Ritalin (methylphenidate) is a stimulant drug frequently used as an ADHD medication in children. It works by increasing the levels of dopamine in the brain. Children with ADHD appear to display low activity in the parts of the brain controlling attention and behavior, and use of stimulants such as Ritalin can increase activity in these areas, thus alleviating the symptoms. There are a number of common Ritalin side effects in children; but due to the mild nature of most of these Ritalin continues to be used in the long-term treatment of ADHD.
Very Common Ritalin Side Effects
According to Netdoctor, very common side effects experienced when using Ritalin include nervousness, insomnia and headache. These relatively mild adverse effects are reported to be experienced by more than 1 in 10 children using Ritalin, but most consider them to be negligible when compared to the beneficial effects of the medication.
Cardiovascular Side Effects
Mild cardiovascular side effects are reported in more than 1 in 100 children using Ritalin. They include increases in blood pressure, increased heart rate and arrhythmias. These side effects are so mild that the American Heart Association does not consider cardiovascular monitoring to be necessary for children taking Ritalin. There has been one report of sudden death in a child taking Ritalin in combination with the anti-hypertensive drug clonidine, but the cause of this cannot be clearly linked to use of Ritalin.
Emotional Side Effects
Emotional side effects reported to be experienced by children taking Ritalin include depression, irritability, aggression and anxiety. However, some studies suggest Ritalin actually decreases irritability and anxiety in children suffering from ADHD compared with a placebo treatment. The assessment of emotional side effects for any psychosomatic drug can be problematic since it can be difficult to quantify the symptoms objectively. More serious emotional side effects such as psychotic disorders and suicidal thoughts have also been suggested to be caused by Ritalin, but are experienced by far fewer patients.
Gastrointestinal Side Effects
Ritalin is reported to cause a number of gastrointestinal side effects including abdominal pain, nausea and diarrhea, as well as loss of appetite. Gut disturbances are relatively common in children using Ritalin, and is experienced by more than 1 in 100 patients. A placebo-controlled study involving over 200 children found that appetite disturbance and stomach ache increased significantly when Ritalin was administered.
Other Side Effects
Other common Ritalin side effects in children include skin reactions, hair loss and joint pain. Ritalin has also been associated with some long-term effects such as growth deficits and addiction and rebound. But it has also been linked to a decreased risk of substance abuse in children suffering from ADHD. Rare side effects reported in around 1 in 1000 patients include twitching or tics, chest pain, blurred vision and fatigue.
 “Ritalin (methylphenidate)” Netdoctor
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 TE Wilens, SV Faraone, J Biederman “Does Stimulant Therapy of Attention-Deficit/Hyperactivity Disorder Beget Later Substance Abuse? A Meta-Analytic Review of the Literature” Pediatrics 111:179-185 (2003)