clonidine hydrochloride at a glance
Medicine class
Centrally acting alpha-2 adrenergic agonist.
Licensed roles vary
Uses depend on the product and include migraine prevention, menopausal flushing, hypertension and hypertensive crises.
What is clonidine hydrochloride used for?
The licensed indication depends on the formulation.
Selected tablets and lower-concentration oral solution: migraine prevention and menopausal flushing.
Selected higher-concentration oral solution: essential and secondary hypertension.
Injection: hospital treatment of hypertensive crises.
Specialists sometimes use clonidine in non-licensed contexts including ADHD, tic disorders, sleep problems and some movement disorders.
How does clonidine hydrochloride work?
Clonidine stimulates alpha-2 receptors in the brain, reducing sympathetic nerve output and increasing vagal influence. This can slow the heart rate and lower blood pressure; altered vascular responses may also reduce migraine-related changes and menopausal flushing.
clonidine hydrochloride preparations and strengths
Oral solution
Route: Oral
Strengths: 50 micrograms/5 mL, 100 micrograms/5 mL
Tablet
Route: Oral
Strengths: 25 micrograms
Injection
Route: Parenteral
Strengths: 150 micrograms/mL
How to take clonidine hydrochloride
Follow the prescription and product leaflet because formulations have different concentrations and licensed uses.
Swallow tablets with water, with or without food.
Measure oral solution with the supplied oral syringe or measuring device, not a kitchen teaspoon.
Injection is administered by healthcare professionals in hospital.
Do not stop clonidine abruptly without prescriber guidance.
clonidine hydrochloride side effects
Common or expected effects
- Sleepiness, sedation or fatigue
- Dizziness, including on standing
- Dry mouth
- Constipation, nausea or vomiting
- Headache
- Sleep disturbance or depression
- Erectile dysfunction
Get urgent medical advice
- Severe allergic reaction
- Very slow or irregular heartbeat, or fainting
- Severe confusion or hallucinations
- Abdominal pain with vomiting and constipation
- Marked breathing difficulty, reduced consciousness or collapse, particularly after overdose
clonidine hydrochloride in pregnancy
Clonidine is generally not recommended during pregnancy because human safety information is limited. A prescriber should assess alternatives and the risks of untreated disease. Do not stop it abruptly if it is controlling blood pressure. Product information notes placental transfer and possible effects on fetal heart rate.
clonidine hydrochloride while breastfeeding
Product information does not recommend clonidine during breastfeeding because it enters milk and evidence in infants is limited. NHS advice says it may sometimes be considered after individual assessment, although alternatives may be preferred for a premature baby. Seek advice if the baby feeds poorly, is unusually sleepy or appears unusually pale.
clonidine hydrochloride interactions
Tell the prescriber or pharmacist about all medicines, supplements and herbal products. Important examples include:
Other antihypertensives, vasodilators and diuretics
May increase blood-pressure lowering, dizziness or fainting.
Beta blockers, verapamil, diltiazem or digoxin
May slow the heartbeat or worsen conduction problems. Withdrawal requires clinical planning when a beta blocker is involved.
Common questions about clonidine hydrochloride
Answers are fully visible for fast scanning and source review.
Can clonidine hydrochloride be stopped suddenly?
No. Sudden withdrawal can rapidly raise blood pressure and cause palpitations, agitation, tremor, headache or nausea. Plan stopping with the prescriber.
Can clonidine hydrochloride make you sleepy?
Yes. Sleepiness, sedation and fatigue are recognised effects.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.