CLONIDINE patch warnings and precautions

# Warnings

### Withdrawal
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, tremor, 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 Clonidine Transdermal System, 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 Clonidine Transdermal 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is to be discontinued in patients receiving a beta-blocker and clonidine concurrently, the beta-blocker should be withdrawn several days before the gradual discontinuation of Clonidine Transdermal System.

# Precautions

### General
In patients who have developed localized contact sensitization to Clonidine Transdermal System continuation of Clonidine Transdermal 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 Clonidine Transdermal System, substitution of oral clonidine hydrochloride may also elicit an allergic reaction (including generalized rash, urticaria, or angioedema).
The sympatholytic action of clonidine may worsen sinus node dysfunction and atrioventricular (AV) block, especially in patients taking other sympatholytic drugs. There are post-marketing reports of patients with conduction abnormalities and/or taking other sympatholytic drugs who developed severe bradycardia requiring IV atropine, IV isoproterenol and temporary cardiac pacing while taking clonidine.
In hypertension caused by pheochromocytoma, no therapeutic effect of Clonidine Transdermal System can be expected.
In rare instances, loss of blood pressure control has been reported in patients using Clonidine Transdermal System according to the instructions for use.

### Perioperative Use
Clonidine Transdermal 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 Clonidine Transdermal 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 Clonidine Transdermal 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.