Clonidine hydrochloride is a centrally acting alpha-2 adrenergic agonist, recognized for its efficacy in managing hypertension and attention-deficit/hyperactivity disorder (ADHD). It modulates sympathetic outflow from the central nervous system, leading to reduced peripheral vascular resistance, decreased heart rate, and lowered blood pressure. Its non-stimulant mechanism also makes it a valuable option for ADHD treatment in both children and adults, particularly when first-line therapies are unsuitable or poorly tolerated. Available in oral and transdermal formulations, it offers flexible dosing tailored to individual patient needs and clinical scenarios.

Features

• Active Ingredient: Clonidine hydrochloride
• Available Formulations: Oral tablets (0.1 mg, 0.2 mg, 0.3 mg) and transdermal therapeutic system (weekly patches: 0.1 mg/24h, 0.2 mg/24h, 0.3 mg/24h)
• Mechanism of Action: Selective agonist of central alpha-2 adrenergic receptors, reducing sympathetic nervous system activity
• Half-life: Approximately 12–16 hours (oral); steady delivery over 7 days (transdermal)
• Bioavailability: ~75–95% (oral); ~60–70% (transdermal, varies by patch size and skin site)
• Metabolism: Hepatic, primarily via CYP2D6; metabolites excreted renally (40–60% unchanged drug in urine)
• Onset of Action: 30–60 minutes (oral); 2–3 days to achieve therapeutic effect (transdermal)

Benefits

• Provides reliable reduction in systolic and diastolic blood pressure through central sympatholytic action
• Non-stimulant option for ADHD management, reducing hyperactivity and improving impulse control
• Transdermal formulation offers consistent drug delivery, improving adherence and minimizing peak-trough fluctuations
• May alleviate symptoms of opioid withdrawal, menopausal flushing, and Tourette syndrome
• Can be used as adjunctive therapy with other antihypertensives or psychostimulants for enhanced efficacy
• Lower abuse potential compared to stimulant medications for ADHD

Common use

Clonidine is primarily indicated for the management of hypertension, either as monotherapy or in combination with other antihypertensive agents. It is also FDA-approved for the treatment of attention-deficit/hyperactivity disorder (ADHD) in pediatric and adult populations. Off-label uses include management of opioid withdrawal symptoms, Tourette syndrome, menopausal hot flashes, and as an adjunct for pain management and anxiety. Its ability to reduce sympathetic tone makes it useful in conditions where autonomic hyperactivity is a feature.

Dosage and direction

Hypertension (Adults):
Initial dose: 0.1 mg orally twice daily; increase gradually by 0.1 mg/day at weekly intervals. Maintenance dose: 0.2–0.6 mg/day in divided doses. Maximum dose: 2.4 mg/day.
Transdermal: Apply one patch (0.1 mg/24h) once every 7 days; titrate after 1–2 weeks if needed.

ADHD (Children ≥6 years and Adolescents):
Initial dose: 0.05 mg orally at bedtime; increase by 0.05 mg/day every 3–7 days. Maintenance dose: 0.2–0.3 mg/day, divided into 2–4 doses. Maximum dose: 0.4 mg/day.
Doses should be tapered gradually upon discontinuation to avoid rebound hypertension.

Take oral tablets with or without food; do not crush or chew. Apply transdermal patch to a hairless, clean, dry area of intact skin on upper arm or torso; rotate application sites.

Precautions

Monitor blood pressure and heart rate regularly, especially during initiation and titration. Use with caution in patients with cardiovascular disease, cerebrovascular disease, or renal impairment. May cause sedation; advise against driving or operating machinery until response is known. Abrupt discontinuation can lead to rebound hypertension, tachycardia, and nervousness; taper dose over 2–4 days. Transdermal patch may cause skin irritation; if severe, discontinue use. Not recommended during pregnancy unless potential benefit justifies potential risk (Pregnancy Category C). Use in geriatric patients may require lower doses due to increased sensitivity.

Contraindications

Hypersensitivity to clonidine or any component of the formulation. Do not use in patients with sinus node dysfunction or severe bradycardia. Avoid in individuals with history of hypersensitivity reactions to adhesive layer of transdermal system.

Possible side effect

Common: Dry mouth, drowsiness, dizziness, sedation, constipation, fatigue.
Less common: Orthostatic hypotension, bradycardia, headache, nausea, sleep disturbances, vivid dreams.
Rare but serious: Severe hypotension, heart block, rebound hypertension, depression, allergic skin reactions (transdermal), hallucinations.
Most side effects are dose-dependent and may diminish with continued use.

Drug interaction

• CNS depressants (e.g., alcohol, benzodiazepines, opioids): Enhanced sedative effects.
• Beta-blockers: Increased risk of bradycardia and AV block; avoid concurrent withdrawal.
• Tricyclic antidepressants: May diminish antihypertensive effect.
• Calcium channel blockers, diuretics, other antihypertensives: Additive hypotensive effects.
• Levodopa, pramipexole: Potential for enhanced hypotensive effects.
• CYP2D6 inhibitors/inducers: May alter clonidine levels (e.g., fluoxetine, paroxetine).

Missed dose

If a dose is missed, take it as soon as remembered unless it is almost time for the next dose. Do not double the dose. For transdermal patch, apply a new patch as soon as possible if detachment or missed application occurs, and resume usual changing schedule.

Overdose

Symptoms: Profound hypotension, bradycardia, respiratory depression, hypothermia, drowsiness, weak or absent reflexes, seizures.
Management: Supportive care; administer IV fluids and vasopressors for hypotension. Atropine may be used for bradycardia. Tolazoline (an alpha-adrenergic blocker) has been used as an antidote but is not routinely available. Hemodialysis is not effective due to high protein binding.

Storage

Store at room temperature (20–25°C/68–77°F). Oral tablets: Protect from light and moisture. Transdermal patches: Keep in sealed pouch until use; discard used patches safely. Keep out of reach of children and pets.

Disclaimer

This information is for educational purposes and does not replace professional medical advice, diagnosis, or treatment. Always consult a healthcare provider before starting or changing any medication regimen. Individual response to clonidine may vary based on health status, concomitant medications, and other factors.

Reviews

“Clonidine has been a cornerstone in my practice for managing hypertensive patients who are not controlled on first-line agents. Its central action offers a unique mechanism, though sedation can be a limiting factor.” – Cardiologist, 15 years experience.
“As a child psychiatrist, I find clonidine invaluable for ADHD, especially in patients with comorbid tics or sleep disturbances. The transdermal option improves compliance in adolescents.” – Child Psychiatrist, 10 years experience.
“Effective for opioid withdrawal protocols, though requires careful monitoring for hypotension. A versatile drug with multiple applications beyond its labeled indications.” – Addiction Specialist, 8 years experience.