Methylphenidate is a stimulant used to treat attention deficit hyperactivity disorder in children and adults. Most of its common side effects are predictable extensions of how it works, and many are dose-related or tied to when the dose wears off.
Common side effects and early adjustment effects
- Reduced appetite, often most noticeable at lunchtime. See appetite loss on ADHD medication.
- Difficulty falling asleep, particularly if a dose is taken late in the day. See ADHD medication and insomnia.
- Headache and stomach ache
- A faster heartbeat, and a modest rise in blood pressure
- Dry mouth
- Feeling irritable, tearful or flat as the dose wears off, often late afternoon
That last one, sometimes called rebound, is easy to mistake for the medicine making things worse. It is worth noting when in the day it happens, because a change in formulation or dose timing often addresses it.
Appetite suppression is usually manageable by shifting the pattern of eating rather than the amount: a substantial breakfast before the dose takes effect, and an evening meal once it has worn off.
Serious mood, behaviour or physical symptoms to take seriously
Heart symptoms. Get urgent help for chest pain, fainting, or a markedly fast or irregular heartbeat. Because stimulants raise heart rate and blood pressure, heart conditions and family history of sudden cardiac death are checked before starting, so make sure that history has been asked about.
New psychiatric symptoms. Report hallucinations, hearing or seeing things that are not there, suspiciousness, unusually elevated mood, or new or worsening thoughts of self-harm. These are uncommon but need prompt review rather than waiting for the next appointment.
Prolonged or painful erection. Rare, but it is a medical emergency and needs immediate care to avoid lasting damage. It is worth knowing in advance because embarrassment causes delay.
Also report: new or worsening tics or repetitive movements; severe anxiety or agitation; persistent stomach pain; unexplained weight loss; or circulation changes in the fingers and toes, such as numbness, coldness or colour change.
Sexual, sleep, weight and emotional side effects
Sleep is the effect most often needing adjustment. Taking the last dose earlier, or changing to a different release formulation, usually helps more than adding anything for sleep.
Weight and growth. Reduced appetite can lead to weight loss, and in children and adolescents growth is monitored for this reason. Report weight loss rather than waiting for a scheduled review.
Emotional effects. Some people describe feeling flattened, less spontaneous, or less themselves. This is a legitimate reason to review the dose, and it is often a sign the dose is higher than it needs to be rather than that the medicine is wrong.
Interactions, alcohol, pregnancy and other risk factors
- Decongestants in cold and flu remedies. Add to heart rate and blood pressure effects. See decongestants and blood pressure.
- Caffeine and stimulant supplements. Pre-workout products, fat burners and energy drinks compound jitteriness, palpitations and insomnia. See pre-workout side effects.
- Some antidepressants. Combinations are used deliberately at times but need supervision.
- Blood pressure medicines. Stimulants can work against them.
- Alcohol. Can mask how impaired you are and worsen mood effects.
- Pregnancy and breastfeeding. Needs individual discussion. See mental health medication in pregnancy.
What to ask your doctor before changing dose or stopping
Monitoring usually includes height and weight, particularly in children and adolescents, along with blood pressure and heart rate at review appointments. Growth is tracked because appetite suppression can affect it, and a treatment break is sometimes considered if growth slows.
Methylphenidate is a controlled medicine in South Africa. Keep it stored securely, do not share it, and account for what you have. Misuse and diversion are recognised problems, and a prescription that runs out faster than expected is worth raising rather than concealing.
- Could a different formulation reduce the afternoon rebound?
- When were height, weight, blood pressure and heart rate last checked?
- Should we consider a treatment break, and when?
- Which symptoms should I report immediately?
- What should I do about doses at weekends or during holidays?
Related mental health medication guides
- ADHD medication side effects
- ADHD medication in children and in adults
- Appetite loss, insomnia and heart rate on ADHD medication
- Mental health medication side effects
- Report a side effect in South Africa
See also Ritalin and Concerta, two methylphenidate brands, and atomoxetine, a non-stimulant alternative.
Medical Disclaimer: This content is for informational and educational purposes only and does not constitute medical diagnosis, prescription, or professional advice. Always read the patient information leaflet and consult a qualified doctor or pharmacist regarding any medicine or health concern.