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Oral Medications for Attention Deficit/Hyperactivity Disorder (AD/HD)
 
Preface

Attention deficit/hyperactivity disorder (AD/HD) is a behavioural disorder characterized by inattention, hyperactivity and impulsivity. These symptoms cause difficulties in learning and interpersonal relationships, which may lead to emotional problems or low self-esteem, resulting in multiple functional problems. While AD/HD is often thought of as a childhood developmental disorder, some adults may have AD/HD but have never been diagnosed.

The exact cause of AD/HD is not clear. Research has suggested that genetic factors play an important role in AD/HD. Exposure to environmental toxins (e.g. lead) during pregnancy, prematurity, low birth weight, a history of encephalitis, metabolic abnormalities, epilepsy and brain injury are possible risk factors for AD/HD.

Treatment approaches vary between children and adults, and treatment strategies for children with AD/HD vary according to age. Treatment can help to control the symptoms of AD/HD and improve the child’s functioning in everyday life, at home and at school. Options of treatment for AD/HD include behavioural therapy and medications.


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Oral Medications for AD/HD

In general, there are currently two main types of AD/HD medications:

a) Stimulants: These medicines work by elevating the levels of certain neurotransmitters in the brain, such as dopamine and norepinephrine, to target the AD/HD symptoms of inattention, hyperactivity and impulsivity. Common examples of stimulants include methylphenidate (short-acting or long-acting), lisdexamfetamine.

b) Non-stimulants: Non-stimulants work differently from stimulants, and they take longer to start working compared to stimulants. A common example of non-stimulant is atomoxetine.

In Hong Kong, all registered medicines for AD/HD are classified as prescription-only medicines and must be administered strictly under a doctor’s instruction and close medical supervision. Do not self-medicate or administer AD/HD medication to your child without a doctor’s assessment and supervision.

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Common Side Effects of Oral Medications for AD/HD
Medications for AD/HD* Common side effects*
Stimulants
Methylphenidate
  • Loss of appetite
  • Gastrointestinal upset
  • Headache
  • Increased heart rate
  • Insomnia
  • Cough
  • Depression
  • Dizziness
  • Drowsiness
  • Dry mouth
  • Mood altered
Lisdexamfetamine
  • Upper abdominal pain
  • Anxiety
  • Appetite decreased
  • Abnormal behaviour
  • Constipation
  • Diarrhoea
  • Dizziness
  • Dry mouth
  • Headache
  • Increased heart rate
  • Insomnia
  • Mood altered
Non-stimulants
Atomoxetine
  • Anxiety
  • Appetite decreased
  • Constipation
  • Depression
  • Dizziness
  • Drowsiness
  • Gastrointestinal discomfort
  • Headache
  • Mood altered
  • Nausea and vomiting
  • Sleep disorders
  • Weight decreased
 

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General Advice on Taking Oral Medications for AD/HD*


  • As stimulants carry a risk of misuse and abuse, you should strictly follow your doctor’s instructions and take the medication exactly as prescribed. Do not change the dose or stop taking the medication suddenly without medical advice.
  • Swallow extended-release capsules whole and should not be chewed or crushed, unless otherwise instructed by your doctor or pharmacist.
  • Do not self-medicate or administer AD/HD medication to your child without a doctor’s assessment and supervision.
  • Do not share your AD/HD medication with others.
 General advice
 

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Communication with Your Doctor*



  • Inform your doctor about your current medications and medical history, as some medications may interact with AD/HD medications, and certain medical conditions may require special precautions.

  • Patients should be monitored for side-effects of AH/HD medications, such as changes in sleep pattern, signs of suicide-related behaviour, reduced appetite, weight loss, mood changes, or changes in blood pressure and heart rate. Medical advice should be sought promptly if any side effects suspected to be related to their AD/HD medication occur.

  General advice

  • Attend regular medical follow-up appointments as scheduled to monitor progress safely.


 

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Storage of Oral Medications for AD/HD

Oral medications for AD/HD should be stored in a cool, dry place. Do not refrigerate unless specifically directed on the label. Always keep medications out of reach and sight of children to prevent accidental ingestion.




* This information may not cover all possible side effects, precautions, or medical advice. Always consult your healthcare professional for guidance.
 

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Drug Office
Department of Health
October 2026

 

 

 

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