Methylphenidate hydrochloride
Methylphenidate hydrochloride (Ritalin)
Methylphenidate hydrochloride
(meth-ill- FEN-ih-dayt)
Pregnancy Category: C Methylin PMS-Methylphenidate Riphenidate Ritalin Ritalin-SR (C-II) (Rx)

Classification: Central nervous system stimulant

Action/Kinetics: May act by blocking the reuptake mechanism of dopaminergic neurons. In children with attention-deficit disorders, methylphenidate causes decreases in motor restlessness with an increased attention span. In narcolepsy the drug acts on the cerebral cortex and subcortical structures (e.g., thalamus) to increase motor activity and mental alertness and decrease fatigue. Peak blood levels, children: 1.9 hr for tablets and 4.7 hr for extended-release tablets. Duration: 4-6 hr. t 1/2: 1-3 hr. Metabolized by the liver and excreted by the kidney.

Uses: Attention-deficit disorders in children as part of overall treatment regimen. Narcolepsy. Investigational: Depression in elderly, cancer, and poststroke clients. Anesthesia-related hiccups.

Contraindications: Marked anxiety, tension and agitation, glaucoma. Severe depression, to prevent normal fatigue, diagnosis of Tourette's syndrome, motor tics. In children who manifest symptoms of primary psychiatric disorders (psychoses) or acute stress.

Special Concerns: Use with caution during lactation. Use with great caution in clients with history of hypertension or convulsive disease. Safety and efficacy in children less than 6 years of age have not been established.

Side Effects: CNS: Nervousness, insomnia, headaches, dizziness, drowsiness, chorea, depressed mood (transient). Toxic psychoses, dyskinesia, Tourette's syndrome. Psychologic dependence. CV: Palpitations, tachycardia, angina, arrhythmias, hyper- or hypotension, cerebral arteritis or occlusion. GI: Nausea, anorexia, abdominal pain, weight loss (chronic use). Allergic: Skin rashes, fever, urticaria, arthralgia, exfoliative dermatitis, erythema multiforme with necrotizing vasculitis, erythema. Hematologic: Thrombocytopenic purpura, leukopenia, anemia. Miscellaneous: Hair loss, abnormal liver function.
In children, the following side effects are more common: anorexia, abdominal pain, weight loss (chronic use), tachycardia, insomnia.

Laboratory Test Alterations: Urinary excretion of epinephrine.

Overdose Management: Symptoms: Characterized by CV symptoms (hypertension, cardiac arrhythmias, tachycardia), mental disturbances, agitation, headaches, vomiting, hyperreflexia, hyperpyrexia, convulsions, and coma. Treatment: Symptomatic. Treat excess CNS stimulation by keeping the client in quiet, dim surroundings to reduce external stimuli. Protect the client from self-injury. A short-acting barbiturate may be used. Undertake emesis or gastric lavage if the client is conscious. Adequate circulatory and respiratory function must be maintained. Hyperpyrexia may be treated by cooling the client (e.g., cool bath, hypothermia blanket).

Drug Interactions: Anticoagulants, oral / Anticoagulant effect R/T liver breakdown Anticonvulsants (phenobarbital, phenytoin, primidone) / Anticonvulsant effect R/T liver breakdown Carbamazepine / Methylphenidate levels Guanethidine / Guanethidine effect by displacement from its action site MAO inhibitors / Possibility of hypertensive crisis, hyperthermia, convulsions, coma Tricyclic antidepressants / TCA effect R/T liver breakdown

How Supplied: Tablet: 5 mg, 10 mg, 20 mg; Tablet, Extended Release: 20 mg

Dosage
?Tablets Narcolepsy.
Adults: 5-20 mg b.i.d.-t.i.d. preferably 30-45 min before meals.
Attention-deficit disorders.
Pediatric, 6 years and older, initial: 5 mg b.i.d. before breakfast and lunch; then, increase by 5-10 mg/week to a maximum of 60 mg/day.
?Extended-Release Tablets Narcolepsy.
Adults: 20 mg 1-3 times/day q 8 hr, preferably on an empty stomach.
Attention-deficit disorders.
Pediatric, 6 years and older: 20 mg 1-3 times/day.