Not recommended for continuous daily use. Discontinue use in case of visual defects; sudden decrease or loss of hearing. Perform medical history & physical exam, & determine potential underlying causes before treatment. Consider CV status of patients prior to initiating any treatment. Patients who have undergone pelvic surgery or radical non-nerve-sparing prostatectomy. Serious CV events including MI, sudden cardiac death, unstable angina pectoris, ventricular arrhythmia, stroke, transient ischemic attacks, chest pain, palpitations & tachycardia; HTN & hypotension (including postural hypotension); visual defects & cases of NAION; sudden decrease or loss of hearing, which may be accompanied by tinnitus. Seek immediate medical assistance if patients experience erections lasting ≥4 hr. Caution in patients w/ anatomical penis deformation (eg, angulation, cavernosal fibrosis or Peyronie's disease), pre-disposing conditions to priapism (eg, sickle cell anaemia, multiple myeloma or leukaemia). Concomitant use w/ antihypertensives; α1-blockers; potent CYP3A4 inhibitors (ritonavir, saquinavir, ketoconazole, traconazole, & erythromycin); other PDE5 inhibitors or treatments for erectile dysfunction. Not recommended in combination w/ guanylate cyclase stimulators, doxazosin. Not to be taken in patients w/ rare hereditary problems of galactose intolerance, total lactose deficiency or glucose-galactose malabsorption. May affect ability to drive & use machines. Not recommended in patients w/ severe renal impairment. Severe hepatic impairment (Child-Pugh Class C). Not indicated for use by women. Avoid use during pregnancy. Not to be used during breastfeeding. Not to be used in childn <18 yr.