What is erectile dysfunction?

Safety is important. And it helps to know about possible side effects. 

VIAGRA can cause serious side effects. Rarely reported side effects include: 

• an erection that will not go away (priapism). If you have an erection that lasts more than 4 hours, get medical help right away. If it is not treated right away, priapism can permanently damage your penis. 
• sudden vision loss in one or both eyes. Sudden vision loss in one or both eyes can be a sign of a serious eye problem called non-arteritic anterior ischemic optic neuropathy (NAION). Stop taking VIAGRA and call your healthcare provider right away if you have sudden vision loss in one or both eyes. 
• sudden hearing decrease or hearing loss. Some people may also have ringing in their ears (tinnitus) or dizziness. If you have these symptoms, stop taking VIAGRA and contact a doctor right away.

Other important information:

VIAGRA can help a man get and keep an erection when he becomes sexually stimulated. Individual results may vary. And it’s not right for everyone. Here are some other things you should know:

Do not take VIAGRA if you:

• take any other medicines called nitrates, often prescribed for chest pain, as this may cause a sudden, unsafe drop in blood pressure.
• are allergic to sildenafil, as contained in VIAGRA and REVATIO, or any of the ingredients in VIAGRA. 

Discuss your health with your doctor to ensure that you are healthy enough for sex. If you experience chest pain, dizziness, or nausea during sex, seek immediate medical help.