Guanfacine

What it is used for

• ADHD in children and young people aged 6 to 17, when stimulants are not suitable, not tolerated or not effective

Read our guides:

• ADHD

Off-label uses

Doctors sometimes prescribe a medicine for a condition it is not officially licensed for. This is called off-label use. It is legal and common when there is good evidence it helps, and your doctor should explain why they are suggesting it.

• ADHD in adults, under a specialist
• Tic disorders such as Tourette's syndrome

How it works

Guanfacine acts on alpha-2A receptors in the front part of the brain, which is involved in attention and controlling behaviour. This helps strengthen signals in this area and can reduce hyperactivity and impulsiveness.

Side effects

Like all medicines, Guanfacine can cause side effects, although not everyone gets them. Many are mild and ease after the first few weeks.

Common side effects

• feeling sleepy or tired
• headache
• stomach pain
• low blood pressure
• feeling dizzy
• weight gain

Tell your doctor or pharmacist if these bother you or do not go away.

Serious side effects

These are rare. Call 111 or contact your doctor straight away if you get:

• fainting or a very slow heartbeat
• extreme sleepiness

Call 999 if you have signs of a serious allergic reaction, such as swelling of your lips, mouth, throat or tongue, or trouble breathing.

You can report any side effect to the Yellow Card scheme, run by the medicines regulator.

Stopping and withdrawal

Important safety information

• Blood pressure, heart rate, height and weight are checked regularly.
• Avoid grapefruit juice and alcohol.
• Make sure your child drinks enough fluids, as dehydration can make dizziness worse.

Questions about your medicine?

A pharmacist can answer questions about your medicines for free, without an appointment. You can also ask your GP for a medication review. Check if you can get free prescriptions.