clonidine hydrochloride
clonidine
clonidine hydrochloride
Pharmacologic class: Centrally acting sympatholytic
Therapeutic class: Antihypertensive
Pregnancy risk category C
FDA Box Warning
• Before use, dilute clonidine hydrochloride 500-μg/mL strength product in appropriate solution.
• Epidural form (clonidine hydrochloride) isn't recommended for obstetric, postpartum, or perioperative pain management. In these cases, risk of hemodynamic instability may be unacceptable, except in rare patients for whom potential benefits may outweigh possible risks.
Action
Stimulates alpha-adrenergic receptors in CNS, decreasing sympathetic outflow, inhibiting vasoconstriction, and ultimately reducing blood pressure. Also prevents transmission of pain impulses by inhibiting pain pathway signals in brain.
Availability
Solution for epidural injection: 100 mcg/ml in 10-ml vials, 500 mcg/ml in 10-ml vials
Tablets: 100 mcg (0.1 mg), 200 mcg (0.2 mg), 300 mcg (0.3 mg)
Transdermal systems: 2.5 mg total released as 0.1 mg/24 hours (TTS 1), 5 mg total released as 0.2 mg/24 hours (TTS 2), 7.5 mg total released as 0.3 mg/24 hours (TTS 3)
Indications and dosages
➣ Mild to moderate hypertension
Adults: 0.1 mg P.O. b.i.d. (morning and bedtime) alone or with other anti-hypertensives; increase in increments of 0.1 mg/day q week until desired response occurs. Or, one transdermal system applied once q 7 days to hairless area of intact skin on upper outer arm or chest.
➣ Severe pain in cancer patients unresponsive to opioids alone
Adults: Initially, 30 mcg/hour by continuous epidural infusion, titrated upward or downward depending on patient response
Dosage adjustment
• Renal impairment
Off-label uses
• Acute alcohol withdrawal
• Akathisia
• Diarrhea
• Prolonged surgical anesthesia
Contraindications
• Hypersensitivity to drug
• Hypersensitivity to components of adhesive layer (transdermal form)
• Infection at epidural injection site, bleeding problems (epidural use)
• Concurrent anticoagulant therapy
Precautions
Use cautiously in:
• renal insufficiency, serious cardiac or cerebrovascular disease
• elderly patients
• pregnant or breastfeeding patients.
Administration
• For epidural use, dilute drug solution in normal saline solution, as ordered.
• To minimize sedative effects, give largest portion of maintenance P.O. dose at bedtime.
Adverse reactions
CNS: drowsiness, depression, dizziness, nervousness, nightmares
CV: hypotension (especially with epidural use), palpitations, bradycardia
GI: nausea, vomiting, constipation, dry mouth
GU: urinary retention, nocturia, erectile dysfunction
Metabolic: sodium retention
Skin: rash, sweating, pruritus, dermatitis
Other: weight gain, withdrawal phenomenon
Interactions
Drug-drug. Amphetamines, beta-adrenergic blockers, MAO inhibitors, prazosin, tricyclic antidepressants: decreased antihypertensive effect Beta-adrenergic blockers: increased withdrawal phenomenon
CNS depressants (including antihistamines, opioids, sedative-hypnotics): additive sedation
Epidurally administered local anesthetics: prolonged clonidine effects
Levodopa: decreased levodopa efficacy
Myocardial depressants (including beta-adrenergic blockers): additive bradycardia
Other antihypertensives, nitrates: additive hypotension
Verapamil: increased risk of adverse cardiovascular reactions
Drug-herbs. Capsicum: reduced anti-hypertensive effect
Drug-behaviors. Alcohol use: increased sedation
Patient monitoring
• Monitor patient for signs and symptoms of adverse cardiovascular reactions.
• Frequently assess vital signs, especially blood pressure and pulse.
• Monitor patient for drug tolerance and efficacy.
Patient teaching
• Instruct patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness caused by sudden blood pressure decrease.
See Caution patient not to stop taking drug abruptly.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, herbs, and behaviors mentioned above.