Discontinue use if sudden visual defect, decreased or loss of hearing occur. Patients w/ preexisting CV risk factors. Increased risk of acute NAION. Patients w/ anatomical penis deformation eg, angulation, cavernosal fibrosis or Peyronie's disease, or conditions predisposing to priapism eg, sickle cell anemia, multiple myeloma or leukaemia. Assess for CV conditions prior to treatment. Not recommended in combination w/ doxazosin. Concomitant use w/ antihypertensives, α1
-blockers, other PDE5 inhibitors, CYP3A4 inhibitors. May affect ability to drive & use machines. Hepatic impairment. Not recommended for once-daily dosing in severe renal impairment. Not to be used in women. Avoid use during pregnancy. Not to be used during lactation.