Viagra Side Effects On The Body And FAQs - Healthline

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Viagra side effects

Viagra may cause some unwanted side effects.

Side effects may include:

sensitivity to light
muscle aches
heartburn
nose bleeding
flushed skin
problems falling asleep
tingling in the arms, feet, legs, or hands
numbness in the arms, feet, legs, or hands
headache
diarrhea
heartburn
trouble differentiating between colors like blue and green
seeing a blue tinge on things

Viagra may also cause serious side effects that require immediate medical attention. Symptoms may include:

chest pain
fainting
blurred vision
severe, sudden loss of vision
ringing in ears
sudden loss of or decrease in hearing
dizziness
rash
burning during urination
itching during urination
shortness of breath that worsens
an erection that lasts longer than 4 hours and may be painful

Hand drawn diagram of male body with text about viagra side effects — Illustration by Anthony Agreste

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

Viagra is a brand-name version of the generic drug sildenafil. It’s a phosphodiesterase type 5 (PDE5) inhibitor. PDE5 is an enzyme that regulates certain chemicals in your blood, but because of its effect on the body, it can make it harder for you to get and keep an erection.

Viagra 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. It does not affect sexual desire either. You still need mental or physical stimulation to get an erection.

This medication is only available with a doctor’s prescription.

Information on dosages

The appropriate dosage of Viagra may vary between people. Your doctor will be able to determine the proper dosage for you.

The number of doses taken daily depends on why Viagra is being used. Viagra is taken orally.

For use in erectile dysfunction:

Adults aged up to 64 years old typically take 50 milligrams (mg) 1 hour before sexual intercourse, no more than once a day.
For adults ages 65 and older using Viagra for erectile dysfunction, or for those with cirrhosis or severe renal impairment, the average dose is 25 mg as a single dose, taken 1 hour before sexual intercourse, but no more than once a day.

Viagra may also be taken between 30 minutes to 4 hours before sexual intercourse.

Your doctor may adjust your dosage to meet your needs.

Viagra may also be used for pulmonary arterial hypertension. When used for this purpose, the average dose is 5 to 20 mg of Viagra taken 3 times a day. The doses of Viagra should be taken between 4 to 6 hours apart when used for pulmonary arterial hypertension.

Age	Dosage	When to take
Adults ages up to 64 years old	50 mg, no more than once a day	1 hour prior to sexual intercourse (alternatively, may also be taken between 30 minutes and 4 hours prior to sexual intercourse)
Adults ages 65 and older, or with cirrhosis or severe renal impairment	25 mg, no more than once a day	1 hour prior to sexual intercourse (alternatively, may also be taken between 30 minutes and 4 hours prior to sexual intercourse)

Circulatory system

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

Within the penis are two chambers called the corpora cavernosa. Nitric oxide is released in the chambers during sexual stimulation. Nitric oxide activates an enzyme called guanylate cyclase. This increases cyclic guanosine monophosphate (cGMP) levels, 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.

PDE5 can dampen the effect of cGMP. Viagra works by inhibiting PDE5.

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

One of the more common side effects is flushing, redness or other color changes, or other discoloration.

This medication can also cause a decrease in blood pressure, particularly 1 to 2 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, ask your doctor if it’s safe for you to take Viagra. You should also avoid Viagra if your doctor advises you not to have sex.

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

Certain drug interactions can harm your heart. Avoid taking PDE5 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 the libido. You still need some kind of stimulation to get an erection.

The effects of Viagra usually last about 4 hours, though they may last longer for some men. A rare but serious side effect is priapism. That’s when you get an erection that lasts for an extended period of time. It can become quite painful.

If you have an erection that lasts for more than 4 hours, seek immediate medical attention.

You should also be wary of PDE5 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 infections (STIs).

Central nervous system

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

Some potential side effects of Viagra are headache, runny or blocked nose, or a nosebleed. Some men feel lightheaded or dizzy. In rare cases, Viagra can cause fainting. Some men taking PDE5 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 PDE5 inhibitors.

Avoid PDE5 inhibitors if you have a history of non-arteritic anterior ischemic optic neuropathy (NAION), an eye condition characterized by the interruption of blood flow to the optic nerve.

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

Excretory and digestive system

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

Do not take Viagra more than once per day.

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

One fairly common side effect of Viagra is indigestion or stomach upset. PDE5 inhibitors can sometimes cause nausea or vomiting.

Frequently asked questions

How long do the effects of Viagra last?

Viagra typically lasts between 2 and 5 hours before the effects start to wear off. It’s important to make sure to take this medication correctly and, ideally, take the tablet 30 to 60 minutes before you plan to engage in sexual activity. It’s also important to keep in mind that you must be sexually aroused for the tablet to work properly.

Will Viagra make you bigger?

Viagra is a drug that works by helping men maintain an erection. Without touch to the penis, like that experienced in sexual intercourse, an erection will not occur, and the penis will not harden or grow in size.The effects of Viagra on the body are temporary and will not result in a permanently hard or enlarged penis. In rare cases, some men may experience a prolonged erection that is painful. This requires professional medical attention.

The effects of Viagra on the body are temporary and will not result in a permanently hard or enlarged penis. In rare cases, some men may experience a prolonged erection that is painful. This requires professional medical attention.

Does Viagra keep you hard after coming?

What are the side effects of taking too much Viagra?

In studies of healthy participants taking up to 800 mg of Viagra, there were similar adverse reactions as those found at a lower dosage. However, the incidence of some adverse reactions and the severity of adverse reactions increased with the dosage of Viagra.

Possible adverse reactions from Viagra include:

headache
abnormal vision
flushing
dyspepsia
nasal congestion
nausea
dizziness
rash
back pain
muscle aches and pains

There are a few common side effects that can result from Viagra. These include:

lightheadedness
nausea
change in vision

If these symptoms become severe, contact your doctor immediately.

More severe side effects from Viagra can include:

prolonged erections
loss of vision
loss of hearing

Seek immediate medical attention if you are experiencing these symptoms.

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What to do if you’re experiencing Viagra side effects

For severe side effects from Viagra, stop using the drug immediately and seek medical attention.

For more common side effects, talk with your doctor about changing your dosage of the drug.

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Erectile dysfunction (impotence) — treatment. (2023).https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/
Sildenafil. (2023).https://medlineplus.gov/druginfo/meds/a699015.html
Viagra sildenafil citrate tablet, film coated. (2022).https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=a2a9f459-e692-4e85-83b0-a35fbf35e91b
Viagra (sildenafil citrate) tablets, for oral use. (2014).https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/20895s039s042lbl.pdf
What is the refractory period? (n.d.).https://www.issm.info/sexual-health-qa/what-is-the-refractory-period/

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Medically reviewed by Alex Nguyen, PharmD, RPh, CPh — Written by Ann Pietrangelo — Updated on May 23, 2025

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Viagra side effects

Information on dosages

Circulatory system

Reproductive system

Central nervous system

Excretory and digestive system

Frequently asked questions

How long do the effects of Viagra last?

Will Viagra make you bigger?

Does Viagra keep you hard after coming?

What are the side effects of taking too much Viagra?

What to do if you’re experiencing Viagra side effects

How we reviewed this article:

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