Clonidine
Prescription ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
Clonidine is a centrally acting alpha-2 adrenergic agonist used for hypertension, including resistant hypertension, and for several off-label and approved indications such as ADHD, opioid and alcohol withdrawal symptoms, and menopausal hot flashes. It lowers blood pressure by reducing central sympathetic outflow, which decreases peripheral vascular resistance and heart rate. Abrupt discontinuation can cause dangerous rebound hypertension, so it must be tapered.
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What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
Clonidine is a centrally acting alpha-2 adrenergic agonist used for hypertension, including resistant hypertension, and for several off-label and approved indications such as ADHD, opioid and alcohol withdrawal symptoms, and menopausal hot flashes. NutriStack rates the supporting evidence as strong. Common adult dosing is Hypertension (immediate-release oral): start 0.1 mg twice daily, titrate to 0.2-0.6 mg/day in divided doses; max about 2.4 mg/day. Transdermal patch: 0.1-0.3 mg/day applied weekly. ADHD (Kapvay extended-release): 0.1 mg at bedtime, titrated weekly to a maximum of 0.4 mg/day in divided doses., though a prescriber sets the actual dose. This profile indexes 3 sources.
The bottom line
Evidence rating strong. Most-documented uses: hypertension, including resistant hypertension as add-on therapy, attention-deficit/hyperactivity disorder (extended-release formulation), management of opioid withdrawal autonomic symptoms. 3 sources indexed (1978–2012), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
Clonidine stimulates presynaptic alpha-2 adrenergic receptors in the brainstem vasomotor center (notably the nucleus tractus solitarius and locus coeruleus). Activating these autoinhibitory receptors reduces sympathetic nervous system outflow from the central nervous system, lowering norepinephrine release. The result is reduced peripheral vascular resistance, decreased heart rate, and lower blood pressure. The same central sympatholytic and locus coeruleus effects account for its sedative properties, its ability to blunt autonomic hyperactivity during opioid or alcohol withdrawal, and its modulation of attention and arousal in ADHD. Clonidine also has partial agonist activity at imidazoline receptors, which may contribute to its antihypertensive effect.2,1
Dosing & protocol.
Well absorbed orally with bioavailability around 75-100 percent; may be taken with or without food. Clonidine is lipophilic enough to cross the blood-brain barrier and is also delivered transdermally. Largest oral dose is often given at bedtime to limit daytime sedation.2
Full safety detail.
Side effects
- Drowsiness and sedation
- Dry mouth (xerostomia)
- Dizziness and lightheadedness
- Constipation
- Hypotension and orthostatic hypotension
- Bradycardia
- Fatigue and weakness
- Rebound hypertension on abrupt withdrawal
- Erectile dysfunction
- Localized skin irritation with transdermal patch
Contraindications
- Known hypersensitivity to clonidine or, for the patch, to components of the transdermal system1,2
- Caution with abrupt discontinuation due to risk of rebound hypertension; always taper2
- Severe bradyarrhythmia from sick sinus syndrome or second/third-degree AV block
- Use with caution in significant cardiovascular disease, cerebrovascular disease, chronic kidney disease, and in the elderly
- Additive CNS depression and sedation when combined with alcohol, sedatives, opioids, or other CNS depressants3
- Caution when combined with beta-blockers (worsened rebound on withdrawal) and with agents that slow AV conduction
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Randomized controlled trials
1- 1Clonidine in opiate withdrawalGold MS, Redmond DE, Kleber HD · Lancet · 1978
Clonidine suppressed many of the autonomic signs and symptoms of opioid withdrawal, consistent with reduced noradrenergic locus coeruleus activity.
Reference material
2- 2Catapres (clonidine hydrochloride) Prescribing InformationBoehringer Ingelheim Pharmaceuticals · US FDA Prescribing Information · 2012
Clonidine reduces blood pressure through central alpha-2 receptor stimulation and decreased sympathetic outflow; abrupt cessation can cause rebound hypertension, so the dose should be tapered over 2 to 4 days.
- 3Kapvay (clonidine hydrochloride extended-release) Prescribing InformationConcordia Pharmaceuticals · US FDA Prescribing Information · 2010
Extended-release clonidine, alone or as adjunct to stimulants, significantly reduced ADHD symptom scores versus placebo, with somnolence and sedation as the most common adverse effects.
Common questions.
Quick answers about Clonidine, drawn from the data on this page.
What is Clonidine?
Clonidine is a centrally acting alpha-2 adrenergic agonist used for hypertension, including resistant hypertension, and for several off-label and approved indications such as ADHD, opioid and alcohol withdrawal symptoms, and menopausal hot flashes. It lowers blood pressure by reducing central sympathetic outflow, which decreases peripheral vascular resistance and heart rate. Abrupt discontinuation can cause dangerous rebound hypertension, so it must be tapered.
What is Clonidine used for?
Commonly cited benefits of Clonidine include: Hypertension, including resistant hypertension as add-on therapy; Attention-deficit/hyperactivity disorder (extended-release formulation); Management of opioid withdrawal autonomic symptoms; Reduction of menopausal hot flashes; Adjunct for alcohol withdrawal and certain pain syndromes (epidural). NutriStack rates the overall evidence as strong.
What is a typical dose of Clonidine?
A typical adult dose of Clonidine is Hypertension (immediate-release oral): start 0.1 mg twice daily, titrate to 0.2-0.6 mg/day in divided doses; max about 2.4 mg/day. Transdermal patch: 0.1-0.3 mg/day applied weekly. ADHD (Kapvay extended-release): 0.1 mg at bedtime, titrated weekly to a maximum of 0.4 mg/day in divided doses.. The commonly recommended form is Oral immediate-release tablet for hypertension; transdermal patch for steadier levels and improved adherence; extended-release tablet for ADHD.. These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Clonidine?
Reported side effects include drowsiness and sedation, dry mouth (xerostomia), dizziness and lightheadedness, constipation, hypotension and orthostatic hypotension, bradycardia. This is educational information; check with a healthcare professional before use.
How strong is the evidence for Clonidine?
NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
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