Clonidine

Brand names: CLONIDINE HYDROCHLORIDE, Catapres, Clonidine HYDROCHLORIDE, Clonidine Hydrochloride, Clonidine hydrochloride, Clonidine hydrochloride extended-release, Clorpres, Kapvay, Nexiclon, Nexiclon XR, clonidine hydrochloride, Clonidine transdermal system, Clonidine

Boxed warning

The 500 mcg/mL strength product should be diluted prior to use in an appropriate solution.

Warnings

No boxed warning. Contraindicated in patients with "known hypersensitivity to clonidine." Most critical warning concerns abrupt discontinuation: "Sudden cessation of clonidine treatment has, in some cases, resulted in symptoms such as nervousness, agitation, headache, and tremor accompanied or followed by a rapid rise in blood pressure," so the dose should be "reduced gradually over 2 to 4 days." The label also warns the drug "may worsen sinus node dysfunction and atrioventricular (AV) block, especially in patients taking other sympatholytic drugs."

Contraindications

CONTRAINDICATIONS Clonidine transdermal system should not be used in patients with known hypersensitivity to clonidine or to any other component of the system.

Overdose

OVERDOSAGE Hypertension may develop early and may be followed by hypotension, bradycardia, respiratory depression, hypothermia, drowsiness, decreased or absent reflexes, weakness, irritability and miosis. The frequency of CNS depression may be higher in children than adults. Large overdoses may result in reversible cardiac conduction defects or dysrhythmias, apnea, coma and seizures. Signs and symptoms of overdose generally occur within 30 minutes to two hours after exposure. As little as 0.1 mg of clonidine has produced signs of toxicity in children. If symptoms of poisoning occur following dermal exposure, remove all clonidine transdermal systems. After their removal, the plasma clonidine levels will persist for about 8 hours, then decline slowly over a period of several days. Rare cases of clonidine transdermal system poisoning due to accidental or deliberate mouthing or ingestion of the patch have been reported, many of them involving children. There is no specific antidote for clonidine overdosage. Ipecac syrup-induced vomiting and gastric lavage would not be expected to remove significant amounts of clonidine following dermal exposure. If the patch is ingested, whole bowel irrigation may be considered and the administration of activated charcoal and/or cathartic may be beneficial. Supportive care may include atropine sulfate for bradycardia, intravenous fluids and/or vasopressor agents for hypotension and vasodilators for hypertension. Naloxone may be a useful adjunct for the management of clonidine-induced respiratory depression, hypotension and/or coma; blood pressure should be monitored since the administration of naloxone has occasionally resulted in paradoxical hypertension. Dialysis is not likely to significantly enhance the elimination of clonidine. The largest overdose reported to date, involved a 28-year old male who ingested 100 mg of clonidine hydrochloride powder. This patient developed hypertension followed by hypotension, bradycardia, apnea, hallucinations, semicoma, and premature ventricular contractions. The patient fully recovered after intensive treatment. Plasma clonidine levels were 60 ng/mL after 1 hour, 190 ng/mL after 1.5 hours, 370 ng/mL after 2 hours, and 120 ng/mL after 5.5 and 6.5 hours. In mice and rats, the oral LD 50 of clonidine is 206 and 465 mg/kg, respectively.

Drug interactions

Drug Interactions Clonidine may potentiate the CNS-depressive effects of alcohol, barbiturates or other sedating drugs. If a patient receiving clonidine is also taking tricyclic antidepressants, the hypotensive effect of clonidine may be reduced, necessitating an increase in the clonidine dose. If a patient receiving clonidine is also taking neuroleptics, orthostatic regulation disturbances (e.g., orthostatic hypotension, dizziness, fatigue) may be induced or exacerbated. Monitor heart rate in patients receiving clonidine concomitantly with agents known to affect sinus node function or AV nodal conduction, e.g., digitalis, calcium channel blockers, and beta-blockers. Sinus bradycardia resulting in hospitalization and pacemaker insertion has been reported in association with the use of clonidine concomitantly with diltiazem or verapamil. Amitriptyline in combination with clonidine enhances the manifestation of corneal lesions in rats (see Toxicology ).

Uses

"Clonidine hydrochloride tablets are indicated in the treatment of hypertension" and "may be employed alone or concomitantly with other antihypertensive agents" to lower blood pressure.

Dosage forms & strengths

Tablet Tablet, Extended Release PATCH POWDER TABLET, EXTENDED RELEASE PATCH, EXTENDED RELEASE INJECTION, SOLUTION

CLONIDINE 0.17 mg CLONIDINE 0.26 mg CLONIDINE HYDROCHLORIDE .1 mg CLONIDINE HYDROCHLORIDE .2 mg CLONIDINE HYDROCHLORIDE .3 mg CLONIDINE HYDROCHLORIDE 0.1 mg CHLORTHALIDONE 15 mg CLONIDINE HYDROCHLORIDE 0.100 mg CLONIDINE HYDROCHLORIDE 0.2 mg CLONIDINE HYDROCHLORIDE 0.200 mg CLONIDINE HYDROCHLORIDE 0.3 mg CLONIDINE HYDROCHLORIDE 0.300 mg CLONIDINE HYDROCHLORIDE 25 mg Clonidine Hydrochloride 0.1 mg Clonidine Hydrochloride 0.2 mg Clonidine Hydrochloride 0.3 mg clonidine hydrochloride 0.1 mg clonidine hydrochloride 0.100 mg clonidine hydrochloride 0.2 mg clonidine hydrochloride 0.200 mg clonidine hydrochloride 0.3 mg clonidine hydrochloride 0.300 mg CLONIDINE .1 mg/d CLONIDINE .2 mg/d CLONIDINE .3 mg/d CLONIDINE 1 kg/kg CLONIDINE HYDROCHLORIDE .1 mg/1 CLONIDINE .3 mg/24h CLONIDINE .17 mg/1 CLONIDINE 25 kg/25kg CLONIDINE .2 mg/24h CLONIDINE 1 kg/1 CLONIDINE HYDROCHLORIDE 500 ug/mL CLONIDINE HYDROCHLORIDE 100 ug/mL CLONIDINE .1 mg/24h

DOSAGE AND ADMINISTRATION Apply clonidine transdermal system once every 7 days to a hairless area of intact skin on the upper outer arm or chest. Each new application of clonidine transdermal system should be on a different skin site from the previous location. If the system loosens during 7-day wearing, the adhesive cover should be applied directly over the system to ensure good adhesion. There have been rare reports of the need for patch changes prior to 7 days to maintain blood pressure control. To initiate therapy, clonidine transdermal system dosage should be titrated according to individual therapeutic requirements, starting with clonidine transdermal system, 0.1 mg per day for one week. If after one or two weeks the desired reduction in blood pressure is not achieved, increase the dosage by adding another clonidine transdermal system, 0.1 mg per day for one week or changing to a larger system. An increase in dosage above two clonidine transdermal systems, 0.3 mg per day for one week is usually not associated with additional efficacy. When substituting clonidine transdermal system for oral clonidine or for other antihypertensive drugs, physicians should be aware that the antihypertensive effect of clonidine transdermal system may not commence until 2 to 3 days after initial application. Therefore, gradual reduction of prior drug dosage is advised. Some or all previous antihypertensive treatment may have to be continued, particularly in patients with more severe forms of hypertension. Renal Impairment Patients with renal impairment may benefit from a lower initial dose. Patients should be carefully monitored. Since only a minimal amount of clonidine is removed during routine hemodialysis, there is no need to give supplemental clonidine following dialysis.