Clonidine

INTRODUCTION

Indications

PO, Transdermal: Management of mild-to-moderate hypertension. Epidural: Management of cancer pain unresponsive to opioids alone. Unlabeled Use: Management of opioid withdrawal.

Action

Stimulates alpha-adrenergic receptors in the CNS; which results in decreased sympathetic outflow inhibiting cardioacceleration and vasoconstriction centers. Prevents pain signal transmission to the CNS by stimulating alpha-adrenergic receptors in the spinal cord. Therapeutic Effects: Decreased blood pressure. Decreased pain.

Adverse Reactions/Side Effects

CNS: drowsiness, depression, dizziness, nervousness, nightmares. CV: bradycardia, hypotension (increased with epidural), palpitations. GI: dry mouth, constipation, nausea, vomiting. GU: erectile dysfunction. Derm: rash, sweating. F and E: sodium retention. Metab: weight gain. Misc: withdrawal phenomenon.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess blood pressure periodically and compare to normal values (See Appendix F). Document whether drug therapy is successful in controlling hypertension. Also report low blood pressure (BP), especially if patient experiences dizziness or syncope.

• If used to treat cancer pain, use appropriate pain scales (visual analogue scales, others) to document whether this drug is successful in helping manage the patient's pain.

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report an unusually slow heart rate (HR) (bradycardia) or signs of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

• Assess dizziness and drowsiness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

• Be alert for signs of depression, nervousness, or other changes in mood and behavior. Notify physician if these changes become problematic.

• Assess peripheral edema using girth measurements, volume displacement, and measurement of pitting edema (See Appendix N). Report increased swelling in feet and ankles or a sudden increase in body weight due to sodium and water retention.

• Be alert for a rapid increase in BP and HR if clonidine is suddenly discontinued (withdrawal phenomenon). Report these increases to the physician immediately.

Interventions

• Because of the risk of arrhythmias and abnormal BP responses, use caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (BP, HR, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

• Avoid physical therapy interventions that cause systemic vasodilation (large whirlpool, Hubbard tank). Additive effects of this drug and the intervention may cause a dangerous fall in BP.

• If treating cancer pain, implement appropriate interventions (physical agents, manual techniques, therapeutic exercise) as tolerated to manage pain and reduce the need for drug therapy. Help patient also explore ...