The Effects of Viagra on the Body

Medically reviewed by Alan Carter, PharmD on August 26, 2015Written by Ann Pietrangelo on October 19, 2015

Viagra is a powerful drug that increases blood flow to the penis so you can get and maintain an erection. It’s effective, but can cause some side effects.

Effects of viagra

The Effects of Viagra on the Body

Viagra is a brand name for the generic drug sildenafil. It’s a phosphodiesterase type 5 (PDE-5) inhibitor. PDE-5 is an enzyme that can stop you from having an erection.

This medication is used to treat erectile dysfunction (ED). While it helps you temporarily maintain an erection so you can have sex, it does not cure ED. Also, it does not affect sexual desire. You still need mental or physical stimulation to get an erection.

5 Common Causes of Impotence »

Viagra is available only with a doctor’s prescription.

Circulatory System

Beginning with arousal signals from your brain, it takes a finely choreographed series of events to produce an erection. And it all hinges on good blood flow to the penis.

Within the penis are two chambers called the corpora cavernosa. Nitric oxide (NO) is released in the chambers during sexual stimulation. NO activates an enzyme called guanylate cyclase. That increases levels of cyclic guanosine monophosphate (cGMP), which causes muscles to relax.

The chambers also contain a network of blood vessels. When those blood vessels relax and widen, blood rushes in. The resulting pressure is what causes an erection.

PDE-5 can dampen the effect of cGMP. Viagra works by inhibiting PDE-5.

Viagra is rapidly absorbed into the bloodstream. Maximum concentrations are reached within an hour.

One of the more common side effects is flushing, or redness.

This medication can cause a decrease in blood pressure, particularly one to two hours after taking it. If you already have low blood pressure, discuss the pros and cons of Viagra with your doctor.

For most people, sexual activity is good for cardiovascular health. However, if you have cardiovascular disease, you should ask your doctor if it’s safe for you to take Viagra. You should also avoid Viagra if your doctor advised you not to have sex.

You should not take Viagra if you have had a stroke, heart attack, or have unstable angina.

Certain drug interactions can harm your heart. Avoid taking PDE-5 inhibitors if you also use long lasting alpha blockers or take medications that contain nitrates.

Reproductive System

Viagra can be quite effective, but it’s no magic pill. It does nothing for your libido. You still need some kind of stimulation to get an erection.

The effects of Viagra usually last about four hours, though it may last longer for some men. A rare, but serious side effect, is priapism. That’s when you get an erection that lasts for a long period of time. It can become quite painful. If you have an erection that lasts for more than four hours, seek immediate medical attention.

You should also be wary of PDE-5 inhibitors if you have an anatomical abnormality of the penis. If you have Peyronie’s disease, your doctor may advise against taking Viagra.

Viagra is a temporary fix and does not cure ED. It offers no protection from sexually transmitted diseases.

Central Nervous System

Viagra helps to improve blood flow to the penis, but your brain is still your most valuable sex organ. Viagra won’t work if you’re not in the mood.

Some potential side effects of Viagra are headache and runny or blocked nose. Some men feel lightheaded or dizzy. Rarely, Viagra can cause fainting. Some men taking PDE-5 inhibitors report back or muscle pain.

It’s not common, but some men experience ringing in the ears, hearing loss, or vision loss after taking PDE-5 inhibitors. Avoid PDE-5 inhibitors if you have a history of an eye condition called non-arteritic anterior ischaemic optic neuropathy.

If you have hearing or vision loss while taking Viagra, seek immediate medical help.

Digestive and Excretory System

One fairly common side effect of Viagra is indigestion or heartburn. PDE-5 inhibitors can sometimes cause nausea or vomiting.

Viagra is dispensed in a film-coated tablet. You can take Viagra with or without food, and it’s best to take it about one hour before you plan to have sex.

About 80 percent of Viagra leaves your body in your feces. The rest is washed out with your urine.

CMS Id: 87575