What does Viagra do?

Viagra is a well-known brand of medicine used to treat erectile dysfunction (also known as “impotence”). Commonly referred to as “the little blue pill”, its name is famous around the world, however, many people still aren’t familiar with how it works and may often find themselves asking the question “What exactly does Viagra do?”. To help our patients and readers understand better, we have put together a guide explaining what Viagra does.

What is Viagra?

Viagra is a blue tablet containing the active ingredient sildenafil citrate. It is taken by men who suffer from erectile dysfunction about an hour before sex to help gain and maintain an erection.

Despite the common misconception, Viagra is not an aphrodisiac - any man taking Viagra will need to be sexually aroused in order to achieve an erection. Viagra is commonly available in three different dosages: 25mg, 50mg and 100mg, which dosage to take will vary depending on the person and sometimes may need to be increased or decreased by your doctor.

How does Viagra work?

To understand what Viagra does and how it works, you must first have an understanding of the way in which a man gains an erection. When the brain becomes aroused, it sends signals to the penis which leads to the release of a chemical called cGMP. This chemical relaxes certain muscle cells in the erectile tissue of the penis, allowing blood-flow to increase to that area.

After ejaculation, the body releases an enzyme called PDE-5, which breaks down cGMP causing the loss of the erection. Viagra, and other ED medicines, work by inhibiting the effect of PDE-5 thus increasing the blood flow to the penis and making it easy to gain and maintain an erection.

For Viagra to work properly, it should be taken an hour before sex on an empty stomach. You will need to be sexually aroused to achieve an erection and you should avoid drinking alcohol before taking Viagra, as this can limit its effectiveness.

How long does Viagra last?

Viagra lasts for around four to six hours after it has been taken. Typically, it takes effect after 30-60 minutes - provided sexual arousal has taken place and you have not eaten a fatty meal within the past few hours.

Most other ED treatments last for the same amount of time, however Cialis (tadalafil) is one exception. If you are looking for an erectile dysfunction medicine that will last for longer than six hours, then Cialis may be right for you. Taken correctly (30 minutes before sex, without alcohol) Cialis can last for up to 36 hours.

Once the effects of Viagra have worn off, it is important that you do not take any more within 24 hours. This means you should not take Viagra in combination with any other ED tablets.

Find out more about how quickly Viagra works here.

Is Viagra safe?

While most men with erectile dysfunction should be able to use Viagra, there are some exceptions. Anyone who falls into the following categories should refrain from using Viagra or any other ED medicines.

Viagra is not safe for:

Men who are taking nitrates
Men who use recreational drugs that contain nitrates, such as poppers
Men who have severe heart or liver problems
Men who have recently had a stroke or heart attack
Men who have taken alpha-blockers within the past 6 hours
Men who have already taken Viagra or another type of ED medicine within the past 24 hours
Men who do not suffer from erectile dysfunction
Women

You should also be aware that Viagra should only ever be obtained through a prescription from a medical professional. Although many websites offer cheap erectile dysfunction medicines, it's almost impossible to ascertain where they came from and whether they are safe to take.

If you find that you are having unwanted side effects, or that the Viagra is not working for you, you may need to change your dosage. In the case of the latter, bear in mind that you will need to try a certain dosage of Viagra at least eight times before changing to a higher dosage as sometimes it takes a while to begin working.

What are the side effects of Viagra?

Most men can take Viagra without experiencing any side effects. However, as with all medicines, there are some risks. These include:

Nausea
Headache
Blocked nose
Indigestion
Flushing (redness in the face)
Dizziness
Blurred vision

For a full list of side effects, refer to the information on your medication. If you are experiencing frequent unpleasant side effects from Viagra, stop taking it and speak to your doctor.