Drug Detail:Methylphenidate (Methylphenidate (oral) [ meth-il-fen-i-date ])
Drug Class: CNS stimulants
1. How it works
- Methylphenidate is a stimulant that may be used for the treatment of ADHD and narcolepsy.
- 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).
- Effects include CNS stimulation, such as increased alertness, increased motor activity, less fatigue, brighter spirits, mild euphoria; respiratory stimulation; and reduced appetite.
- 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.
2. Upsides
- Methylphenidate may be used to treat attention deficit hyperactivity disorder (ADHD) and attention deficit disorder (ADD) in adults and children aged 6 years and older.
- May also be used to relieve symptoms of 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.
- No clinically important changes in the QT interval have been reported following the administration of 40mg dexmethylphenidate.
- Dosages within the recommended range only modestly affect the circulatory system.
- Available in several different dosage forms, such as conventional tablets, oral solutions, extended-release capsules and suspension, and a transdermal system.
- Stored at room temperature (20-25C).
- Generic methylphenidate is available.
3. Downsides
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.
- The dosage of methylphenidate needs to be adjusted depending on individual requirements and responses. Discontinue treatment if a beneficial effect is not obtained within 1 month of dosage adjustment.
- 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, and 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 several other drugs including monoamine oxidase inhibitors (MAO inhibitors), and methylphenidate should not be used within 14 days of discontinuation of an MAO inhibitor, halogenated anesthetics (do not take methylphenidate on the day of surgery), warfarin, anticonvulsants, and some antidepressants.
- Abrupt withdrawal may cause withdrawal symptoms including extreme fatigue and depression. Taper down slowly under supervision.
- 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 people known to have these risk factors.
- May cause a modest increase in blood pressure and heart rate. Monitor all patients.
- 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 (including 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.
- Pregnancy category C means methylphenidate is not recommended during pregnancy unless the benefits outweigh the risks. Long-term developmental effects on breastfed infants are unknown.
- 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.
Note: 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. View complete list of side effects
4. Tips
- 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 6 pm. 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.
- If you are using the methylphenidate transdermal patches, be aware that absorption from these patches may be increased if they are exposed to external heat sources such as hair dryers, electric blankets, or heating pads.
- 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.
- Tell your doctor if you are pregnant or intend to become pregnant while taking methylphenidate. Breastfeeding is not generally recommended due to the unknown effects of methylphenidate exposure on the infant.
5. 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.
6. Interactions
Medicines that interact with methylphenidate may either decrease its effect, affect how long it works, 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
- gastrointestinal drugs such as antacids or H2 receptor antagonists
- halogenated anesthetics
- heart medications such as clonidine or methyldopa or any medication that lowers blood pressure
- 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
- pimozide
- thioridazine
- urinary-acidifying or alkalinizing agents (may increase or decrease clearance).
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.