Norepinephrine

INTRODUCTION

Indications

Produces vasoconstriction and myocardial stimulation, which may be required after adequate fluid replacement in the treatment of severe hypotension and shock.

Action

Stimulates alpha-adrenergic receptors located mainly in blood vessels, causing constriction of both capacitance and resistance vessels. Also has minor betaadrenergic activity (myocardial stimulation). Therapeutic Effects: Increased blood pressure. Increased cardiac output.

Adverse Reactions/Side Effects

CNS: anxiety, dizziness, headache, insomnia, restlessness, tremor, weakness. Resp: dyspnea. CV: arrhythmias, bradycardia, chest pain, hypertension. GU: decreased urine output, renal failure. Endo: hyperglycemia. F and E: metabolic acidosis. Local: phlebitis at IV site. Misc: fever.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess blood pressure periodically and compare to normal values (See Appendix F). Report a sustained increase in blood pressure (hypertension) to the physician.

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report a slow heart rate or symptoms of other arrhythmias, including chest pain, palpitations, shortness of breath, fainting, and fatigue/weakness.

• Monitor signs of renal failure, including decreased urine output, increased blood pressure, muscle cramps/twitching, edema/weight gain from fluid retention, yellowish brown skin, and confusion that progresses to seizures and coma. Report these signs to the physician immediately.

• Monitor signs of metabolic acidosis, including headache, lethargy, stupor, seizures, vision disturbances, increased respiration, cardiac arrhythmias, weakness, and GI symptoms (nausea, vomiting, abdominal pain). Notify physician or nursing staff immediately if these signs occur.

• Be alert for signs of hyperglycemia, including confusion, drowsiness, flushed/dry skin, fruit-like breath odor, rapid/deep breathing, polyuria, loss of appetite, and unusual thirst. Patients with diabetes mellitus should check blood glucose levels frequently.

• Monitor and report signs of CNS toxicity, including anxiety, restlessness, insomnia, or tremor. Sustained or severe CNS signs may indicate overdose or excessive use of this drug.

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

• Assess IV site during and after IV administration, and report signs of phlebitis (local pain, swelling, inflammation).

Interventions

• Because of the risk of arrhythmias, angina pectoris, and increased BP, use caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (blood pressure, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

Patient/Client-Related Instruction

• Instruct patient and family/caregivers to report severe or prolonged fever or difficult, labored breathing.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.