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clonidine
Catapres-TTS

clonidine hydrochloride
Catapres, Dixarit†‡

Pregnancy Risk Category C

How supplied
clonidine

Transdermal:
TTS-1 (releases 0.1 mg/24 hours), TTS-2 (releases 0.2 mg/24 hours), TTS-3 (releases 0.3 mg/24 hours)
clonidine hydrochloride

Tablets:
0.025 mg†‡, 0.1 mg, 0.2 mg, 0.3 mg

Action
Unknown. Thought to stimulate alpha2-adrenergic receptors centrally and inhibit the central vasomotor centers, thereby decreasing sympathetic outflow to the heart, kidneys, and peripheral vasculature, resulting in decreased peripheral vascular resistance, systolic and diastolic blood pressure, and heart rate.

Indications & dosage
Essential and renal hypertension
--
Adults:
initially, 0.1 mg P.O. b.i.d.; then increased by 0.1 to 0.2 mg daily on a weekly basis. Usual range is 0.2 to 0.6 mg daily in divided doses; infrequently, dosages as high as 2.4 mg daily are used.
Or, a transdermal patch is applied to a nonhairy area of intact skin on upper arm or torso once q 7 days, starting with 0.1-mg system and adjusted with another 0.1-mg system or larger system.
Children:
50 to 400 mcg P.O. b.i.d.

Adverse reactions
CNS:
drowsiness, dizziness, fatigue, sedation, weakness, malaise, agitation, depression.
CV:
orthostatic hypotension, bradycardia, severe rebound hypertension.
GI:
constipation, dry mouth, nausea, vomiting, anorexia.
GU:
urine retention, impotence, loss of libido.
Metabolic:
weight gain.
Skin:
pruritus, dermatitis with transdermal patch, rash.

Interactions
Drug-drug.
CNS depressants: enhanced CNS depression. Use together cautiously.
Diuretics, other antihypertensives:
increased hypotensive effect. Monitor closely.
Levodopa:
may reduce effectiveness of levodopa. Monitor patient.
MAO inhibitors, prazosin, tricyclic antidepressants:
may decrease antihypertensive effect. Use together cautiously.
Propranolol, other beta blockers:
paradoxical hypertensive response. Monitor carefully.
Verapamil:
may cause AV block and severe hypotension. Monitor carefully.
Drug-herb.
Capsicum: may reduce antihypertensive effectiveness. Avoid concomitant use.

Effects on diagnostic tests
Clonidine may decrease urinary excretion of vanillylmandelic acid and catecholamines, and may cause a weakly positive Coombs' test.

Contraindications
Contraindicated in patients with hypersensitivity to drug. Transdermal form is contraindicated in patients with hypersensitivity to any component of the adhesive layer of transdermal system.

Nursing considerations

Patient teaching

*Liquid contains alcohol. **May contain tartrazine.  †Canada  ‡Australia  §U.K.  OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING

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