Sildenafil

INTRODUCTION

Indications

Viagra: Erectile dysfunction. Revatio: Pulmonary hypertension.

Action

Viagra: Enhances effects of nitric oxide released during sexual stimulation. Nitric oxide activates guanylate cyclase, which produces increased levels of cyclic guanosine monophosphate (cGMP). cGMP produces smooth muscle relaxation of the corpus cavernosum, which promotes increased blood flow and subsequent erection. Sildenafil inhibits the enzyme phosphodiesterase type 5 (PDE5); PDE5 inactivates cGMP. Revatio: Produces vasodilation of the pulmonary vascular bed. Therapeutic Effects: Viagra: Enhanced blood flow to the corpus cavernosum and erection sufficient to allow sexual intercourse. Requires sexual stimulation. Revatio: Improved exercise tolerance.

Adverse Reactions/Side Effects

CNS: headache, dizziness, insomnia. EENT: HEARING LOSS, VISION LOSS, epistaxis, nasal congestion. CV: MI, SUDDEN DEATH, CARDIOVASCULAR COLLAPSE. GI: dyspepsia, diarrhea. GU: priapism, urinary tract infection.

Derm: flushing, rash. MS: myalgia. Neuro: paresthesias.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor cardiac symptoms at rest and during exercise, and be alert for signs of severe cardiac insufficiency due to myocardial infarction (MI) or cardiovascular collapse. Seek immediate medical assistance if symptoms of cardiac arrest develop, including sudden chest pain, pain radiating into the arm or jaw, shortness of breath, dizziness, sweating, anxiety, and nausea.

• Be alert for sudden loss of vision or hearing, and seek emergency care for any changes in vision or hearing.

• For patients with pulmonary hypertension, assess exercise tolerance and other symptoms (shortness of breath, fatigue, dizziness, chest pain, peripheral edema) to help document whether drug therapy is effective in reducing these symptoms.

• Assess any muscle pain 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). Perform objective tests, including electroneuromyography and sensory testing to document any drug-related neuropathic changes.

• Assess dizziness 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.

Interventions

• Because of the risk of MI and cardiovascular collapse, use extreme 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

• Advise patient and family or caregivers about the signs of cardiac arrest (see above under Examination and Evaluation), and to seek immediate medical assistance if these signs develop.

• Instruct patient to notify health care professional promptly if erection lasts longer than 4 hr or if they experience ...