Clonidine HCl

(KLOE-nih-DEEN HIGH-droe-KLOR-ide)

  Action:
Stimulates central alpha-adrenergic receptors to inhibit sympathetic cardioaccelerator and vasoconstrictor centers.

  Indications:
Management of hypertension. Used in combination with opiates for epidural use for relief of cancer pain. Unlabeled use(s): Treatment of constitutional growth delay in children, diabetic diarrhea, Gilles de la Tourette syndrome, hypertensive urgencies, menopausal flushing, postherpetic neuralgia and diagnosis of pheochromocytoma; ulcerative colitis; reduction of allergen-induced inflammatory reactions in patients with extrinsic asthma; facilitation of smoking cessation; alcohol withdrawal; and methadone/opiate detoxification.

  Contraindications:
Hypersensitivity to clonidine or any component of adhesive layer of transdermal system.

Injection: In the presence of an injection site infection; patients on anticoagulant therapy; patients with a bleeding diathesis; administration above the C4 dermatome because there are not adequate safety data to support such use.

  Route/Dosage:

Hypertension

Adults: Initial dose:
PO 0.1 mg bid; maintenance dose: increase by increments of 0.1 to 0.2 mg/day until desired response is achieved (max 2.4 mg/day in divided doses).
SL 0.2 to 0.4 mg/day.
Transdermal 0.1 mg patch weekly initially; titrate to determine best response. Dosage > two 0.3 mg patches does not improve efficacy.

Children:
PO 5 to 25 mcg/kg/day in divided doses given q 6 hr; increase dose as necessary at 5 to 7 day intervals.

Pain Relief

Adults:
Epidural infusion 30 mcg/hr as starting dose. Dosage may be titrated up or down depending on pain relief and occurrence of adverse events. Experience with dosage rates > 40 mcg/hr is limited.

  Interactions:

Alcohol, CNS depressants: Clonidine may enhance depressant effects.

Beta-adrenergic blocking agents: May increase potential for rebound hypertension when clonidine therapy is discontinued.

Local anesthetics: Epidural clonidine may prolong the duration of pharmacologic effects of epidural local anesthetics, including sensory and motor blockade.

Narcotic analgesics: May potentiate the hypotensive effects of clonidine.

Tricyclic antidepressants: May reduce effect of clonidine.

  Lab Test Interferences:
None well documented.

  Adverse Reactions:

CV:

CHF; orthostatic symptoms; palpitations; tachycardia; bradycardia.

CNS:

drowsiness; dizziness; sedation; nightmares; insomnia; nervousness or agitation; headache; fatigue; hypotension (epidural only); confusion (epidural only).

DERM:

Rash; urticaria; erythema (with transdermal form); transient localized skin reactions; pruritus.

EENT:

Itching, burning or dry eyes; retinal degeneration; dry nasal polyps.

GI:

Dry mouth; constipation; anorexia; nausea; vomiting.

GU:

Impotence; decreased libido; nocturia; difficulty in micturition; urinary retention.

META:

Weight gain; gynecomastia; transient elevations in blood glucose or serum creatinine phosphokinase.

OTHER:

Increased sensitivity to alcohol; pallor; muscle weakness; muscle or joint pain; cramps of lower limbs; weakly positive Coombs' test.

  Precautions:

Labor and delivery: Use of epidural clonidine during labor and delivery is not indicated. Postoperative or obstetrical, post-partum or peri-operative pain. The risk of hemodynamic instability especially hypotension and bradycardia may be unacceptable in these patients.

Pregnancy: Category C.

Lactation: Excreted in breast milk.

Children: Restrict the use of clonidine to pediatric patients with severe intractable pain from malignancy that is unresponsive to epidural or spinal opiates or other more conventional analgesia techniques. Select the starting dose on a per kilogram basis (0.5 mcg/kg/hr) and cautiously adjust based on clinical response.

Elderly or debilitated patients: Reduced dosage may be required.

Cardiac effects: Clonidine frequently causes decreases in heart rate. Rarely, atroventricular block greater than first degree has been reported. Clonidine does not alter the hemodynamic response to exercise but may mask the increase in heart associated hypovolemia.

Depression: Depression is commonly seen in cancer patients and may be exacerbated by clonidine treatment.

Hypotension: Because severe hypotension may follow clonidine administration, use with caution in all patients. It is not recommended in most patients with severe cardiovascular disease or in those who are otherwise hemodynamically unstable. Balance the benefit of administration in these patients against the potential risks resulting from hypotension. Monitor vital signs frequently, especially during the first few days of epidural administration. When clonidine is infused into the upper thoracic spinal segments, more pronounced decreases in BP may be seen.

Perioperative considerations: Continue clonidine therapy to within 4 hr of surgery and resume as soon as possible thereafter.

Rebound hypertension: Discontinue therapy by reducing dose gradually over 2 to 4 days to avoid rapid increase in BP.

Respiratory depression and sedation: Clonidine administration may result in sedation. High clonidine doses cause sedation and ventilatory abnormalities that are usually mild. Tolerance to these effects can develop with chronic administration.

Sensitization to transdermal clonidine: Generalized skin rash may develop in patients with localized reaction to patch if they are switched to oral clonidine.

  Administration/Storage:

Oral

• Administer in divided doses q 12 hr.
• Store tablets in tightly closed light-resistant container at room temperature.

Transdermal

• Each transdermal system has two parts: (1) patch containing active drug and (2) adhesive overlay. Apply patch to hairless area of intact skin on upper arm or torso as directed. Then apply adhesive overlay to ensure good adhesion of patch.
• Do not alter or trim patch.
• Change patch q 7 days.
• Alternate sites of patch application to prevent skin irritation.
• Before discarding old patch, fold adhesive edges together.

Epidural

• The recommended starting dose for continuous epidural infusion is 30 mcg/hr. May be titrated up or down depending on pain relief and occurrence of adverse events. Experience with dosage rates > 40 mcg/hr is limited.
• Must not be used with a preservative.
• Store at controlled room temperature 15°-30°C (50°-86°F). Discard any unused portion.

  Assessment/Interventions:

• Obtain patient history, including drug history and any known allergies.
• Assess BP and apical pulse before administering drug. If systolic BP is < 90 mm Hg or pulse is < 60 bpm, withhold drug and notify health care provider.
• Weigh patient daily and record weight.
• Note any rash or skin irritation when removing patch.
• Observe for fluid retention and weight gain.
• In diabetic patients, monitor blood glucose levels.
• Monitor BP and pulse during initial therapy.
• If drug is being given to patients who have undergone prior beta-blocker therapy, be alert for signs of rebound hypertensive crisis (eg, agitation, headache, tachycardia, sweating, flushing).

Epidural

• Implantable epidural catheters are associated with a risk of catheter-related infections. Evaluation of fever in a patient receiving epidural clonidine should include the possibility of a catheter-related infection such as meningitis or epidural abscess.
• Sudden cessation of clonidine treatment, regardless of the route of administration, has, in some cases, resulted in symptoms of nervousness, agitation, headache and tremor, accompanied or followed by a rapid rise in BP. Reactions appear to be greater after administration of higher doses with concomitant beta-blocker treatment. Special caution is advised in these situations.
• Rare instances of hypertensive encephalopathy, cerebrovascular accidents and death have been reported after abrupt clonidine withdrawal. Patients with a history of hypertension or other underlying cardiovascular conditions may be at particular risk of the consequences of abrupt discontinuation of clonidine.
• When discontinuing therapy with epidural clonidine, gradually reduce the dose over 2 to 4 days to avoid withdrawal symptoms. If therapy is to be discontinued in patients receiving a beta-blocker and clonidine concurrently, discontinue the beta-blocker several days before the gradual discontinuation of epidural clonidine.
• Caused by the possibility of severe hypotension, monitor signs frequently especially during the first few days of epidural clonidine therapy. When clonidine is infused into the upper thoracic spinal segments, more pronounced decreases in BP may be seen.
• Monitor for signs and symptoms of depression, especially in patients with a known history of affective disorders.
• May produce drowsiness.

  Patient/Family Education:

• Instruct diabetic patients to monitor blood glucose levels.
• Tell patient to adhere to any fluid or dietary restrictions given by health care provider.
• Caution patient not to stop taking medication abruptly.
• Advise patient on long-term therapy to have regular eye examinations to monitor for retinal degeneration.
• Inform patient that fatigue and constipation may be experienced for a few weeks after drug therapy is begun.
• Instruct patient to report these symptoms to health care provider: respiratory distress, constricted pupils, tremors, impotence or decreased libido.
• Advise patient to take sips of water frequently, suck on ice chips or sugarless hard candy or chew sugarless gum if dry mouth occurs.
• Caution patient to avoid sudden position changes to prevent orthostatic hypotension. Suggest to patient to dangle legs at bedside before standing.
• Advise patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness.
• Instruct patient not to take otc medications without consulting health care provider.

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