Clonidine

# Clonidine ## Overview - **Classification**: Centrally acting alpha-2 adrenergic agonist. - **Mechanism**: Stimulates presynaptic alpha-2 receptors in the brainstem, reducing sympathetic outflow from the central nervous system. This leads to decreased peripheral vascular resistance, heart rate, and blood pressure. ## Primary Indications 1. **Hypertension** - Management of high blood pressure. 2. **Attention-Deficit/Hyperactivity Disorder (ADHD)** - Extended-release formulation (Kapvay) for children ≥6 years and adolescents. 3. **Opioid Withdrawal** - Adjunctive therapy to manage symptoms. ## Adult Dosing ### Standard Dosing **Hypertension (Oral)** - **Dose**: Initially **0.1 mg**. - **Frequency**: Twice daily (BID). - **Route**: Oral. - **Titration**: Increase by **0.1 mg/day** every 1-2 weeks. - **Maximum Dose**: **2.4 mg/day** in divided doses. **Hypertension (Transdermal Patch)** - **Dose**: Apply **0.1 mg/24 hr** patch. - **Frequency**: Apply once every 7 days. - **Route**: Transdermal. - **Titration**: Increase to **0.2 mg/24 hr** or **0.3 mg/24 hr** weekly. **ADHD (Kapvay - Extended-Release Oral)** - **Dose**: Initially **0.1 mg**. - **Frequency**: At bedtime (HS) or divided BID. - **Route**: Oral. - **Titration**: Increase by **0.1 mg/day** weekly. - **Maximum Dose**: **0.4 mg/day**. **Opioid Withdrawal (Adjunct)** - **Dose**: **0.1-0.2 mg**. - **Frequency**: Every 4-6 hours as needed (PRN). - **Route**: Oral. - **Maximum Dose**: Up to **1.2 mg/day** (often inpatient). - **Special Considerations**: Monitor blood pressure (BP) closely due to hypotensive effects. ### Dose Adjustments - **Renal Impairment**: Start with lower doses (**0.05 mg BID** or **0.1 mg once daily**). Titrate cautiously; monitor BP and renal function. - **Hepatic Impairment**: No specific dose adjustments; use with caution. - **Elderly Patients**: Start with lower doses (**0.05 mg BID**); increased risk of hypotension, bradycardia, and CNS effects. Titrate slowly. ## Pediatric Dosing ### Neonates (0-28 days) - **Special Notes**: Not routinely recommended due to limited safety data. Use only if compelling indication, under specialist supervision with careful monitoring of vital signs. ### Infants (1-12 months) - **Special Notes**: Limited data; use with extreme caution under specialist guidance. Dosing is highly individualized (e.g., **0.005-0.01 mg/kg/dose**). Monitor closely for bradycardia/hypotension. ### Children (1-12 years) **Hypertension (Oral - Off-label)** - **Dose**: Initial **0.05-0.1 mg**. - **Frequency**: Once daily or BID. - **Route**: Oral. - **Titration**: Increase by **0.05 mg/day** weekly. - **Maximum**: **0.025 mg/kg/day** or **0.8 mg/day**, whichever is less. Max single dose **0.4 mg**. **ADHD (Kapvay - Extended-Release Oral, FDA-approved for children ≥6 years)** - **Dose (6-12 years)**: Initial **0.1 mg**. - **Frequency**: At bedtime (HS) or divided BID. - **Route**: Oral. - **Titration**: Increase by **0.1 mg/day** weekly. - **Maximum**: **0.4 mg/day**. ### Adolescents (13-18 years) - **Dose**: Generally follow **adult dosing** guidelines for the specific indication. - **Maximum**: **Adult maximum doses** apply. - **Considerations**: Start at the lower end of the adult dose range and titrate slowly, especially for younger adolescents. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to clonidine or any component. - **Absolute**: Transdermal patch in patients with scleroderma (severe local irritation). - **Relative**: Severe bradyarrhythmia, AV block, recent MI (use with caution, monitor closely). ### Common Adverse Effects - **Very Common (>10%)**: Dry mouth (xerostomia), **somnolence**, dizziness, sedation, fatigue, constipation. - **Common (1-10%)**: Nausea, vomiting, headache, orthostatic hypotension, local skin reactions (patch). - **Serious but Rare**: **Rebound hypertension** (upon abrupt discontinuation), severe bradycardia, AV block, syncope, depression. ### Key Drug Interactions - **CNS Depressants (e.g., alcohol, benzodiazepines, opioids)**: Increased sedation and CNS depression. Avoid co-administration or use caution. - **Beta-blockers, Calcium Channel Blockers, Digoxin**: Increased risk of bradycardia and AV block. Monitor heart rate (HR) and BP closely. - **Tricyclic Antidepressants (TCAs)**: May antagonize clonidine's hypotensive effect. Monitor BP. - **Other Antihypertensives**: Additive hypotensive effects. Monitor BP; dose adjustment may be needed. ## Monitoring & Follow-up - **Before Treatment**: Baseline blood pressure (BP), heart rate (HR). Assess for CNS depression and contraindications. - **During Treatment**: Monitor BP and HR regularly (especially during initiation and dose changes). Assess for CNS effects (drowsiness, dizziness). - **Clinical Signs**: Watch for signs of rebound hypertension if stopped abruptly, severe bradycardia, or mood changes. ## Clinical Pearls - 💡 **Abrupt Discontinuation**: NEVER discontinue clonidine abruptly. This can cause severe rebound hypertension. Taper dose slowly over 2-4 days or longer. - 💡 **First-Dose Sedation**: Sedation is most prominent with initial doses or dose increases. Consider administering the first dose at bedtime. - 💡 **Dry Mouth Management**: Advise patients to use sugar-free gum/lozenges or artificial saliva to alleviate xerostomia. - 💡 **Transdermal Patch Care**: Apply to a clean, dry, hairless area of the upper outer arm or chest. Rotate application sites weekly to minimize skin irritation. Remove before MRI. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.