Clonidine

5 WARNINGS AND PRECAUTIONS Patients should not discontinue therapy without consulting a physician. Dose reduction should be performed gradually over a 2- to 4-day period to avoid withdrawal symptomatology. Rare instances of hypertensive encephalopathy, cerebrovascular accidents and death have been reported after clonidine withdrawal. ( 5.1 ) Monitor closely and up-titrate slowly in patients with severe coronary insufficiency, conduction disturbances, recent myocardial infarction, cerebrovascular disease, or chronic renal failure. ( 5.2 ) Patients who engage in potentially hazardous activities, such as operating machinery or driving, should be advised of a possible sedative effect of clonidine. ( 5.2 ) In perioperative use, clonidine extended-release tablets may be administered up to 28 hours prior to surgery and resumed the following day. ( 5.3 ) 5.1 Withdrawal Instruct patients not to discontinue therapy without consulting their physician. Sudden cessation of clonidine treatment has resulted in symptoms such as nervousness, agitation, headache, and tremor 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 extended-release tablets, reduce the dose gradually over 2 to 4 days to avoid withdrawal symptoms. An excessive rise in blood pressure following discontinuation of clonidine extended-release tablets 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is to be discontinued in patients receiving a beta-blocker and clonidine concurrently, the beta-blocker should be withdrawn several days before the gradual discontinuation of clonidine extended-release tablets. Because children commonly have gastrointestinal illnesses that lead to vomiting, they may be particularly susceptible to hypertensive episodes resulting from abrupt inability to take medication. 5.2 General Precautions In patients who have developed localized contact sensitization to a clonidine transdermal system, substitution of oral clonidine therapy may be associated with the development of a generalized skin rash. In patients who develop an allergic reaction to a clonidine transdermal system, substitution of oral clonidine may also elicit an allergic reaction (including generalized rash, urticaria, or angioedema). Monitor carefully and up-titrate slowly in patients with severe coronary insufficiency, conduction disturbances, recent myocardial infarction, cerebrovascular disease, or chronic renal failure. Patients who engage in potentially hazardous activities, such as operating machinery or driving, should be advised of a possible sedative effect of clonidine. The sedative effect may be increased by concomitant use of alcohol, barbiturates, or other sedating drugs. 5.3 Perioperative Use Clonidine extended-release tablets may be administered up to 28 hours prior to surgery and resumed the following day. Blood pressure should be carefully monitored during surgery and additional measures to control blood pressure should be available if required.