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Related to clonidine: clonazepam, Clonidine hydrochloride


a centrally acting antihypertensive agent, administered orally as the hydrochloride salt; also used to treat migraine, dysmenorrhea, opioid withdrawal, vasomotor symptoms of menopause, and cancer-associated pain.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.



clonidine hydrochloride

Apo-Clonidine (CA) Catapres, Dixarit (CA) Dom-Clonidine (CA), Duraclon (UK), Novo-Clonidine (CA), Nu-Clonidine (CA)

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.


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.


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


• Hypersensitivity to drug

• Hypersensitivity to components of adhesive layer (transdermal form)

• Infection at epidural injection site, bleeding problems (epidural use)

• Concurrent anticoagulant therapy


Use cautiously in:

• renal insufficiency, serious cardiac or cerebrovascular disease

• elderly patients

• pregnant or breastfeeding patients.


• 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


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.

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.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


(klŏn′ĭ-dēn′, klō′nĭ-)
A synthetic drug, C9H9Cl2N3 that is used primarily in the treatment of hypertension, the prevention of migraine headaches, and the management of opioid withdrawal.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


An alpha2 adrenoreceptor stimulator (AGONIST) that is effective in lowering blood pressure and controlling some cases of MIGRAINE and postmenopausal flushing. Stopping treatment may produce a dangerous rise in blood pressure. Brand names are Dixarit and Catapres.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
Group "A" patient received tablet of Gabapentin 900 mg and Group "B" patient received tablet of Clonidine 200 microgram
A retrospective study of clonidine-overdose patients characterized the clonidine overdose syndrome as marked by sedation, hypotension, bradycardia, and excessive pupillary constriction (Clin Toxicol [Phila].
[6-8] We had used clonidine and dexmedetomidine in a safe allowable doses to get maximum benefit.
[3] Clonidine, an [alpha]-2 adrenoceptor agonist, decreases norepinephrine release from nerve terminals [4] resulting to a dose-dependent decrease in the concentration of catecholamines in the blood after an oral administration.
Clonidine, an imidazoline derivative, is a centrally acting hypotensive agent but its use is being explored in a number of other indications such as anesthesia and the management of opiate withdrawal (Figure 1) (1).
Roquennedy Souza Cruz et al showed that 200 g Oral clonidine decreases IOP in the preoperative and postoperative phase more than 100 g.13
The incidence of the primary outcome, death or nonfatal myocardial infarction at 30 days, did not differ significantly with either aspirin versus placebo or between placebo and clonidine. Aspirin did not improve outcomes whether or not patients received daily doses of aspirin before surgery.
(2-9) In addition, clonidine and diltiazem also reduce blood pressure.
Clonidine can be combined with other drugs used for treating fear and anxiety, including selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (Prozac, Reconcile), and tricyclic antidepressants (TCAs), such as clomipramine (Clomicalm).
It considers clonidine and nortriptyline second-line therapies.
Clonidine was actually synthesized in the early 1960s for use as a nasal decongestant, and then by chance, researchers discovered it decreased blood pressure and heart rate and produced sedation at very low doses.