Guanfacine
A once-a-day non-stimulant ADHD medicine for children and teenagers. Not addictive, used alone or with a stimulant, and plays the long game rather than the quick hit.
Quick answer: The most common side effects of guanfacine are sleepiness, headache, tummy pain and tiredness. It can also cause low blood pressure or a slow pulse, so these are checked regularly. It’s a non-stimulant ADHD medicine that builds up over 2–4 weeks. Don’t stop it suddenly, as blood pressure can rebound. Get help urgently for fainting or a very slow pulse.
At a glance
- For
- ADHD in children and teens aged 6–17 (sometimes adults, off-label)
- Works
- In a key trial, about 6 in 10 children responded, versus about 4 in 10 on a dummy treatment. A smaller effect than stimulants
- Cost
- $25 a script on the PBS for ADHD with an authority, if diagnosed at age 6–17 and started by a paediatrician or psychiatrist ($7.70 concession); private scripts cost more
- Kicks in
- Builds over 2–4 weeks as the dose is stepped up
- Taken for
- Months to years, reviewed at least yearly
- Watch for
- Sleepiness, tiredness, headache, tummy pain, low blood pressure or slow pulse
There’s no instant effect, so judge it after a month, not a morning.
Brand names
- Intuniv (extended-release tablets, taken once a day)
How it works
Guanfacine acts on alpha-2A receptors in the front of the brain, strengthening the signals that control attention, planning and impulses. It doesn’t work like a stimulant.
Used for
- ADHD in children and teenagers aged 6 to 17, when stimulants aren’t suitable, aren’t tolerated or aren’t enough (TGA-approved)
- Sometimes used in adults with ADHD by specialists (off-label)
Side effects
Full side-effect list (from the product information)
How often, from the official product information. Bold = serious.
Very common more than 1 in 10
- Sleepiness
- Headache
- Tummy pain
- Tiredness
Common 1 in 10 to 1 in 100
- Low mood, anxiety or mood swings
- Trouble sleeping or nightmares
- Sedation, lethargy or dizziness
- Slow heart rate
- Low blood pressure, incl. on standing
- Nausea, vomiting, diarrhoea or constipation
- Dry mouth
- Rash
- Bedwetting
- Irritability
- Less appetite, or weight gain
Uncommon 1 in 100 to 1 in 1,000
- Allergic reactions
- Agitation or seeing things that aren’t there
- Seizures
- Fainting
- Faster or irregular heartbeat, first-degree heart block
- Pale skin
- Asthma
- Indigestion
- Itch
- Passing urine more often
- Chest pain
- Weakness
- Raised blood pressure
Rare 1 in 1,000 to 1 in 10,000
- High blood pressure, incl. hypertensive encephalopathy (severe headache and confusion), mainly after stopping suddenly
- Oversleeping
- Feeling generally unwell
Get help urgently if
- Fainting or a very slow pulse
- Chest pain or a racing, irregular heartbeat
- Severe drowsiness, especially if other sedating medicines were taken
Good to know
- Don’t stop suddenly. Blood pressure can rebound. The dose is reduced slowly.
- Swallow whole; don’t crush or chew. Avoid taking it with a high-fat meal, which raises how much is absorbed.
- Some medicines and grapefruit juice raise guanfacine levels. Check with your pharmacist.
- Blood pressure, pulse, height and weight are checked regularly.
Common questions
Is guanfacine a stimulant?
No. It’s a non-stimulant ADHD medicine and isn’t addictive. It can be used alone or added to a stimulant.
How long does guanfacine take to work?
It builds up over 2 to 4 weeks as the dose is increased, so it’s judged over weeks, not days.
What are the side effects of guanfacine?
Sleepiness, headache, tummy pain and tiredness are very common. Don’t stop it suddenly, as blood pressure can rebound.
Information only. Not a recommendation or endorsement of any product. Whether a medicine suits you depends on your health and other medicines, so talk to your doctor or pharmacist. In an emergency, call 000 (Australia) or your local emergency number. From a mobile, 112 works in most countries.
More information
- Australian Prescriber: Guanfacine for ADHD
- Healthdirect: Medicines information
- PBS: Guanfacine 1 mg
- NPS RADAR: Guanfacine for ADHD (PBS criteria and trial results)
maladywise.com/medicines/guanfacine/