Clonidine
An older blood pressure tablet that calms the body’s “fight or flight” signals. Now used more for ADHD, sleep and tics than for blood pressure.
Brand names
- Catapres
- Several generic brands sold as clonidine
How it works
Clonidine switches on alpha-2 receptors in the brainstem. This turns down adrenaline-type (sympathetic) signals, which 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
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.
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.
More information
maladywise.com/drugs/clonidine/