Methylphenidate: 7 things you should know
Medically reviewed by C. Fookes, BPharm Last updated on Mar 14, 2019.
1. How it works
- Experts aren't exactly sure how methylphenidate works in attention deficit hyperactivity disorder (ADHD) but think it affects the reuptake of the neurotransmitters dopamine and norepinephrine, increasing their concentration in the neural synapse (the space between two nerves).
- Methylphenidate is composed of 2 enantiomers (optical isomers): d-threo and l-threo. The d-threo enantiomer is more pharmacologically active than the l-threo enantiomer and is available commercially as dexmethylphenidate.
- Methylphenidate belongs to the group of medicines known as central nervous system (CNS) stimulants.
- Methylphenidate may be used to treat attention deficit hyperactivity disorder (ADHD) in people aged 6 to 65.
- May also be given to treat attention deficit disorder (ADD) and narcolepsy.
- Methylphenidate should be used in addition to other treatment modalities such as psychotherapy, education, and social integration advice.
- Methylphenidate is available as immediate-release tablets and suspension and in an extended-release form.
- Generic methylphenidate is available.
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- A headache, abdominal pain, a loss of appetite, dry mouth, a fast heartbeat, nausea, nervousness, or insomnia. Rash, pruritus, irritability, an increase in blood pressure or excessive sweating may also occur.
- May precipitate the emergence of psychotic thoughts such as hallucinations, delusions or mania in children and adolescents without a prior history of such thoughts. Discontinuation of treatment may be appropriate if this happens.
- Methylphenidate can be addictive and cause dependence. The risk is greater with extended-release tablets and in people with a history of drug dependence and alcoholism. Tolerance can also develop to methylphenidate's effect.
- May impair judgment or reaction skills. Exercise caution before driving or operating machinery until the full effects of methylphenidate are known.
- Depression may occur in those discontinuing methylphenidate, particularly if they have been overusing it. Methylphenidate may also aggravate pre-existing symptoms of anxiety, agitation, tension, behavioral or thought disturbances and is best avoided in people displaying marked levels of these symptoms.
- May not be suitable for people with certain heart conditions, hyperthyroidism, and other psychiatric disorders including bipolar disorder. An increased risk of seizures, peripheral circulation problems, and visual disturbances have been associated with methylphenidate use. Should not be used in people with glaucoma, a history of tics or Tourette's syndrome, severe hypertension or cardiac disease.
- Alcohol may contribute to the side effects and interfere with the release of extended-release methylphenidate. Avoid.
- May interact with a number of other drugs including monoamine oxidase inhibitors (MAO inhibitors), and methylphenidate should not be used within 14 days of discontinuation of a MAO inhibitor, halogenated anesthetics (do not take methylphenidate on the day of surgery), warfarin, anticonvulsants, and some antidepressants.
- Reports indicate some temporary slowing of growth may occur when regular methylphenidate is given to children aged 7 through 10 years. Doctors should monitor the child's height and weight and consider stopping treatment if growth suppression is suspected.
- Has been associated with sudden death. Cases were mainly in children and adults with serious structural cardiac abnormalities or other serious heart problems. Avoid in those known to have these risk factors.
- Rare cases of priapism (painful erections more than 6 hours in duration) have been reported.
- Caution when using in people with pre-existing bowel problems (includes those with severe narrowing of the intestinal tract and gut motility disorders) as extended-release tablets maintain their shape and potentially may cause a blockage. May affect blood circulation in the hands and feet. Symptoms may improve after a dosage reduction or discontinuation.
- Periodic blood tests may be required with prolonged dosing.
- Drug testing will reveal a positive result for methylphenidate.
- Classified as a Schedule II controlled substance, meaning that methylphenidate has a high potential for abuse. Keep personal supplies of methylphenidate in a safe place, out of view of potential drug seekers.
Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.
- Some branded and generic versions of methylphenidate need to be taken 30 to 45 minutes before food. Ensure you know when to take your branded or generic version of methylphenidate.
- If taking multiple doses of methylphenidate, ensure that your last dose is taken before 6pm. Extended-release formulations of methylphenidate are usually taken as a single daily dose before breakfast. If you cannot swallow the extended-release capsule, it may be opened and the contents mixed with applesauce and swallowed whole.
- Take methylphenidate exactly as directed by your doctor. Do not increase the dosage unless your doctor has told you to do so.
- Swallow extended-release methylphenidate tablets or capsules whole with a glass of water. Do not chew, divide or crush or attempt to dissolve in water.
- Methylphenidate may impair your judgment or reaction skills and make driving or operating machinery difficult. Do not drive or operate machinery if methylphenidate affects you in this way.
- Avoid alcohol while you are taking methylphenidate. Alcohol may potentiate the side effects of methylphenidate and affect its absorption.
- Seek urgent medical attention if you develop any chest pain, shortness of breath or fainting while taking methylphenidate. Call your doctor if you have any new or worsening mental symptoms such as hallucinations, delusions, or hearing voices.
- Seek medical advice if any new numbness, pain, skin color change or sensitivity, or unexplained wounds occur in the fingers or toes. Seek emergency attention if painful, prolonged erections develop.
- Do not be concerned if you notice something in your stool that looks like a tablet. The casing of some extended-release forms of methylphenidate does not fully dissolve.
6. Response and Effectiveness
- It takes approximately 1.9 hours after taking a methylphenidate immediate-release tablet for it to reach its peak level in the blood.
- Extended-release tablets or capsules have a two-phase release system. Initial peak concentrations are reached within an hour following administration, and another peak is seen approximately three hours later.
- Some relief from the symptoms of ADHD may be noticed within one to two hours of dosing; however, it may take up to two weeks for the full effects of methylphenidate to develop.
Medicines that interact with methylphenidate may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with methylphenidate. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed. Common medications that may interact with methylphenidate include:
- Anticoagulants (blood thinners), such as warfarin, or other drugs that have blood thinning effects such as aspirin or NSAIDs
- Anticonvulsants, such as phenytoin, phenobarbital, or primidone
- Antidepressants, such as tricyclic antidepressants (eg, amitriptyline), monoamine oxidase inhibitors (eg, isocarboxazid, phenelzine, and tranylcypromine), or SSRIs (eg, fluoxetine, sertraline)
- Antipsychotics (such as butyrophenones, phenothiazines, or thioxanthenes) and atypical antipsychotics (eg, olanzapine, quetiapine, ziprasidone)
- Any medication that may cause drowsiness, such as benzodiazepines (eg, diazepam, lorazepam), first-generation antihistamines (such as doxylamine or promethazine), metoclopramide, or opioids (such as codeine, morphine)
- Cold, flu, or allergy medications that contain decongestants such as phenylephrine or pseudoephedrine
- Heart medications such as clonidine or methyldopa
- HIV medications (fosamprenavir, ritonavir)
- Other medications that affect serotonin, such as amphetamines, fentanyl, lithium, tramadol, triptans (eg, almotriptan, eletriptan, or sumatriptan), or St. John's Wort
Avoid drinking alcohol or taking illegal or recreational drugs while taking methylphenidate.
Note that this list is not all-inclusive and includes only common medications that may interact with methylphenidate. You should refer to the prescribing information for methylphenidate for a complete list of interactions.
Methylphenidate [Package Insert]. Revised 08/2018. Lannett Company, Inc. https://www.drugs.com/pro/methylphenidate-cd-capsules.html
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use methylphenidate only for the indication prescribed.
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