What is methylphenidate?
Methylphenidate (MPH) is an amphetamine-like prescription central nervous system (CNS) stimulant normally used to treat attention deficit hyperactivity disorder (ADHD) in children and adults. It is also one of the primary drugs used to treat symptoms of the traumatic brain injury and the daytime drowsiness symptoms of narcolepsy and chronic fatigue syndrome (CFS).
Patented in 1954 by the Ciba pharmaceutical company and initially used to treat depression, CFS and narcolepsy, it was used in the 1960s to treat children with ADHD, which was known at the time as hyperactivity or minimal brain dysfunction (MBD). Today methylphenidate is the most commonly prescribed medication in the world to treat ADHD.
It is estimated that over 75% of methylphenidate prescriptions are written for children, with boys being about four times as likely to receive the drug as girls. Production and prescription of methylphenidate saw significant gains in the 1990s, especially in the US, as the ADHD diagnosis came to light and became better understood and accepted in the medical and mental health communities.
Methylphenidate Treatment and usage:
Methylphenidate is indicated as an integral part of a total treatment plan typically including other remedial measures (educational, social, psychological) for a stabilizing effect in children with a behavioral syndrome.
Methylphenidate drugs such as Ritalin and Concerta are the most commonly prescribed medications for ADHD around the world. In children, it is claimed to have a “calming” effect on ADHD symptoms, reducing their impulsive behavior and tendency to “act out,” also helping the focus and concentrate on school and other tasks. Adults with ADHD often find the MPH increases their ability to focus on tasks and organize their lives.
Methylphenidate Method of action:
Methylphenidate’s method of action in humans is not well understood, but it presumably activates that brain stem arousal system and cortex to produce its stimulant effect. There is no specific evidence which clearly establishes the mechanism whereby Ritalin produces its mental and behavioral effects in children, nor is there conclusive evidence as to how these effects relate to the condition of the CNS.
Some researchers believe that ADHD is caused by a dopamine imbalance in the brains of those affected. MPH is a dopamine reuptake inhibitor, meaning it increases the levels of dopamine neurotransmitter in the brain by partially blocking the transporters that remove it from the synapses.
Warnings or dangers associated with methylphenidate:
In the US, methylphenidate is a Schedule II controlled substance with a high potential for abuse due to its addictive potential. In other countries around the world, it is a Schedule II drug under the Convention on Psychotropic Substances. Some individuals abuse MPH by crushing the tablets and snorting them, the “high” resulting from increased dopamine transporter blockage due to faster absorption into the bloodstream. In this respect, methylphenidate’s effect is similar to that of cocaine or amphetamine and such abuse can lead to addiction. When taken orally in prescribed doses, MPH has a low addiction liability and rarely produces a “high.”
Ritalin should not be used for severe depression of either exogenous or endogenous origin. Clinical experience suggests that in psychotic children, administration of methylphenidate may exacerbate symptoms of behavior disturbance and thought disorder. Additionally, methylphenidate should not be used to prevent or treat normal fatigue.
There is some evidence that Ritalin may lower the convulsive threshold in patients with prior history of seizures, with prior EEG abnormalities in absence of seizures, and, extremely 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. If seizures are present, methylphenidate use should be discontinued.
Methylphenidate should be administered with caution to patients with hypertension. Blood pressure should be monitored at appropriate intervals in all patients taking methylphenidate, especially those with hypertension. Symptoms of visual disturbances have been reported in some instances. As well, blurring of vision has been reported.
The drug should be given with caution to emotionally unstable patients, such as those with a history of drug dependence or alcoholism, because such patients may increase dosage on their own initiative.
Chronic abuse may lead to tolerance and psychic dependence with varying degrees of abnormal behavior. Frank psychotic episodes can occur. Patients with agitation may react adversely, and therapy should be discontinued if necessary.
Drug treatment is not indicated in all cases of behavioral syndrome and should only be considered after careful evaluation of the child’s history. The decision to prescribe Ritalin should depend on the physician’s assessment of the chronicity and severity of the child’s symptoms and their appropriateness for the child’s age. When symptoms are associated with acute stress reactions, treatment with methylphenidate is not normally indicated.
The most common side effects when taking methylphenidate include tachycardia, arterial hypertension, loss of appetite, abdominal pain, nausea/vomiting, blurred vision, pupil dilation (if snorted), muscle spasms/twitching, nervousness, euphoria, insomnia, drowsiness, dizziness, headache, dry mouth, irritability, tremors, hallucinations and rapid breathing.
Less common side effects that have been reported with methylphenidate include anorexia, palpitations, hypersensitivity, changes in blood pressure and pulse, cardiac arrhythmia, anemia, hair loss, toxic psychosis, abnormal liver function, leucopenia, cerebral arteritis and death. There have been at least 19 cases of sudden death in children taking methylphenidate, which have led the Drug Safety and Risk Management Advisory Committee to call on the FDA to require the most serious type of health warning on the labels of the drugs. This advice, however, was rejected by the FDA.
There is much criticism of methylphenidate due to its similarity to cocaine, accusations of overprescription, tendency for addiction, possible growth-stunting, risk of sudden death in children, illicit use, and the drug’s potential to be carcinogenic.
Methylphenidate Overdose and withdrawal:
Symptoms of acute methylphenidate overdose, resulting principally from overstimulation of the CNS and excessive sympathomimetic effects, may include vomiting, tremors, agitation, hyperreflexia, muscle twitches, convulsions (possibly followed by coma), euphoria, confusion, hallucinations, delirium, sweating, flushing, headache, hyperpyrexia, tachycardia, palpitations, cardiac arrhythmias, hypertension, mydriasis, and dryness of mucous membranes.
Consult with a Certified Poison Control Center regarding treatment for up-to-date guidance and advice. Treatment consists of appropriate supportive measures. The patient must be protected against self-injury and external stimuli that may aggravate the overstimulation already present. Gastric lavage may be performed. In the presence of severe intoxication, a carefully titrated dose of a short-acting barbiturate may be used prior to gastric lavage. Other measures of detoxification include administration of activated charcoal and a cathartic.
Patients taking methylphenidate may develop tolerance to the drug’s effects, and run the risk of withdrawal symptoms, sometimes severe, if the drug is discontinued abruptly. Symptoms of methylphenidate withdrawal include depression, paranoid feelings, thoughts of suicide, anxiety, agitation, and sleep disturbances.
Precautions with methylphenidate in children and the elderly:
Long-term effects of methylphenidate in children have not been well established. MPH should not be used in children under age six. There has been some mention that children who took methylphenidate for extended periods of time grew more slowly than expected. It is not known whether long-term use causes slowed growth, however. Children are generally more susceptible to methylphenidate and other stimulants, and as such, it is not uncommon for them to experience loss of appetite, sleep difficulty, stomach pain, rapid heartbeat and weight loss when taking methylphenidate.
Many medications have not been adequately studied in the elderly population. Therefore, it may be unknown whether they work exactly the same way as in younger adults or if different side effects and/or adverse events may occur. There is no specific information comparing the use of MPH in older adults with use in other age groups.
Types of methylphenidate:
Common forms of methylphenidate include Ritalin, Methylin, Concerta, Rubifen, Equasym, and Daytrana.