- See Alpha Adrenergic Central Agonist
- See Alpha Adrenergic Receptor
- Central Acting Adrenergic Agonists
- Activates alpha-2 receptors that inhibit CNS preganglionic sympathetic signals, lowering Blood Pressure
- Results in increased parasympathetic effects and side effects (e.g. sedation)
- Renal excretion (unchanged in urine)
- Decrease dose in Renal Insufficiency, including starting dose
- Observe for adverse effects (Bradycardia, Hypotension)
- Oral Dosing
- Readily absorbed with 70% Bioavailability
- Activity
- Onset in 30-60 min
- Duration: 6-10 hours
- See Clonidine Withdrawal
- Acute withdrawal risk with rebound Hypertension
- Do not stop suddenly (esp. if Clonidine dose >1.2 mg per day)
- Medications
-
Clonidine (Catapres) Tablet
-
Hypertension (adults)
- Start 0.1 mg orally twice daily
- Titrate dose weekly, modifying total daily dose 0.1 mg/day to typical dose of 0.2 to 0.6 mg/day divided twice daily
- Maximum total daily dose: 2.4 mg/day
-
Hypertensive Urgency (adults, other agents are preferred for Hypertensive Urgency )
- Start: 0.2 mg oral load
- Titrate 0.1 mg/hour to:
- Maximum of 0.7 mg
- Diastolic Blood Pressure drops more than 20 mmHg
-
Hypertension (children)
- Start 5 to 7 mcg/kg/day orally divided every 6 to 12 hours
- Titrate dose weekly, modifying total daily dose 5-25 mcg/kg/day in divided doses (maximal dose 0.9 mg/day)
-
Hot Flushes
- Start 0.1 mg orally at bedtime (or transdermal patch)
- May titrate up to 0.2 mg orally twice daily
- Medications
-
Clonidine Transdermal Patch (Catapress-TTS)
- Not recommended for use in children
- Available in 0.1, 0.2 and 0.3 mg/day patches (may combine patches up to two of the 0.3 mg/day patches)
- Start with a 0.1 mg/day patch
- Titrate to effective dose, up to maximum effective dose of 0.6 mg/day (two of the 0.3 mg/day patches)
- Costs $40-100/month (depending on dose)
- Changed every 7 days
- Does not reach peak effect for 2-3 days
- Once at level, delivers constant Clonidine rate over 7 days
- Transition from oral to patch
- Day 1
- Apply transdermal Clonidine
- Take full oral Clonidine dose
- Day 2
- Take 50% of oral Clonidine dose
- Day 3
- Take 25% of oral Clonidine dose
- Discontinue oral Clonidine
- Clonidine IV
- Epidural Clonidine (for Chronic Pain)
- Pregnancy Category C
- Unknown Safety in Lactation
- See Clonidine Overdose
- See Alpha Adrenergic Central Agonist
-
Somnolence
-
Headache
-
Dry Mouth
-
Constipation
-
Bradycardia
- Risk of Sinus Node Dysfunction and Atrioventricular Block
- Increased risk when combined with Digoxin, Beta Blockers, nondihydropyridine Calcium Channel Blockers
-
Hypotension
- Rebound Hypertension (if abruptly discontinued at higher dose)
- See Clonidine Withdrawal
- Risk increases with total daily doses >0.7 mg/day (esp. >1.2 mg/day)
- Slowly taper dose every 3 to 7 days to prevent rebound Hypertension
- Continue in Clonidine in the perioperative period
-
Sodium and water retention
- Reflex renin release in response to excessive Clonidine and renal hypoperfusion
- (2020) Med Lett Drugs Ther 62(1598): 73-80
- Mishler and Lovecchio (2017) Crit Dec Emerg Med 31(11): 15-20
- Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 64-5
loading