Doxazosin

INTRODUCTION

Indications

Hypertension (alone or with other agents). Symptomatic benign prostatic hyperplasia (BPH).

Action

Dilates both arteries and veins by blocking postsynaptic alpha₁-adrenergic receptors. Therapeutic Effects: Lowering of blood pressure.

Adverse Reactions/Side Effects

CNS: dizziness, headache, depression, drowsiness, fatigue, nervousness, weakness. EENT: abnormal vision, blurred vision, conjunctivitis, epistaxis. Resp: dyspnea. CV: first-dose orthostatic hypotension, arrhythmias, chest pain, edema, palpitations. GI: abdominal discomfort, constipation, diarrhea, dry mouth, flatulence, nausea, vomiting. GU: decreased libido, sexual dysfunction. Derm: flushing, rash, urticaria. MS: arthralgia, arthritis, gout, myalgia.

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, be alert for a fall in blood pressure (BP) and related symptoms (dizziness, syncope) that occur when the patient changes position (orthostatic hypotension), especially after the initial doses. Document orthostatic hypotension and contact physician when systolic BP falls >20 mm Hg or diastolic BP falls >10 mm Hg.

• If treating BPH, monitor signs such as difficulty starting a urine stream, painful urination, weak urine flow, feeling that the bladder is not completely empty, frequent nighttime urination, and an urge to urinate again soon after urinating. Document any change in BPH symptoms to help determine the effects of drug therapy.

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report any rhythm disturbances or symptoms of increased arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

• Assess dizziness and weakness 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 fluid retention.

• Assess any breathing problems, and report signs of difficult or labored breathing.

• Assess any back or joint pain to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.

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, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

• Avoid physical therapy interventions that ...