Methylphenidate hydrochloride, also known by the trade names Ritalin and Concerta, is a drug that has a stimulant action of central nervous system and is commonly used in the drug treatment of Attention Deficit Hyperactivity Disorder (ADHD).
This text is not intended to reproduce the package insert of methylphenidate supplied by the manufacturers. What we will do here is a critical review of the drug in a language more accessible to the lay public, eliminating the parts of the package that contain more technical language and highlighting the information that is really relevant to the patients who need to take the drug, such as posology, contraindications and effects adverse effects.
In this article we will cover the following points about methylphenidate (Ritalin):
- Mechanism of action.
- How to take.
- Side effects.
- Drug interactions.
If you are looking for information on attention deficit hyperactivity disorder, visit the following link: WHAT IS ADHD - Attention Deficit Disorder.
Mechanism of action of methylphenidate hydrochloride
Dopamine and noradrenaline are neurotransmitters that play a central role in stimulating the central nervous system, playing an important role in thinking and concentration.
Methylphenidate is a drug that acts by inhibiting the reuptake of dopamine and noradrenaline in the synaptic cleft, causing these two neurotransmitters to remain active longer. When more stimulating neurotransmitters are available to neurons, the result is an increase in alertness, concentration, and ability to control behavior.
Methylphenidate stimulates the central nervous system in a manner similar to amphetamines; however, their actions are milder. Another difference in relation to amphetamines is that methylphenidate produces more noticeable effects on mental activities than on motor activities.
What is Ritalin for?
Methylphenidate has basically only two indications:
- Pharmacological treatment of attention deficit hyperactivity disorder.
Apart from these two conditions mentioned above, there is no further formal indication for the use of Ritalin.
Ritalin to study
Due to its proven efficacy in increasing alertness and concentration, Ritalin media and among university students of "study drug" or intelligence".
Some scientific studies show that methylphenidate does indeed improve capacity in some areas of the intelligence, such as temporary memory - also called working memory - and the processing speed of information. The effects on concentration and problem-solving are less than expected, and in cases of long-term memory and visual learning, which involves the study of graphs, tables, maps and diagrams, the effect of Ritalin is practically none.
In practice, clinical trials have failed to prove that Ritalin is able to effectively improve the academic performance of healthy students who do not suffer from ADHD. Despite the greater ability to spend the night studying, in the long term, the use of this drug is not usually better grades and can still lead to serious dependence and side effects, as front.
How to take methylphenidate
Methylphenidate hydrochloride is marketed in the following forms:
- Concerta®: 18 mg, 27 mg, 36 mg and 54 mg tablets.
- Ritalin: 10 mg tablets.
- Ritalin LA®: Tablets of 10 mg, 20 mg, 30 mg and 40 mg.
The initial dose of Ritalin in children is usually 5 mg to 10 mg, and in adults 10 mg to 20 mg. The dose may be increased over the weeks as the clinical response.
The daily dose of Concerta can range from 18 to 72 mg.
The medicine should be taken once or twice a day and it is advised not to administer the second dose after 6 pm to decrease the risk of insomnia.
In children, the maximum daily dose is 60 mg, while in adults it is 80 mg.
Side effects of methylphenidate
Like any medicine, methylphenidate has its own list of possible adverse effects. Some are common, others are rare; some are mild, others are potentially serious. The following will list the most important side effects, using as a criterion their frequency and severity.
Common side effects of Ritalin
- Loss of appetite (up to 26% of patients).
- Headache (22%).
- Dry mouth (14%).
- Irritability (11%).
- Insomnia (13%).
- Nausea and vomiting (13%).
- Irritability (11%).
- Sore throat (10%).
- Coriza (10%).
- Emotional ability (9%).
- Weight loss (9%).
- Anxiety (8%).
- Abdominal pain (7%).
- Dizziness (7%).
- Palpitations (5%).
- Transpiration (5%).
- Depression (4%).
- Tremors (3%).
- Loss of libido (2%).
- Urticaria (2%).
- Cough (2%).
Adverse Reactions of Ritalin that require medical evaluation
If you experience any of the following symptoms, contact your doctor as this may be a sign of a more serious reaction to the medicine:
- Signs of anaphylaxis (swelling of the lips, mouth, or tongue or difficulty breathing).
- Rash (red spots all over the body).
- Blisters on the skin.
- High fever.
- Hypertensive peak.
- Seizure crisis.
- Paralysis of one of the limbs.
- Difficulty talking.
- Tachycardia (very fast heart beat).
- Ecchymosis (purple spots on the skin)
- Muscle spasms.
- Priapism (involuntary, prolonged and painful erection).
Except for tachycardia, which occurs in up to 5% of patients, all other reactions above are uncommon, often less than 1%.
The following conditions contraindicate the use of Ritalin:
- Uncontrolled hypertension.
- Cardiac insufficiency.
- History of cardiac arrhythmia.
- Coronary disease.
- Tourette's syndrome.
- Anxiety disorder.
Methylphenidate may cause dizziness, drowsiness, blurred vision, hallucinations or affect ability to concentrate. If you experience any of these symptoms while taking the medicine, you should not drive vehicles or operate machinery.
Methylphenidate is not contraindicated, but should be avoided during pregnancy and during breastfeeding, as animal studies have shown undesirable effects on the fetus. Therefore, Ritalin should only be given during pregnancy if your doctor thinks the benefits warrant the potential risk to the fetus.
Ritalin may cause loss of skin pigmentation. Therefore, its use should be done with care in patients who have vitiligo.
The association of methylphenidate with alcoholic beverages should be avoided as there is a greater risk of toxicity with serious side effects.
In case of surgery, the anesthetist should be advised regarding the use of Ritalin, since this drug may interact with some types of anesthetics.
Ritalin may give false positive results in tests for drug use at sporting events, thus being considered dopping.
The combination of methylphenidate with the following drugs is contraindicated:
- Monoamine oxidase inhibitors (MAOIs).
- Inhaled anesthetics.
The combination of methylphenidate with the following drugs should only be done with medical follow-up:
- Antihypertensives: reduction of drug efficacy and risk of hypertensive peak.
- Warfarin: increased blood concentration and increased risk of bleeding.
- Antidepressants: increased risk of drug toxicity.
- Phenytoin: increased risk of drug toxicity.
- Antihistamines: increases the blood concentration of methylphenidate.
- Clonidine: increased risk of drug toxicity.
- Cannabis: increases the risk of tachycardia.
- Bupropion increases the risk of epilepsy.
- Antipsychotics: increased risk of drug toxicity.
- Antiparkinsonians: increased risk of drug toxicity.
- Antacids: increases the blood concentration of methylphenidate.