Clonidine

Generic name:

Clonidine

Drug class:

Alpha-2 adrenergic agonist

Dosage form:

Tablets (immediate-release), extended-release tablets, transdermal patch, injection solution

Route of administration:

Oral, transdermal, intravenous

Dose:

Hypertension: 0.1–0.2 mg twice daily, titrate to 2.4 mg/day max. ADHD (immediate-release): 0.1 mg at bedtime, increase to 0.4 mg/day. ADHD (extended-release): 0.1 mg/day, increase to 0.2 mg/day. Opioid withdrawal: 0.1–0.3 mg every 6–8 hours. Transdermal patch: 0.1–0.3 mg/day applied weekly. Varies by indication; consult label.

Mechanism of action:

Stimulates central alpha-2 adrenergic receptors, reducing sympathetic outflow, peripheral vascular resistance, heart rate, and blood pressure.

Drug usage cases:

• Essential hypertension (monotherapy or adjunct)
• Attention-deficit/hyperactivity disorder (ADHD), alone or adjunct to stimulants
• Opioid withdrawal symptom management
• Hot flashes
• Tourette’s syndrome (off-label)
• Migraine prophylaxis (off-label)
• Persistent hiccups (off-label)

Drug contraindications:

• Hypersensitivity to clonidine or formulation components
• Severe bradyarrhythmias
• Advanced heart block without pacemaker
• Severe coronary insufficiency
• Recent myocardial infarction (caution/contraindicated in some regimens)

Side effects:

• Drowsiness, sedation
• Dry mouth
• Bradycardia
• Hypotension
• Rebound hypertension upon abrupt withdrawal
• Constipation
• Fatigue, weakness
• Dizziness
• Headache
• Nightmares or vivid dreams
• Edema
• Impotence
• Skin irritation (transdermal)

Warnings:

• Abrupt discontinuation can cause severe rebound hypertension; taper gradually over 2–4 days
• Use caution in patients with cerebrovascular disease
• Monitor blood pressure and heart rate during therapy
• Risk of orthostatic hypotension; advise patients to rise slowly
• Potential for depression or mood changes; monitor mental status
• Enhanced sedation with other CNS depressants
• Dosage adjustment may be necessary in renal impairment

Use during pregnancy or breastfeeding:

Pregnancy: FDA category C. Animal studies show adverse effects; human data limited. Use only if clearly needed, with close monitoring of maternal blood pressure and fetal well-being. Breastfeeding: Excreted in breast milk; monitor infants for hypotension, bradycardia, drowsiness. Consider dose timing or alternative treatment if risk outweighs benefit.