METHYLPHENIDATE HYDROCHLORIDE

METHYLPHENIDATE HYDROCHLORIDE (meth-ill-fen'i-date) Concerta, Daytrana, Metadate CD, Metadate ER, Methylin, Methylin ER, Ritalin, Ritalin LA, Ritalin SR Classifications: cerebral stimulant; Therapeutic:cerebral stimulant Prototype: Amphetamine Pregnancy Category: C Controlled Substance: Schedule II

Availability

5 mg, 10 mg, 20 mg tablets; 2.5 mg, 5 mg, 10 mg chewable tablets; 5 mg/5 mL, 10 mg/5 mL oral solution; 10 mg, 20 mg, 30 mg, 40 mg sustained release capsules; 10 mg, 18 mg, 20 mg, 27 mg, 36 mg, 54 mg sustained release tablet; 10 mg, 15 mg, 20 mg, 30 mg transdermal patch

Action

Piperidine derivative with actions and abuse potential qualitatively similar to those of amphetamine. Acts mainly on cerebral cortex exerting a stimulant effect. Results in mild CNS and respiratory stimulation with potency intermediate between amphetamine and caffeine.

Therapeutic Effect

Effects are more prominent on mental rather than on motor activities. Also believed to have an anorexiant effect.

Uses

Adjunctive therapy in hyperkinetic syndromes characterized by attention deficit disorder, narcolepsy, mild depression, and apathetic or withdrawn senile behavior.

Contraindications

Hypersensitivity to drug; history of marked anxiety, agitation; aortic stenosis; serious cardic disorders including arrhythmias; valvular heart disease; ventricular dysfunction; motor tics or Tourette's disease; substance abuse; severe anxiety, psychosis, major depression, suicidal ideation; glaucoma; pregnancy (category C), lactation, children <6 y of age.

Cautious Use

Alcoholic; emotionally unstable patient; abrupt discontinuation; recent MI, anxiety, cardiac arrhythmias, cardiac disease, dysphagia, older adults; esophageal stricture, GI obstruction, heart failure, hepatic disease, hyperthyroidism, history of paralytic ileus, cystic fibrosis, mania, radiographic contrast administration, seizure disorder, hypertension; history of seizures.

Route & Dosage

Narcolepsy Adult: PO 10 mg b.i.d. or t.i.d. 30–45 min p.c. (range: 20–40 mg/d) Attention Deficit Disorder Child: PO 5–10 mg before breakfast and lunch, with a gradual increase of 5–10 mg/wk as needed (max: 60 mg/d) or 20–40 mg sustained release q.d. before breakfast (max dose: 72 mg q.d.) Transdermal patch 10 mg patch worn for 9 hours x 1 wk then taper as needed. Increase no more than once weekly. Apply 2 hr before desired effect. Depression Geriatric: PO 2.5 mg in morning before 9 a.m., may increase by 2.5–5 mg q2–3d (max: 20 mg/d) divided 7 a.m. and noon

Administration

Oral

• Give 30–45 min before meals. To avoid insomnia, give last dose before 6 p.m.
• Ensure that sustained release form is not chewed or crushed. It must be swallowed whole.
• Can open Metadate CD capsules and sprinkle on food
• Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

CNS: Dizziness, drowsiness, nervousness, insomnia. CV: Palpitations, changes in BP and pulse rate, angina, cardiac arrhythmias, exacerbation of underlying CV conditions. Special Senses: Difficulty with accommodation, blurred vision. GI: Dry throat, anorexia, nausea; HEPATOTOXICITY; abdominal pain. Body as a Whole: Hypersensitivity reactions (rash, fever, arthralgia, urticaria, exfoliative dermatitis, erythema multiforme); long-term growth suppression.

Interactions

Drug: mao inhibitors may cause hypertensive crisis; antagonizes hypotensive effects of guanethidine, bretylium; potentiates action of cns stimulants (e.g. amphetamine, caffeine); may inhibit metabolism and increase serum levels of fosphenytoin, phenytoin, phenobarbital, and primidone, warfarin, tricyclic antidepressants.

Pharmacokinetics

Absorption: Readily from GI tract. Transdermal absorption increased with heat or inflamed skin. Peak: 1.9 h; 4–7 h sustained release, 2 h transdermal. Duration: 3–6 h; 8 h sustained release. Elimination: In urine.

Nursing Implications

Assessment & Drug Effects

• Monitor BP and pulse at appropriate intervals.
• Lab tests: Obtain periodic CBC with differential and platelet counts during prolonged therapy.
• Chronic abusive use can lead to tolerance, psychic dependence, and psychoses.
• Assess patient's condition with periodic drug-free periods during prolonged therapy.
• Supervise drug withdrawal carefully following prolonged use. Abrupt withdrawal may result in severe depression and psychotic behavior.

Patient & Family Education

• Report adverse effects to physician, particularly nervousness and insomnia. These effects may diminish with time or require reduction of dosage or omission of afternoon or evening dose.
• Check weight at least 2 or 3 times weekly and report weight loss. Check height and weight in children; failure to gain in either should be reported to physician.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug