Methylphenidate

Oral
Narcolepsy
Adult: 20-30 mg daily in divided doses. Effective dose: 10-60 mg daily.

Oral
Hyperactivity disorders
Child: 6-17 yr As immediate-release preparation: Initially, 5 mg once or bid. May increase to 5-10 mg at wkly intervals, if necessary. Max: 60 mg daily in divided doses. Consider a later dose in the evening if the effect wears off. Discontinue periodically to re-evaluate or if there is no improvement w/in 1 mth. Modified-release forms: Dose varies depending on brand.

Transdermal
Hyperactivity disorders
Child: 6-17 yr : As patch delivering 1.1-3.3 mg/hr: Apply to hip area once daily in the morning 2 hr before an effect is needed and remove after 9 hr. Start w/ the lowest patch strength, then titrate according to response. Increase at wkly intervals as needed. Max: 3.3 mg/hr (at wk 4).

Methylphenidate (concerta): May be taken with or without food. Swallow whole, do not divide/chew/crush.
Methylphenidate (ritalin): Should be taken on an empty stomach. Take 30-45 min before meals.

History of marked anxiety, tension, agitation; glaucoma; hyperthyroidism; anorexia; phaeochromocytoma; tics or family history or diagnosis of Tourette's syndrome. Pre-existing CV disorders (e.g. severe HTN, heart failure, angina, MI, arrhythmia); aneurysm; vascular abnormalities. Concomitant or w/in 14 days of MAOI use.

Patient w/ history of seizure disorder, alcohol or drug abuse. HTN and other CV disorders that might be exacerbated by increases in BP or heart rate; pre-existing psychosis or bipolar disorder. Childn. Pregnancy and lactation. Patient Counselling This drug may cause dizziness, drowsiness and visual disturbances, if affected, do not drive or operate machinery. Avoid exposure of application site to any direct external heat source (TTS). Monitoring Parameters Monitor pulse, BP, psychiatric symptoms, appetite, wt and height prior to initiation, every dose adjustment and at least 6 mthly. Periodic CBC w/ differential and platelet count during prolonged therapy. Monitor for blisterings or oedema which does not improve w/in 48 hr of patch removal, or spreads beyond patch site.

Abdominal pain, aggression, alopecia, anorexia, arrhythmias, arthralgia, asthenia, changes in BP, cough, depression, diarrhoea, dizziness, dry mouth, dyspepsia, fever, growth restriction, headache, insomnia, irritability, movement disorders, nasopharyngitis, nausea, nervousness, palpitation, pruritus, rash, wt loss, tachycardia, tics, vomiting, confusion, abnormal dreams, constipations, dyspnoea, epistaxis, muscle cramps, suicidal ideation, urinary frequency. Rarely, angina, sweating, visual disturbances, cerebral arteritis, blood disorders, angle-closure glaucoma, seizures, tolerance, MI. Transdermal: Insomnia, decreased appetite; nausea; tic, emotional instability; vomiting, anorexia; nasal congestion, nasopharyngitis; wt loss.

Symptoms: Vomiting, tremor, agitation, muscle twitching, hyperpyrexia, hallucinations, euphoria, confusions, delirium, sweating, flushing, headache, HTN, dryness of mucous membranes, tachycardia, mydriasis, palpitations. Management: Symptomatic and supportive treatment.

May reduce effects of antihypertensive agents. May increase serum levels of phenytoin, TCAs. Risk of sudden BP increase during surgery w/ halogenated anaesth. May enhance the adverse/toxic effects of clonidine.
Potentially Fatal: Increased risk of hypertensive crisis w/ MAOIs.

Food may increase oral absorption of immediate-release preparations. Alcohol may exacerbate adverse CNS effects.

False-positive result for amphetamine urine detection test.

Methylphenidate is a mild CNS stimulant which blocks the reuptake of norepinephrine and dopamine into presynaptic neurons. It also stimulates the cerebral cortex and subcortical structures causing increased sympathomimetic activity.
Onset: 20-60 min (immediate- or extended-release); 60-180 min (sustained-release); 60 min (TTS).
Duration: 3-5 hr (immediate-release); 6-12 hr (extended-release); 2-6 hr (sustained-release); 11-12 hr (TTS).
Absorption: Readily absorbed from the GI tract (oral). Food enhances rate of absorption. Time to peak plasma concentration: Approx 2 hr (immediate-release).
Distribution: Distributed into breast milk. Plasma protein binding: 10-33%.
Metabolism: Undergoes extensive first-pass metabolism. Extensively metabolised via de-esterification by carboxylesterase CES1A1 to ritanilic acid.
Excretion: Via urine (90% as metabolites and unchanged drug) and faeces (small amounts). Plasma elimination half-life: Approx 2 hr (oral); approx. 3-4 hr (TTS).

Oral: Store between 20-25°C. Protect from light and moisture. Transdermal: Store between 20-25°C. Protect from light and moisture.

Other CNS Drugs & Agents for ADHD

N06BA04 - methylphenidate ; Belongs to the class of centrally-acting sympathomimetics. Used as CNS stimulant.