A centrally-acting medicine (blood pressure, menopause, ADHD and more)
Clonidine
An older medicine with several uses — high blood pressure, menopausal hot flushes, ADHD and tics, and some pain and withdrawal settings — which must not be stopped suddenly.
What is Clonidine?
Clonidine acts on the brain to reduce nervous-system "drive", which lowers blood pressure and heart rate. It has a range of uses beyond blood pressure — reducing menopausal hot flushes, treating ADHD and tics (especially in children), and helping in some pain and withdrawal situations. Its key safety point is that it must never be stopped abruptly, because this can cause a sharp rebound rise in blood pressure.
Education and reference only. This is a plain-language guide to Clonidine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Clonidine is a long-established medicine that works through the brain to calm the sympathetic ("fight-or-flight") nervous system. Although newer drugs have replaced it as a first-choice blood-pressure treatment, it remains useful across several conditions: lowering blood pressure (including some difficult cases), reducing menopausal hot flushes and flushing, treating attention deficit hyperactivity disorder (ADHD) and tic disorders (often in children, under specialist care), and assisting in certain pain, anaesthetic and withdrawal settings. It is taken as a tablet (and, in some countries, a patch).
How it works
Clonidine stimulates particular receptors (alpha-2 receptors) in the brainstem that act as a "volume control" on the sympathetic nervous system. Turning this control down reduces the nerve signals that tighten blood vessels and speed the heart, so blood pressure and heart rate fall. The same calming of nervous-system activity underlies its other uses — steadying the temperature-regulating response in hot flushes, and reducing over-arousal and impulsivity in ADHD and tics.
What it treats
Conditions Clonidine is used for
Practical use
How to take Clonidine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it regularly as prescribed and never stop suddenly — it must be reduced gradually to avoid a rebound rise in blood pressure.
- Expect drowsiness and a dry mouth, especially early on; take care with driving until you know how it affects you.
- Rise slowly from sitting or lying to avoid dizziness.
- Do not miss doses; if you run low, get a repeat in good time rather than stopping.
- For children with ADHD or tics, follow the specialist’s monitoring plan (heart rate and blood pressure).
Weighing it up
Advantages & disadvantages of Clonidine
Advantages
- Versatile — useful in blood pressure, menopausal flushing, ADHD, tics and some pain/withdrawal settings.
- A non-hormonal option for hot flushes.
- Long established and inexpensive.
Disadvantages
- Must never be stopped abruptly (rebound high blood pressure).
- Commonly causes drowsiness, dry mouth and dizziness.
- Largely superseded as a first-line blood-pressure treatment.
Practical use
Good to know
The most important safety point with clonidine is never to stop it suddenly: abruptly stopping (or missing several doses) can cause a rebound surge in blood pressure, sometimes with headache, agitation and a racing heart — so it is always reduced gradually. Drowsiness and a dry mouth are common, especially at first, and it can cause dizziness on standing. When used for ADHD or tics in children, it is started and supervised by a specialist, with attention to heart rate and blood pressure. Because it is sedating, it interacts with alcohol and other sedating medicines.
Who should not take it / use with caution
- People with certain slow heart rhythms or significant heart-conduction problems.
- Used with care in depression (it can lower mood), significant heart or circulation disease, and kidney impairment.
- Pregnancy and breastfeeding — considered individually, on medical advice.
Monitoring
- Blood pressure and heart rate
- Mood and alertness
- In children (ADHD/tics), regular heart-rate and blood-pressure checks
Side effects
- Common: drowsiness, dry mouth, dizziness (including on standing), and constipation.
- Sometimes low mood, disturbed sleep, or a slow heart rate.
- Rebound high blood pressure if stopped suddenly.
Key interactions
- Alcohol and other sedating medicines add to drowsiness.
- Beta-blockers can worsen the rebound effect if clonidine is stopped, and add to heart-rate slowing; tricyclic antidepressants can reduce its blood-pressure effect.
- Other blood-pressure-lowering medicines add to its effect.
Available as: Tablets (different strengths for different uses); patches are available in some settings.
Answers
Clonidine: frequently asked questions
Why can’t I stop clonidine suddenly?
Stopping clonidine abruptly — or missing several doses — can cause a sharp rebound rise in blood pressure, sometimes with headache, agitation and a pounding heart. It is always reduced gradually under guidance. Make sure you don’t run out, and get repeat prescriptions in good time.
Can clonidine help with menopausal hot flushes?
Yes — clonidine is one of the non-hormonal options used to reduce the frequency and severity of menopausal hot flushes and flushing, which can suit women who cannot or prefer not to take HRT. It does not work for everyone, and drowsiness or dry mouth can limit it; your doctor can help weigh it against other options.
Is clonidine used for children?
Yes — under specialist supervision, clonidine is used for ADHD and for tic disorders (such as Tourette’s) in children, particularly where other treatments are unsuitable. It is started carefully with monitoring of heart rate and blood pressure, and must not be stopped suddenly.
Will clonidine make me drowsy?
Often, especially at first — drowsiness and a dry mouth are among its commonest effects, though they may ease with time. Take care with driving or operating machinery until you know how it affects you, and avoid alcohol, which adds to the drowsiness.
Authoritative sources
- BNF: Clonidine hydrochloride.
- electronic Medicines Compendium (SmPC): Clonidine.
- NICE NG87: ADHD; NG23: Menopause.
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