Methylphenidate is the most commonly used medicine for ADHD. It belongs to a group of medicines called stimulants, which work by increasing activity in the brain, particularly in areas that play a part in controlling attention and behaviour.

Methylphenidate may be offered to adults, teenagers and children over the age of 6 with ADHD.

Methylphenidate is only available on prescription. It comes as standard (immediate release) tablets and capsules and slow release (also called extended, modified or prolonged release) tablets and capsules.

Some children may need to take both slow release and standard methylphenidate to help improve their ADHD.

It's best to stick to the same brand, particularly if your child has slow release methylphenidate. Different brands work differently in how they release the medicine into the body, and this can affect how they work to manage your child's symptoms.

Common side effects of methylphenidate include:

• a small increase in blood pressure and heart rate

• loss of appetite, which can lead to weight loss or poor weight gain

• trouble sleeping

• headaches

• stomach aches

• feeling aggressive, irritable, depressed, anxious or tense

Lisdexamfetamine is a medicine that stimulates certain parts of the brain. It improves concentration, helps focus attention and reduces impulsive behaviour.

It may be offered to teenagers and children over the age of 5 with ADHD if at least 6 weeks of treatment with methylphenidate has not helped. 

Dexamfetamine is similar to lisdexamfetamine and works in the same way. It may be offered to adults, teenagers and children over the age of 5 with ADHD.

Dexamfetamine is usually taken as a tablet 2 to 4 times a day, although an oral solution is also available.

Common side effects of dexamfetamine include:

• decreased appetite

• mood swings

• agitation and aggression

• dizziness

• headaches

• diarrhoea

• nausea and vomiting

Atomoxetine works differently from other ADHD medicines.

It's a selective noradrenaline reuptake inhibitor (SNRI), which means it increases the amount of a chemical in the brain called noradrenaline.

This chemical passes messages between brain cells, and increasing it can aid concentration and help control impulses.

Atomoxetine may be offered to adults, teenagers and children over the age of 6 if it's not possible to use methylphenidate or lisdexamfetamine.

Atomoxetine has been linked to some more serious side effects that are important to look out for, including suicidal thoughts and liver damage.

Guanfacine acts on part of the brain to improve attention, and it also reduces blood pressure.

It may be offered to teenagers and children over the age of 6 if it's not possible to use methylphenidate or lisdexamfetamine.

Guanfacine is usually taken as a tablet once a day, in the morning or evening.

Common side effects include:

• tiredness or fatigue

• headache

• abdominal pain

• dry mouth