Methylphenidate (or MPH) is an amphetamine-like central nervous system (CNS) stimulant commonly used in treating Attention Deficit Hyperactivity Disorder (ADHD) in children and adults. It is also one of the primary drugs used to treat symptoms chronic fatigue syndrome (CFS), symptoms of traumatic brain injury, and drowsiness brought on my narcolepsy. Common brand names of drugs containingmethylphenidate include Ritalin, Concerta and Methylin, among others. Ritalin is manufactured by Novartis AG. It was grantedFDA approval in 1980, ushering in the so-called generation of “Ritalin kids” as the drug became hugely popular in the 1980s for children diagnosed with ADD or ADHD.
Schedule II controlled substance
The mode of action in humans is not completely understood, but Ritalin is presumed to activate the brain stem arousal system and cortex to produce a stimulant effect. There is no specific evidence to clearly establish the mechanism Ritalin utilizes to produce its mental and behavioral effects in children, nor is there conclusive evidence regarding how these effects relate to the condition of the CNS.
Indications and Dosage:
Ritalin is indicated for the treatment of Attention Deficit Disorders and Narcolepsy. Attention Deficit Disorders (previously known as Minimal Brain Dysfunction in Children) can be maintained and treated with Ritalin, which will produce a stabilizing effect in children with some or all of the following developmentally inappropriate symptoms: short attention span, hyperactivity, moderate-to-severe distractibility, emotional lability, and impulsivity.
Commonly reported characteristics include all of the above as well as minor neurological signs and abnormal EEG. Learning may or may not be impaired as a result. The diagnosis must be based upon a complete history and evaluation of the child and not solely on the presence of one or more of these characteristics. Diagnosis of this syndrome should not be made with finality when the symptoms are only recent in origin
Treatment with Ritalin is not indicated for all children with this syndrome. Stimulants are not intended for use in children exhibiting symptoms secondary to environmental factors and/or primary psychiatric disorders, including psychosis. Appropriate educational placement is essential and psychosocial intervention is generally warranted.
Ritalin dosage should be individualized according to the patient’s needs and responses. For Ritalin tablets, divided doses 2 or 3 times per day should be administered, preferably 30 to 45 minutes before meals. The average dose is 20 to 30mg/day, but some patients may require 40 to 60mg/day. In other people, 10 to 15mg/day will prove efficient. Patients unable to sleep if medication is taken late in the day should take the last dose before 6pm.
Ritalin SR tablets have a duration of around 8 hours. Therefore, Ritalin SR tablets may be used instead of Ritalin tablets when the 8-hour dosage of SR corresponds to the titrated 8-hour Ritalin dosage. SR tablets must be swallowed whole and never chewed or crushed.
In children, Ritalin should be initiated in small amounts, with gradual weekly incremental increases. Daily dosage above 60mg is not recommended. If improvement is not seen after appropriately adjusting the dosage over the course of one month, the drug should be discontinued.
Begin with a 5mg dose twice daily (before breakfast and lunch) with gradual increases of 5 to 10mg/week. If aggravation of symptoms or other adverse effects occur, reduce the dosage or discontinue the drug if necessary. Ritalin should be periodically discontinued to assess the child’s condition. Improvement may be sustained when the drug is temporarily or permanently ceased. Drug therapy with Ritalin should not (and need not) be indefinite and may usually be discontinued after puberty.
Ritalin Side Effects and Interactions:
The most common adverse side effects reported are nervousness and insomnia, but those are usually controlled by reducing the dose and omitting the drug in the afternoon or evening. Other side effects include hypersensitivity (including skin rash, fever, arthralgia, exfoliative dermatitis and urticaria), anorexia, nausea, palpitations, headache, drowsiness, dizziness, dyskinesia, changes in pulse and blood pressure, tachycardia, angina, cardiac arrhythmia, weight loss and abdominal pain. There have also been rare reports of Tourette’s syndrome. Toxic psychosis has been reported.
Though no definite causal relationship has been established, there have been reports of abnormal liver function, isolated cases of cerebral arteritis and/or occlusion, leucopenia and/or anemia, scalp hair loss, and transient depressed mood. Very rare reports of neuroleptic malignant syndrome (NMS) have been observed, and in most of the cases, patients were concurrently receiving therapies associated with NMS. In a single report, a ten year old boy taking methylphenidate for approximately 18 months experienced an NMS-like even within 45 minutes of ingesting his first dose of venlafaxine. It is not certain if this was a drug-drug interaction, a response to either drug alone, or some other unknown cause.
In children, abdominal pain, loss of appetite, weight loss, tachycardia, and insomnia may occur more frequently.
Use of tricyclic antidepressants (such as desipramine) is contraindicated as Ritalin may dangerously increase their plasma concentrations, leading to potential toxic reactions, especially cardiovascular effects. As well, there are contraindications with the use of MAOIs such as Nardil or Parnate and certain other drugs.
Ritalin should not be administered to patients suffering from conditions including arrhythmia, hypertension or liver damage.
Information for Parents and Kids:
There has been concern expressed regarding over-prescription of Ritalin. Some consider treatment of children with stimulants to be controversial since the number of children taking these dugs has dramatically increased over the years. However, these criticisms may be unfounded due to statistics; the incidence of ADHD is believed to be between 3 and 5% of the population, while the number of American children taking Ritalin is estimated at one to 2 percent.
As well, there has been concern that prescription of stimulants may lead children into future addictions. However, recent research suggests that boys with ADHD treated with stimulants such as methylphenidate are actually less likely to abuse drugs and alcohol later in life. Researchers have also looked into the role of methylphenidate in affecting stature, with some studies noting slight decreases in height acceleration. Other studies show height may normalize by adolescence.
Though extremely rare, Ritalin has been found by coroners to be the cause of a few deaths among children.
The US Drug Enforcement Administration (DEA) and the United Nations International Narcotics Control Board have both expressed concern over the relative ease with which legally prescribed Ritalin has been diverted to the illicit market. According to the DEA, “The increased use of this substance for the treatment of ADHD has paralleled an increase in its abuse among adolescents and young adults who crush these tablets and snort the powder to get high. Youngsters have little difficulty obtaining methylphenidate from classmates or friends who have been prescribed it.”
Warnings and Precautions:
Sufficient data on the safety and efficacy of long-term use of Ritalin in children are not yet available. A causal relationship has not been established, but suppression of growth (i.e. weight gain, and/or height) has been reported with long-term use of stimulants in children. Thus, careful monitoring of those requiring long-term therapy is recommended.
Ritalin should not be used in children under six years of age, as there is no substantial data for the safety and efficacy in this age group. As well, Ritalin should not be used for severe depression of either exogenous or endogenous origin. Clinical information suggests administration of Ritalin to psychotic children may exacerbate symptoms of behavior disturbance and thought disorder.
Ritalin should not be administered to prevent or treat normal fatigue states.
There is some evidence of Ritalin lowering the convulsive threshold in patients with a history of seizures, EEG abnormalities in absence of seizures, and (very rarely) in absence of history of seizures and no prior EEG evidence of seizures. Safe concomitant use of anticonvulsants and Ritalin has not been established. The drug should be discontinued in the presence of seizures.
In hypertensive patients, Ritalin should be used with caution. Blood pressure should be monitored in all patients taking methylphenidate, but especially in those with hypertension. Symptoms of visual disturbances have been seen in rare instances. As well, reports have been made of difficulty with accommodation and blurred vision.
Methylphenidate should be used cautiously in emotionally unstable patients, such as persons with a history of drug dependence or alcoholism, because of the risk of such patients increasing their own dosage unnecessarily.
Chronic abuse of methylphenidate may lead to tolerance and psychic dependence with varying degrees of abnormal behavior. Frank psychotic episodes can occur, and careful supervision is required during drug withdrawal, since severe depression as well as the effects of chronic over-activity can be unmasked.
Individuals with an element of agitation may react adversely, and the drug should be discontinued if necessary. Before a physician prescribes Ritalin to a child, the chronicity and severity of the child’s symptoms and their age should be taken into careful consideration. Prescription should not depend solely on the presence of one or more of the behavioral characteristics. When these symptoms are associated with acute stress reactions, Ritalin is normally not indicated for treatment.
Adequate clinical studies of Ritalin’s effects in pregnant women have not been conducted. Ritalin should only be administered during pregnancy if the potential benefit justifies the potential fetal risk. It is currently unknown whether methylphenidate is excreted in human breast milk. Because many drugs are excreted in human milk, caution should be exercised in nursing women.
Addiction & Withdrawal:
There is risk of addiction with methylphenidate, as the patient can depend on the immediate, predictable high Ritalin provides.
Ritalin withdrawal varies in severity and length. The withdrawal symptoms associated with Ritalin include agitation, nausea, insomnia, severe depression, over-activity, irritability, suicidality, worsening of ADHD-like symptoms, anxiety, exhaustion, and abdominal cramps. The American Psychiatric Association (APA) lists the major “complication” of Ritalin withdrawal as suicide in their Diagnostic and Statistical Manual (DSM-IV).
Over-dosage & Contraindications:
Signs and symptoms of methylphenidate overdosage, resulting principally from over-stimulation of the CNS and excessive sympathomimetic effects, may include vomiting, tremors, hyperreflexia, muscle twitches, agitation, convulsions (may be followed by coma), euphoria, confusion, hallucinations, delirium, sweating, flushing, tachycardia, headache, hyperpyrexia, palpitations, cardiac arrhythmias, hypertension, mydriasis, and drying of mucous membranes.
In treating a methylphenidate overdose, it is necessary to protect the individual from self-injury and external stimuli that would aggravate the over-stimulation already present. Gastric contents may be evacuated by gastric lavage (stomach pumping). In the case of severe intoxication, use a carefully titrated dosage of a short-acting barbiturate before pumping the stomach. Other measures for detoxifying the stomach and bowels include administration of activated charcoal and a cathartic.
Intensive care must be provided to maintain adequate circulation and respiratory exchange. External cooling procedures may be required in the case of hyperpyrexia. The efficacy of peritoneal dialysis or extracorporeal hemodialysis for Ritalin overdosage has not been established.
Generic Name: methylphenidate
Chemical Formula: C14H19NO2
Routes of Administration: oral
Elimination Half Life: 2-4 hours
Legal Status: by prescription only