Quick facts

  • Active ingredient: clonidine
  • Main condition: high blood pressure (hypertension)
  • Common US strengths: 0.1 mg tablets (also 0.2 mg and 0.3 mg); transdermal patches delivering 0.1 mg, 0.2 mg, or 0.3 mg per day

What clonidine is used for

Clonidine is an alpha-2 adrenergic agonist that lowers blood pressure by reducing sympathetic outflow from the brainstem. The result is decreased heart rate, peripheral vascular resistance, and renal vascular tone.

Primary approved use: control of high blood pressure. In practice, it may be prescribed alone or alongside other antihypertensives. Some clinicians also use it off-label for conditions such as hot flashes, withdrawal symptoms (for example, opioids), sleep problems related to hyperarousal, or ADHD, but these uses should be guided by a prescriber. For dosing details, see Dosing and how to take.

Dosing and how to take

Only use clonidine if it was prescribed for you. The regimen is individualized based on blood pressure response and tolerability.

Tablets

Oral clonidine is often taken twice daily. Many patients start at 0.1 mg at bedtime, then 0.1 mg twice daily, with cautious titration as needed. Your prescriber will set the schedule. Do not change your dose without medical advice and do not stop suddenly due to the risk of rebound hypertension. If you are also on a beta-blocker, special care is needed when making any changes (see Drug interactions).

Transdermal patches

Apply one patch to clean, dry, hairless skin on the upper outer arm or chest and replace every 7 days. Rotate sites with each new patch. Press firmly for 10-15 seconds, especially around the edges. If a patch loosens, you may use the supplied cover overlay or replace it per the product instructions. Do not cut patches.

Tip: remove the old patch before applying a new one. Choose a new area for each change to reduce skin irritation. For more safety notes, see Precautions and warnings.

Precautions and warnings

Clonidine can cause drowsiness, dizziness, and impaired reaction time. Avoid alcohol, and use extra caution with driving or tasks that require alertness, especially at the start of therapy or after dose changes.

  • Kidney concerns: dose adjustments may be required in renal impairment. Your clinician may monitor kidney function.
  • MRI warning for patches: some patches contain metal. Remove before MRI to prevent skin burns.
  • Do not stop abruptly: sudden discontinuation can cause severe rebound high blood pressure and fast heart rate.
  • Pregnancy and lactation: discuss risks and benefits with your prescriber.
  • Older adults: may be more sensitive to blood pressure drops and sedation.

Who should not use it

Avoid clonidine if you are allergic to clonidine or any component of the formulation. Extra caution or alternative therapy may be required for the following:

  • Bradycardia or sick sinus syndrome
  • Second- or third-degree atrioventricular block
  • Acute myocardial infarction or unstable coronary disease
  • Raynaud phenomenon or severe peripheral vascular disease
  • Severe depressive disorders
  • Significant kidney impairment

These factors should be reviewed with your clinician before starting therapy. For interaction risks that may mimic contraindications, see Drug interactions.

Possible side effects

Get emergency help for signs of a serious allergic reaction, such as hives, swelling of the face or throat, or trouble breathing. Other side effects can occur. Not everyone experiences these, but monitor for the following and contact a clinician if severe or persistent:

  • Very slow heart rate or episodes of fainting
  • Rapid weight gain, swelling in legs or ankles
  • Confusion, hallucinations, or unusual drowsiness
  • Fast or pounding heartbeat
  • Fever or paleness
  • Reduced urination
  • Skin irritation at the patch site if using transdermal form
  • Dry mouth, constipation, or dizziness

Drug interactions

Clonidine can interact with many medicines and substances. Always inform your healthcare team about everything you take, including over-the-counter items and supplements.

  • CNS depressants: alcohol, opioids, benzodiazepines, and barbiturates may increase sedation and dizziness.
  • Tricyclic antidepressants and some other antidepressants (for example, mirtazapine): may reduce clonidine effectiveness.
  • Beta-blockers: combined use may increase the risk of bradycardia; if discontinuing therapy, prescribers generally stop the beta-blocker first, then taper clonidine to reduce rebound hypertension risk.
  • Cyclosporine: concurrent use may increase cyclosporine levels and kidney toxicity risk.
  • Other blood pressure medicines: additive effects may occur; dosing may need adjustment.

Missed dose

Tablets: take the missed dose as soon as you remember unless it is close to the next scheduled dose. If it is almost time for the next dose, skip the missed dose. Do not double doses.

Patches: if a patch falls off or you forget to replace it on time, apply a new patch as soon as possible and then continue on your regular weekly schedule. If unsure how to adjust, contact your pharmacist or prescriber.

Overdose

Symptoms may include a period of very high blood pressure with headache or visual changes, followed by low blood pressure, slow heart rate, extreme drowsiness, cold skin, or fainting. Call emergency services right away if an overdose is suspected.

Storage and handling

  • Store tablets and patches at room temperature, ideally 20-25 C (68-77 F); brief excursions 15-30 C (59-86 F) are generally acceptable. Protect from moisture and light.
  • Keep out of reach of children and pets.
  • Patches: after removal, fold adhesive sides together and discard safely.

Similar medicines and alternatives

Clonidine is one of several options for blood pressure control and symptom management.

Medicines with a similar mechanism

  • Guanfacine: another central alpha-2 agonist; often causes less sedation; used for hypertension and ADHD. Extended-release forms are common for ADHD.
  • Methyldopa: central agent historically used in pregnancy-related hypertension; more sedating and with different side effect profile.

Other common antihypertensives

  • ACE inhibitors (for example, lisinopril): first-line for many patients; cough and high potassium are possible.
  • ARBs (for example, losartan): similar benefits to ACE inhibitors with lower cough risk.
  • Thiazide diuretics (for example, hydrochlorothiazide, chlorthalidone): effective and inexpensive; can lower potassium.
  • Calcium channel blockers (for example, amlodipine): effective for systolic hypertension; may cause ankle swelling.
  • Beta-blockers (for example, metoprolol): not usually first-line for uncomplicated hypertension but useful with coronary disease or certain arrhythmias.

Choice depends on other medical conditions, tolerability, and cost. Discuss options with your clinician. For price comparisons, see Typical prices in USD.

Typical prices in USD

Approximate out-of-pocket retail prices in the USA vary by pharmacy, region, and insurance. Discount programs can significantly reduce costs.

  • Clonidine tablets (generic, 0.1 mg): about $4-$15 for 30 tablets; $8-$25 for 60 tablets.
  • Clonidine tablets (generic, 0.2-0.3 mg): often $6-$20 for 30 tablets depending on strength.
  • Transdermal clonidine patches (generic or brand Catapres-TTS): roughly $50-$150 for a 4-week supply, depending on dose and brand.
  • Alternatives:
    • Lisinopril or losartan (generic): often $4-$15 for a 30-day supply.
    • Amlodipine (generic): about $4-$12 per month.
    • Hydrochlorothiazide or chlorthalidone: typically $4-$10 per month.
    • Guanfacine (immediate-release): variable, often $10-$30 per month; extended-release for ADHD is higher.

These are rough ranges to help with planning and are not offers. Check your local pharmacy for current pricing.

Additional practical tips

  • If you experience new chest pain, fainting, sudden severe headache, or vision changes, seek urgent care.
  • For skin reactions to patches, rotating sites and using the overlay can help; report severe dermatitis to your prescriber.
  • If affordability is a concern, ask about generic options, discount cards, or alternative first-line medicines with similar blood pressure benefits.

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Important disclaimer

The information on this page is general and does not include all possible directions, interactions, or precautions. It is not a substitute for professional medical advice, diagnosis, or treatment. Always follow the instructions provided by your healthcare provider and your prescription label. We do not guarantee accuracy, completeness, or timeliness and are not responsible for any harm resulting from use of this information or self-treatment.