Consider CV status prior to initiating treatment. Not to be used in men for whom sexual activity is inadvisable. Serious CV events including MI, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage & transient ischemic attack. Patients w/ increased susceptibility to vasodilators including those w/ left ventricular outflow obstruction (eg, aortic stenosis, hypertrophic obstructive cardiomyopathy) or those w/ rare syndrome of multiple system atrophy manifesting as severely impaired autonomic control of BP. Patients w/ bleeding disorders or active peptic ulceration; anatomical derformation of the penis (eg, angulation, cavernosal fibrosis or Peyronie's disease) or in conditions that may predispose them to priapism (eg, sickle cell anemia, multiple myeloma or leukemia). Resting HTN (BP >170/110), arrhythmia w/in the last 6 mth, history of cardiac failure or CAD causing unstable angina. Co-administration w/ α-blockers. May potentiate the antiaggregatory effect of Na nitroprusside. Combinations w/ other PDE5 inhibitors, or other pulmonary arterial hypertension treatments containing sildenafil (REVATIO), or other treatments for erectile dysfunction is not recommended. Patients w/ risk factors for sudden decrease or loss of hearing. May affect the ability to drive or use machinery. Not indicated in women, childn & adolescent <18 yr.