Cardiac adverse effects may include palpitations, changes in blood pressure and heart rate (typically mild), and tachycardia (rapid heart rate). Smokers with ADHD who take methylphenidate may increase their nicotine dependence, and smoke more often than before they began using methylphenidate, with increased nicotine cravings and an average increase of 1.3 cigarettes per day. Ophthalmologic adverse effects may include blurred vision caused by pupil dilatation and dry eyes, with less frequent reports of diplopia and mydriasis.There is some evidence of mild reductions in height with prolonged treatment in children. This has been estimated at 1 centimetre (0.4 in) or less per year during the first three years with a total decrease of 3 centimetres (1.2 in) over 10 years.Hypersensitivity (including skin rash, urticaria, and fever) is sometimes reported when using transdermal methylphenidate. The Daytrana patch has a much higher rate of skin reactions than oral methylphenidate.Methylphenidate can worsen psychosis in people who are psychotic, and in very rare cases it has been associated with the emergence of new psychotic symptoms. It should be used with extreme caution in people with bipolar disorder due to the potential induction of mania or hypomania. There have been very rare reports of suicidal ideation, but some authors claim that evidence does not support a link. Logorrhea is occasionally reported. Libido disorders, disorientation, and visual hallucinations are very rarely reported.
Priapism is a very rare adverse event that can be potentially serious.US Food and Drug Administration-commissioned studies in 2011, indicate that in children, young adults, and adults there is no association between serious adverse cardiovascular events (sudden death, heart attack, and stroke) and the medical use of methylphenidate or other ADHD stimulants.Because some adverse effects may only emerge during chronic use of methylphenidate, a constant watch for adverse effects is recommended.A 2018 Cochrane review found that methylphenidate might be associated with serious side effects such as heart problems, psychosis, and death. The certainty of the evidence was stated as very low.A 2018 review found tentative evidence that it may cause both serious and non-serious adverse effects in children. Overdose
The symptoms of a moderate acute overdose on methylphenidate primarily arise from central nervous system overstimulation; these symptoms include: vomiting, nausea, agitation, tremors, hyperreflexia, muscle twitching, euphoria, confusion, hallucinations, delirium, hyperthermia, sweating, flushing, headache, tachycardia, heart palpitations, cardiac arrhythmias, hypertension, mydriasis, and dryness of mucous membranes. A severe overdose may involve symptoms such as hyperpyrexia, sympathomimetic toxidrome, convulsions, paranoia, stereotypy (a repetitive movement disorder), rhabdomyolysis, coma, and circulatory collapse. A methylphenidate overdose is rarely fatal with appropriate care. Following injection of methylphenidate tablets into an artery, severe toxic reactions involving abscess formation and necrosis have been reported.Treatment of a methylphenidate overdose typically involves the administration of benzodiazepines, with antipsychotics, α-adrenoceptor agonists and propofol serving as second-line therapies. Addiction and dependence
Methylphenidate is a stimulant with an addiction liability and dependence liability similar to amphetamine.