | 10-33% (bound to albumin; low binding reduces drug interactions) |
| Volume of Distribution | 3.1-4.4 L/kg (large Vd indicating extensive tissue distribution; higher in children than adults) |
| Bioavailability | Oral immediate-release: 30-60% (±11%); extended-release: 58-72% (with food decreases rate but not extent); transdermal: 40-60% (delayed onset) |
| Onset of Action | Oral immediate-release: 30-60 minutes; oral extended-release: 1-2 hours; transdermal: 2-3 hours; intravenous: 1-5 minutes |
| Duration of Action | Oral immediate-release: 3-5 hours; oral extended-release: 8-12 hours; transdermal: 12 hours; intravenous: 1-2 hours |
10 mg orally twice daily, administered 4-6 hours apart; doses may be adjusted in 5-10 mg increments weekly up to 60 mg/day.
| Dosage form | TABLET, CHEWABLE |
| Renal impairment | No specific adjustment required; methylphenidate is minimally renally excreted. Use with caution in severe renal impairment (eGFR <30 mL/min). |
| Liver impairment | No specific adjustment recommended; use with caution in severe hepatic impairment (Child-Pugh class C). |
| Pediatric use | Initial 5 mg orally twice daily (ages 6-17); increase by 5 mg weekly; maximum 60 mg/day. |
| Geriatric use | Start at 5 mg orally once daily; titrate slowly due to increased sensitivity to adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for METHYLIN (METHYLIN).
| Breastfeeding | Methylphenidate is excreted into human milk. The milk-to-plasma ratio (M/P) is approximately 0.6. Breastfed infants may experience adverse effects such as insomnia, irritability, and weight loss. Caution is advised; consider discontinuing breastfeeding or the drug, taking into account the importance of the drug to the mother. |
| Teratogenic Risk | Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. In animal studies, methylphenidate has been shown to cause developmental toxicity at doses higher than clinical doses. Use during pregnancy only if potential benefit justifies potential risk to the fetus. First trimester: potential risk of congenital malformations; second and third trimesters: risk of decreased fetal growth and neonatal neurobehavioral effects. |
■ FDA Black Box Warning
METHYLIN has a high potential for abuse and dependence. Prolonged use may lead to drug dependence. Misuse may cause sudden death or serious cardiovascular adverse events.
| Serious Effects |
["Hypersensitivity to methylphenidate or any component","Concomitant use with monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing MAOIs","Glaucoma","History of drug abuse or dependence","Agitated states","Tics or Tourette's syndrome (relative","Severe hypertension or symptomatic cardiovascular disease"]
| Precautions | ["Serious cardiovascular events including sudden death in patients with pre-existing structural cardiac abnormalities","Blood pressure and heart rate increases; monitor regularly","Psychiatric adverse events (e.g., exacerbation of pre-existing psychosis, mania, aggression)","Long-term suppression of growth in children","Seizures: may lower seizure threshold","Peripheral vasculopathy including Raynaud's phenomenon"] |
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| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and weight. Assess for symptoms of stimulant abuse or dependence. Fetal monitoring includes ultrasound to monitor fetal growth and development. Neonatal monitoring for signs of withdrawal or adverse effects such as irritability, feeding difficulties, and growth parameters. |
| Fertility Effects | In animal studies, methylphenidate did not impair fertility at clinically relevant doses. Human data are insufficient to determine effects on fertility. May cause menstrual irregularities or decreased libido in some individuals. |