Is Viagra Safe to Take?

The prescription medication Viagra (sildenafil) for erectile dysfunction is generally safe for otherwise healthy men.

Viagra (sildenafil citrate) is a phosphodiesterase-5 (PDE5) inhibitor used to treat impotence (or erectile disfunction, ED, the inability to attain or maintain a penile erection).

How Does Viagra Work? 

• Penile erections occur when blood vessels that carry blood to the penis increase in size and deliver more blood to the penis, and blood vessels that carry blood away from the penis decrease in size and remove less blood from the penis.
• Sexual stimulation causes the production and release of nitric oxide in the penis, which causes an enzyme, guanylate cyclase, to produce cyclic guanosine monophosphate (cGMP) that is responsible for increasing and decreasing the size of blood vessels carrying blood to and from the penis and causing an erection.
• When cGMP is destroyed by the phosphodiesterase-5 enzyme, an erection ends. Viagra prevents phosphodiesterase-5 from destroying cGMP so cGMP stays around longer, which leads to a more prolonged erection. 

Common side effects of Viagra include: 

• Facial flushing
• Headaches
• Stomach pain
• Nasal congestion
• Nausea
• Dizziness
• Rash
• Urinary tract infections (UTIs)
• Diarrhea
• Inability to differentiate between the colors green and blue

Serious side effects of Viagra include: 

• Low blood pressure 
• Abnormal ejaculation
• Prolonged erections or priapism (painful erections lasting more than 4 hours)

Viagra is an FDA-approved medication considered safe for use; however, it is available by prescription only and patients should talk to their doctor before use. 

Viagra may not be safe for use by certain patients: 

• For those whom sexual activity is not advised due to cardiovascular problems
• Patients who are predisposed to priapism (painful erections lasting more than 4 hours)
• Patients with a history of non arteritic anterior ischemic optic neuropathy (NAION)
• Patients also taking alpha-blockers or anti-hypertensives
• Patients with heart disease that require nitroglycerin pills