Clonidine
An old blood pressure tablet that turns down the body’s “fight or flight” signals. Now used more for ADHD, getting to sleep and tics than for blood pressure.
Quick answer: Clonidine is an older blood pressure tablet, now used more for ADHD, trouble getting to sleep with ADHD, tics and menopausal hot flushes. Common side effects are dizziness, drowsiness, light-headedness on standing and a dry mouth. It isn’t approved for insomnia, and the evidence for sleep is weak. Never stop it suddenly: your doctor will reduce it slowly.
At a glance
- For
- ADHD (often for sleep onset or added to a stimulant), tics, hot flushes, withdrawal, blood pressure
- Works
- ADHD: a modest benefit, smaller than stimulants; may help some children fall asleep faster (evidence limited). Blood pressure: effective but rarely first choice
- Cost
- $25 a script on the PBS ($7.70 concession)
- Kicks in
- Drowsiness within an hour or two; ADHD benefit builds over 2–4 weeks
- Taken for
- Months to years, reviewed regularly
- Watch for
- Drowsiness, dizziness on standing, dry mouth, constipation, low blood pressure
Stop it suddenly and blood pressure bounces back with interest. Always taper.
Brand names
- Catapres
- Several generic brands sold as clonidine
How it works
Clonidine switches on alpha-2 receptors in the brainstem, turning down adrenaline-type signals. That lowers blood pressure and heart rate and has a calming, sedating effect.
Used for
- High blood pressure (now rarely a first choice)
- ADHD, and trouble getting to sleep with ADHD, usually in children and started by a specialist (off-label in Australia)
- Tics and Tourette syndrome (off-label)
- Menopausal hot flushes
- Easing withdrawal from opioids or alcohol, under supervision (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
- Dizziness
- Drowsiness or sedation
- Light-headedness on standing (low blood pressure)
- Dry mouth
Common 1 in 10 to 1 in 100
- Low mood
- Sleep problems
- Headache
- Constipation
- Nausea or vomiting
- Pain in the salivary glands
- Erection problems
- Tiredness
Uncommon 1 in 100 to 1 in 1,000
- Delusions or seeing things that aren’t there
- Nightmares
- Pins and needles
- Slow heart rate
- Cold, pale fingers (Raynaud’s)
- Itch, rash or hives
- Feeling generally unwell
Rare 1 in 1,000 to 1 in 10,000
- Breast swelling in men
- Heart block (an electrical problem causing a very slow pulse)
- Dry eyes or a dry nose
- Severe bowel slow-down (colonic pseudo-obstruction)
- Hair loss
- Raised blood sugar
Frequency not known reported, rate unclear
- Confusion
- Lower sex drive
- Blurred near vision
- Slow or irregular heart rhythm
Get help urgently if
- Fainting, a very slow pulse or feeling very faint
- Extreme sleepiness or slowed breathing
- A child swallows any tablets not meant for them: even one can be dangerous. Call 000 or the Poisons Information Centre on 13 11 26
Good to know
- Don’t stop suddenly. Blood pressure can rebound and cause agitation, headache and a racing heart. Your doctor will reduce it slowly.
- Alcohol, sleeping tablets and other sedating medicines add to the drowsiness.
- Take care driving until you know how it affects you.
- Store locked away from children. Even one tablet can be dangerous to a child.
Common questions
What is clonidine used for?
It’s an older blood pressure tablet, now used more for ADHD and trouble getting to sleep with ADHD (off-label, usually started by a specialist), tics, and menopausal hot flushes. Its ADHD effect is modest, smaller than stimulants.
What are the common side effects of clonidine?
Dizziness, drowsiness, light-headedness on standing and a dry mouth are very common. Take care driving until you know how it affects you.
Can I stop clonidine suddenly?
No. Blood pressure can rebound and cause agitation, headache and a racing heart. Your doctor will reduce it slowly.
Does clonidine help with sleep?
Clonidine isn’t approved for insomnia. It causes drowsiness, and specialists sometimes use it off-label to help children with ADHD fall asleep, but the evidence is weak (mainly small case series). There is no good evidence for it as a sleeping tablet in adults, and it can cause low blood pressure, dizziness and rebound if stopped suddenly. For ongoing insomnia, CBT for insomnia (CBT-I) has the best evidence.
What is Catapres 100 used for?
Catapres 100 is a brand of clonidine hydrochloride 100 microgram tablets (there is also Catapres 150). Its main approved use is high blood pressure; the consumer leaflet also lists preventing migraine and easing menopausal flushing. Doctors also use clonidine off-label for ADHD, sleep onset with ADHD, tics and withdrawal symptoms.
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
- Catapres product information
- Healthdirect: Medicines information
- PBS: Clonidine tablets
- Review: Drugs for insomnia in children with ADHD (Paediatric Drugs, 2017)
maladywise.com/medicines/clonidine/