Clonidine ER (Kapvay)

What it treats

Clonidine ER is approved by the U.S. Food and Drug Administration for ADHD in children and adolescents ages 6 to 17, either as monotherapy or as adjunctive therapy to a stimulant. Immediate-release clonidine (Catapres, generic) is approved for hypertension and is used off-label for other purposes such as opioid withdrawal and PTSD hyperarousal; this page focuses on Kapvay for ADHD.

The typical clinical situation where clonidine ER helps most: a child with ADHD whose hyperactivity, impulsivity, or sleep-onset difficulty isn't fully addressed by a stimulant, or a child who cannot tolerate a stimulant.

How it works

Clonidine activates alpha-2 adrenergic receptors in the brain. In the prefrontal cortex, that helps regulate attention, working memory, and impulse control. In the arousal system, it produces a calming effect and reduces overactive stress signaling. Peripherally, alpha-2 activation lowers blood pressure and heart rate (which is why immediate-release clonidine is a blood pressure medication).

The extended-release formulation smooths out the peaks and troughs, which reduces some of the sedation and blood pressure swings seen with immediate-release clonidine.

Receptor mechanism (detail)

Clonidine is a central alpha-2A adrenergic receptor agonist. Prefrontal cortex alpha-2A activation strengthens the working memory and executive function circuits that are underactive in ADHD. Downregulating norepinephrine outflow from the locus coeruleus reduces arousal, which is where the sedative and antihypertensive effects come from. Guanfacine is more selective for alpha-2A than clonidine, which is why guanfacine tends to be less sedating.

Potency and typical dosing pattern

Ranges are typical framework only, not a prescription for any individual.

Clonidine ER: 0.1 mg at bedtime starting. Titrate weekly in 0.1 mg increments to 0.1 mg twice daily, then 0.2 mg AM and 0.1 mg PM, then 0.2 mg twice daily, up to a maximum of 0.4 mg per day divided. Bedtime dose is often higher than morning dose to use the sedation as part of sleep onset.

Half-life is about 12 to 16 hours.

Safety monitoring

• Blood pressure and heart rate at baseline and at each visit. Alpha-2 agonists lower both.
• Sedation. Common, especially at initiation and dose changes.
• Do not stop abruptly. Sudden discontinuation can cause rebound hypertension, sometimes serious. Taper over 3 to 7 days minimum.
• ECG. Baseline ECG is reasonable, especially with cardiac history or family history of arrhythmia.
• Avoid combining with other antihypertensives without careful oversight.
• Skin. No transdermal formulation is approved for ADHD; the Catapres transdermal patch is for hypertension.

What to expect

Common side effects

• Sedation and daytime sleepiness.
• Dry mouth.
• Fatigue.
• Constipation.
• Dizziness, particularly on standing.
• Irritability, occasional.
• Reduced appetite, less common than with stimulants.

If sedation is limiting, dose reduction, timing changes, or slower titration usually help. Talk with the prescriber.

Serious side effects and warnings

• Rebound hypertension. The most important warning. Abrupt discontinuation, particularly after weeks of use, can cause a sharp rise in blood pressure, sometimes with agitation, tremor, and headache. Always taper.
• Bradycardia and hypotension. Excessive drops in heart rate and blood pressure, more likely at higher doses or in combination with other cardiovascular medications.
• Syncope. Fainting, especially on standing.
• AV block, rare.
• Skin reactions, uncommon.
• Sedation compounding with other CNS depressants (opioids, alcohol, sedatives).

Sexual side effects

Clonidine can occasionally cause reduced libido or erectile difficulty in adults, though this is less relevant to pediatric ADHD use. If a change occurs, mention it to a prescriber.

Weight, appetite, and sleep

Clonidine doesn't typically cause the weight loss that stimulants do. It often helps with sleep-onset difficulty, particularly the delayed sleep pattern common in ADHD.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual. The right dose is a decision for a prescriber.

Kapvay comes as extended-release tablets in 0.1 mg and 0.2 mg strengths. Divided doses across the day are typical. Kapvay is not interchangeable with immediate-release clonidine on a milligram-for-milligram basis.

Missed doses and interactions

If a dose is missed, take it when remembered unless it's close to the next dose. Don't double up. Notably, missing several doses in a row can trigger rebound hypertension, so a plan for restarts (or a formal taper if stopping) is important.

Combining with other CNS depressants (opioids, alcohol, sedatives) increases sedation and hypotension risk. Combining with other blood-pressure-lowering medications compounds the effect. Give every prescriber and pharmacist the full medication list.

Stopping and tapering

Clonidine ER must be tapered, not stopped abruptly. The taper reduces total daily dose by no more than 0.1 mg every 3 to 7 days depending on how long it's been used. If a dose is stopped abruptly (a run-out, a hospital admission, a switch), the prescriber should be alerted quickly so blood pressure can be monitored.

Pregnancy and breastfeeding

Individual circumstances matter, and the decision belongs with a clinician. Anyone pregnant, planning a pregnancy, or breastfeeding should discuss it with their prescriber.

Cost and generic availability

Clonidine ER (Kapvay) is available as a generic. Immediate-release clonidine has been generic for decades and is very inexpensive; the ER form is more expensive but generally covered by insurance for ADHD.

Common questions

How is Kapvay different from Intuniv (guanfacine)? Both are alpha-2 agonists used for ADHD in children. Guanfacine is more selective for the alpha-2A subtype, which tends to make it less sedating and less prone to blood pressure drops. Clonidine's stronger sedative profile can be useful if sleep-onset difficulty is a target.

Is Kapvay the same as the clonidine patch or Catapres tablets? Not quite. Kapvay is extended-release clonidine designed for ADHD. Catapres tablets are immediate-release and dosed differently. The transdermal patch is for hypertension. They shouldn't be swapped 1-for-1.

Is it a controlled substance? No. Clonidine ER is not a controlled substance and can be refilled the usual way.

What if I stop it suddenly? Blood pressure can rebound to dangerous levels. Taper under a prescriber's supervision.

Can it be combined with a stimulant? Yes, and that's a common use case. Kapvay is approved as adjunct to stimulant therapy.

Questions to ask your prescriber

• Is Kapvay the right non-stimulant for my (or my child's) situation?
• How will we monitor blood pressure and heart rate?
• What should we do if a dose is missed?
• How will we taper it if we ever stop?
• If we're combining with a stimulant, how do the doses interact?

Sources

This guide draws on current prescribing information and public health references and current as of June 8, 2026. It is reviewed for clinical accuracy and updated as guidance changes.

• U.S. Food and Drug Administration. Clonidine ER (Kapvay) prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Clonidine.
• American Academy of Pediatrics. ADHD Clinical Practice Guideline.
• American Psychiatric Association. Practice guidance on ADHD in adults.