What is methylphenidate, and how does it work (mechanism of action)?
Methylphenidate is a medication that stimulates the
central nervous system (CNS or brain) in a manner that is similar to the
amphetamines; however, its actions are milder than those of the amphetamines. An
additional difference is that methylphenidate produces more noticeable effects
on mental activities than on motor activities. Methylphenidate and amphetamines
both have abuse potential. In treating children with
attention-deficit
hyperactivity disorder (ADHD), methylphenidate produces a calming effect. This
results in a reduction in hyperactivity and an improvement in attention span.
Methylphenidate also is used to treat excessive sleepiness. Methylphenidate was
approved by the FDA in 1955.
What brand names are available for methylphenidate?
Ritalin, Ritalin SR, Ritalin LA, Concerta, Methylin, Methylin ER, Daytrana, Quillivant XR
Metadate CD, Metadate ER
Is this drug available as a generic in generic form?
Yes.
Do I need a prescription for methylphenidate?
yes
What are the side effects of methylphenidate?
The most common side effects with methylphenidate are:
Insomnia can be limited by taking
the drug before noon. For children taking methylphenidate for ADHD, the most
common side effects are loss of appetite, abdominal pain, weight loss, and sleep
problems. The rate and severity of these side effects are less than that seen
with dextroamphetamine (Dexedrine).
Other important side effects of methylphenidate include:
- nausea,
- vomiting,
- dizziness,
- palpitations,
- headache,
- involuntary movements,
- chest pain,
- increased heart rate,
- increased blood pressure, and
- psychosis.
There have been rare
reports of Tourette’s syndrome, a syndrome in which there are uncontrollable
tics such as grimacing occurring with methylphenidate use. Because of the potential for side effects,
methylphenidate should be used with caution by patients who have relatives with Tourette’s syndrome or have the syndrome themselves or who have severe anxiety,
seizures, psychosis, emotional instability,
major depression, glaucoma, or motor
tics.
Sudden discontinuation of long-term methylphenidate therapy may unmask
depression. Gradual withdrawal, under supervision, is recommended.
Methylphenidate is habit forming and should be used cautiously in individuals
with a history of drug or alcohol abuse. Chronic abuse can lead to tolerance and
psychological dependence leading to abnormal behavior.
Priapism defined as painful and nonpainful penile erection lasting more than 4 hours, have been reported in pediatric and adult patients treated with stimulants. The erection usually resolves when the drug is stopped. Prompt medical attention is required in the event of suspected priapism.
What is the dosage for methylphenidate?
The dose of methylphenidate is adjusted based on patients’ responses.
It may be given once, twice, or three times daily depending on formulation.
The
recommended dose for Concerta is 18-72 mg once daily.
The recommended dose for
Ritalin LA is 10-60 mg once daily and for regular Ritalin the recommended dose
is 10-60 mg daily in 2 or 3 divided doses.
Which drugs or supplements interact with methylphenidate?
The stimulation effects of methylphenidate on the CNS can
be additive when used with other chemicals and medications that stimulate the
CNS, such as caffeine (found in coffee, tea, or cola drinks), and
pseudoephedrine or phenylpropanolamine (found in many cough-and-cold
preparations). The combination of methylphenidate and monoamine oxidase
inhibitors (MAOIs), for example, isocarboxazid (Marplan), phenelzine (Nardil),
tranylcypromine (Parnate), and procarbazine (Matulane), should not be taken with
methylphenidate since a hypertensive crisis (severely high blood pressure) may
occur. Moreover, methylphenidate should not be given to any patient within 14
days of receiving such an inhibitor. The blood pressure lowering effects of
medications used to treat hypertension may be reduced by methylphenidate. As a
result, blood pressure needs to be monitored when starting or stopping
methylphenidate in patients who are receiving medications for controlling their
blood pressure.
PREGNANCY There are no adequate studies of methylphenidate in
pregnant
women.
Is methylphenidate safe to take if I’m pregnant or breastfeeding?
It is not known if methylphenidate is secreted in
breast
milk.
What else should I know about this drug?
What preparations of methylphenidate are available?
- Tablets: 5, 10, and 20 mg (Ritalin);
- Sustained-release tablets (Ritalin SR): 20 mg;
- Long acting tablets (Ritalin LA): 20, 30, and 40 mg.
- Extended release tablets (Concerta): 18, 27, 36, and 54 mg.
- Chewable tablets (Methylin): 2.5, 5, and 10 mg;
- Solution (Methylin): 5 mg/5 ml, 10 mg/5 ml.
- Extended release tablets (Methylin ER, Metadate ER): 10, 20 mg.
- Extended release capsules (Metadate): 10, 20, 30, 40, 50, and 60 mg.
How should I keep methylphenidate stored?
Tablets should be kept at room temperature, 15 C – 30 C (59 F – 86 F).