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Patients should be instructed not to discontinue therapy without consulting their physician. Sudden cessation of clonidine treatment has, in some cases, resulted in symptoms such as nervousness, agitation, headache, and confusion accompanied or followed by a rapid rise in blood pressure and elevated catecholamine concentrations in the plasma. The likelihood of such reactions to discontinuation of clonidine therapy appears to be greater after administration of higher doses or continuation of concomitant beta-blocker treatment and special caution is therefore advised in these situations. Rare instances of hypertensive encephalopathy, cerebrovascular accidents and death have been reported after clonidine withdrawal. When discontinuing therapy with Catapres, the physician should reduce the dose gradually over 2 to 4 days to avoid withdrawal symptomatology.
An excessive rise in blood pressure following discontinuation of Catapres-TTS (clonidine) transdermal therapeutic system therapy can be reversed by administration of oral clonidine hydrochloride or by intravenous phentolamine. If therapy is to be discontinued in patients receiving a beta blocker and clonidine concurrently, the beta-blocker should be withdrawn several days before the gradual discontinuation of Catapres-TTS (clonidine) transdermal therapeutic system.
In patients who have developed localized contact sensitization to Catapres-TTS (clonidine) transdermal therapeutic system continuation of Catapres-TTS (clonidine) transdermal therapeutic system or substitution of oral clonidine hydrochloride therapy may be associated with development of a generalized skin rash.
In patients who develop an allergic reaction to Catapres-TTS (clonidine) transdermal therapeutic system, substitution of oral clonidine hydrochloride may also elicit an allergic reaction (including generalized rash, urticaria, or angioedema).
Catapres-TTS (clonidine) transdermal therapeutic system should be used with caution in patients with severe coronary insufficiency, conduction disturbances, recent myocardial infarction, cerebrovascular disease, or chronic renal failure.
In rare instances, loss of blood pressure control has been reported in patients using Catapres-TTS (clonidine) transdermal therapeutic system according to the instructions for use.
Catapres-TTS (clonidine) transdermal therapeutic system therapy should not be interrupted during the surgical period. Blood pressure should be carefully monitored during surgery and additional measures to control blood pressure should be available if required. Physicians considering starting Catapres-TTS (clonidine) transdermal therapeutic system therapy during the perioperative period must be aware that therapeutic plasma clonidine levels are not achieved until 2 to 3 days after initial application of Catapres-TTS (clonidine) transdermal therapeutic system (see DOSAGE AND ADMINISTRATION).
Defibrillation or Cardioversion
The transdermal clonidine systems should be removed before attempting defibrillation or cardioversion because of the potential for altered electrical conductivity which may increase the risk of arcing, a phenomenon associated with the use of defibrillators.
Skin burns have been reported at the patch site in several patients wearing an aluminized transdermal system during a magnetic resonance imaging scan (MRI). Because the Catapres-TTS (clonidine) patch contains aluminum, it is recommended to remove the system before undergoing an MRI.
Information for Patients
Patients should be cautioned against interruption of Catapres-TTS (clonidine) transdermal therapeutic system therapy without their physician's advice.
Patients who engage in potentially hazardous activities, such as operating machinery or driving, should be advised of a possible sedative effect of clonidine. They should also be informed that this sedative effect may be increased by concomitant use of alcohol, barbiturates, or other sedating drugs.
Patients who wear contact lenses should be cautioned that treatment with Catapres-TTS (clonidine) transdermal therapeutic system may cause dryness of eyes.
Patients should be instructed to consult their physicians promptly about the possible need to remove the patch if they observe moderate to severe localized erythema and/or vesicle formation at the site of application or generalized skin rash.
If a patient experiences isolated, mild localized skin irritation before completing 7 days of use, the system may be removed and replaced with a new system applied to a fresh skin site.
If the system should begin to loosen from the skin after application, the patient should be instructed to place the adhesive cover directly over the system to ensure adhesion during its 7-day use.
Used Catapres-TTS (clonidine) patches contain a substantial amount of their initial drug content which may be harmful to infants and children if accidentally applied or ingested. THEREFORE, PATIENTS SHOULD BE CAUTIONED TO KEEP BOTH USED AND UNUSED CATAPRES-TTS (clonidine) PATCHES OUT OF THE REACH OF CHILDREN. After use, CATAPRES-TTS (clonidine) should be folded in half with the adhesive sides together and discarded away from children's reach.
Instructions for use, storage and disposal of the system are provided at the end of this monograph. These instructions are also included in each box of Catapres-TTS (clonidine) transdermal therapeutic system.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Chronic dietary administration of clonidine was not carcinogenic to rats (132 weeks) or mice (78 weeks) dosed, respectively, at up to 46 to 70 times the maximum recommended daily human dose as mg/kg (9 or 6 times the MRDHD on a mg/m² basis). There was no evidence of genotoxicity in the Ames test for mutagenicity or mouse micronucleus test for clastogenicity.
Fertility of male and female rats was unaffected by clonidine doses as high as 150 mcg/kg (approximately 3 times the MRDHD). In a separate experiment, fertility of female rats appeared to be affected at dose levels of 500 to 2000 mcg/kg (10 to 40 times the oral MRDHD on a mg/kg basis; 2 to 8 times the MRDHD on a mg/m² basis).
Teratogenic Effects: Pregnancy Category C.
Reproduction studies performed in rabbits at doses up to approximately 3 times the oral maximum recommended daily human dose (MRDHD) of Catapres (clonidine hydrochloride) produced no evidence of a teratogenic or embryotoxic potential in rabbits. In rats, however, doses as low as 1/3 the oral MRDHD (1/15 the MRDHD on a mg/m² basis) of clonidine were associated with increased resorptions in a study in which dams were treated continuously from 2 months prior to mating. Increased resorptions were not associated with treatment at the same or at higher dose levels (up to 3 times the oral MRDHD) when the dams were treated on gestation days 6–15. Increases in resorption were observed at much higher dose levels (40 times the oral MRDHD on a mg/kg basis; 4 to 8 times the MRDHD on a mg/m² basis) in mice and rats treated on gestation days 1–14 (lowest dose employed in the study was 500 mcg/kg).
No adequate well-controlled studies have been conducted in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
As clonidine is excreted in human milk, caution should be exercised when Catapres-TTS (clonidine) transdermal therapeutic system is administered to a nursing woman.
Safety and effectiveness in pediatric patients have not been established in adequate and well-controlled trials (see WARNINGS, Withdrawal).
Last reviewed on RxList: 5/28/2010
This monograph has been modified to include the generic and brand name in many instances.
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