Side effects

Most men who take oral erectile dysfunction medications aren't bothered by side effects. When side effects do occur, they can include:

• Flushing
• Headache
• Indigestion
• Visual changes, such as blue tinge to vision, sensitivity to light or blurred vision
• Stuffy or runny nose
• Back pain

Rarely, more-serious side effects can occur, including:

• Hearing loss or vision loss. Some men have had sudden loss of hearing or loss of vision after taking one of these medications. However, it isn't clear whether vision or hearing loss was directly caused by taking the medication or by a preexisting condition. If you're taking an oral erectile dysfunction medication and have sudden loss of hearing or vision, seek prompt medical attention.
• An erection that doesn't go away on its own. Called priapism, this rare condition can be painful and requires medical treatment to avoid damage to your penis. If you have an erection that lasts more than four hours, seek immediate medical attention.