Penbutolol

INTRODUCTION

Indications

Management of hypertension.

Action

Blocks stimulation of beta₁ (myocardial) and beta₂ (pulmonary, vascular, and uterine)–adrenergic receptor sites. Also has intrinsic sympathomimetic activity (ISA), which may produce less bradycardia. Therapeutic Effects: Decreased heart rate and blood pressure.

Adverse Reactions/Side Effects

CNS: fatigue, weakness, anxiety, depression, dizziness, drowsiness, insomnia, memory loss, mental status changes, nervousness, nightmares. EENT: blurred vision, dry eyes, nasal stuffiness. Resp: bronchospasm, wheezing. CV: ARRHYTHMIAS, BRADYCARDIA, CHF, PULMONARY EDEMA, orthostatic hypotension, peripheral vasoconstriction. GI: constipation, diarrhea, nausea. GU: erectile dysfunction, decreased libido. Derm: itching, rashes. Endo: hyperglycemia, hypoglycemia. MS: arthralgia, back pain, muscle cramps. Neuro: paresthesia. Misc: drug-induced lupus syndrome.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

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

• Assess routinely for signs of CHF and pulmonary edema, including dyspnea, rales/crackles, weight gain, peripheral edema, and jugular venous distention. Report these signs to the physician immediately.

• Assess blood pressure (BP) periodically and compare to normal values (See Appendix F) to help document antihypertensive effects.

• Assess BP when patient assumes a more upright position (lying to standing, sitting to standing, lying to sitting). Document orthostatic hypotension and contact physician when systolic BP falls >20 mm Hg, or diastolic BP falls >10 mm Hg.

• Assess symptoms of bronchospasm (wheezing, coughing, tightness in chest). Perform pulmonary function tests to quantify suspected changes in ventilation and respiration (See Appendices I, J, K). Repeated or prolonged bronchoconstriction may require a change in dose or medication (e.g., switch to a more cardioselective beta blocker).

• Monitor signs of peripheral vasoconstriction, such as extreme coldness in the hands and feet, cyanosis, and muscle cramping. Notify physician of severe or prolonged signs of vasoconstriction.

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

• Assess signs of paresthesia (numbness, tingling), and perform objective tests, including electroneuromyography and sensory testing to document any drug-related neuropathic changes.

• Monitor mood and personality changes, including depression, anxiety, memory loss, or other changes in behavior. Notify physician if these changes become problematic.

• 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.

• Monitor excessive fatigue or weakness. Beta blockers often cause some degree of fatigue and weakness, but any sudden ...