Generic Name

Methylphenidate

Brand Names

*Ritalin*) blocks the dopamine transporter (DAT) and, to a lesser extent, the norepinephrine transporter (NET).

Mechanism

• Methylphenidate (brand name *Ritalin*) blocks the dopamine transporter (DAT) and, to a lesser extent, the norepinephrine transporter (NET).
• By inhibiting reuptake, it increases extracellular levels of dopamine and norepinephrine in prefrontal cortex and other limbic structures.
• The resultant surge in catecholamines enhances attention, impulse control, and working‑memory circuits.

Pharmacokinetics

• Absorption: Rapid oral absorption; peak plasma concentrations within 30–60 min.
• Half‑life: 2–3 h for immediate‑release; 3–6 h for extended‑release formulations.
• Metabolism: Primarily hydrolysis to inactive metabolites; minimal CYP450 involvement → low drug–drug interaction potential.
• Excretion: Renal elimination; caution in renal impairment.

Indications

• Attention‑Deficit/Hyperactivity Disorder (ADHD) in children and adults.
• Narcolepsy (exogenous methylphenidate formulation).
• Off‑label use: fatigue in psychiatric disorders, mild cognitive impairment (limited evidence).

Contraindications

• Absolute contraindications: Untreated pheochromocytoma, severe cardiac disease (ischemic heart disease, arrhythmias).
• Relative contraindications: Prior stroke, uncontrolled hypertension, mania.
• Warnings:
• Potential for abuse/withdrawal → schedule II controlled substance.
• Can worsen anxiety, insomnia, tics, or exacerbate psychiatric symptoms.
• Growth suppression in children—monitor height/weight quarterly.

Dosing

• Adults: Start 10 mg PO BID (Morning + Mid‑afternoon); titrate every 3–5 days up to 60 mg/day (max 72 mg/day).
• Children (6–12 yrs): 5–10 mg PO BID, max 40 mg/day.
• Extended‑release (ER): 20 mg QD, titrate to 40–90 mg/day.
• Narcolepsy: 10–20 mg PO BID.
• Administer with food to reduce GI upset; avoid late‑day dosing to minimize insomnia.

Adverse Effects

• Common:
• Insomnia, decreased appetite, weight loss.
• Headache, stomach pain, dizziness.
• Serious:
• Cardiovascular: ↑BP, tachycardia, arrhythmias.
• Psychiatric: agitation, mania, psychosis.
• Rare: catatonia, severe hypertension, thrombosis.
• Reproductive: Short‑term use may increase recurrence of pre‑existing cardiac lesions.

Monitoring

• Baseline: BP, HR, ECG (if cardiac history), growth charts, baseline weight.
• Follow‑up:
• BP/HR q4–6 weeks in the first 3 months, then every 3 months.
• Weight, appetite, growth every 6 months in children.
• Psychiatric status monthly for the first 2 months, then quarterly.
• Lab: CMP and CBC not routinely required unless clinically indicated.

Clinical Pearls

• Titration Strategy: Use a "step‑ and‑wait" regimen—adjust dose only after 5 days at a stable level; this reduces overshoot and side‑effect risk.
• ER vs IR: For school/work schedules, ER allows once‑daily dosing, improving adherence, but IR provides better symptom control in the late afternoon when symptoms recur.
• Growth Suppression: Weight loss is dose‑related; consider rotating to non‑stimulant therapy (e.g., atomoxetine) after 1–2 years of stimulant therapy in children with growth concerns.
• Cardiac Screening: A baseline ECG is reasonable only in patients with risk factors; routine ECG every 6 months is not required in low‑risk adults.
• Ocular Refraction: Refractive errors can fluctuate; coordinate with optometry when prescribing in children undergoing rapid visual development.
• Medication‑Drug Interaction: Co‑administration with MAO inhibitors or serotonergic agents should be avoided due to serotonin syndrome risk.

*This drug card uses up‑to‑date evidence‑based pharmacology to support medical education and clinical decision‑making.*