Clonidine

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 ).

"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 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.

Most common dose-related reactions: "dry mouth, occurring in about 40 of 100 patients; drowsiness, about 33 in 100; dizziness, about 16 in 100; constipation and sedation, each about 10 in 100." Other reported effects span cardiovascular (bradycardia, arrhythmias), CNS (depression, hallucinations), dermatologic (rash, urticaria), and genitourinary categories (including erectile dysfunction).