8 Viagra (Sildenafil) Side Effects: How to Manage Flushing, Headaches, and More

Viagra (sildenafil) became the first FDA-approved medication of its kind in 1998. It’s used to treat erectile dysfunction (ED), which is when you have difficulty achieving or maintaining an erection for sex. Today it’s one of several ED medications in the same class.

Viagra is a phosphodiesterase 5 (PDE5) inhibitor. It works by causing more blood to flow to the penis for an erection. This can be beneficial for ED. But it can also cause side effects, such as headaches, flushing, and upset stomach. Serious side effects are rare, but they can happen too.

Viagra side effects at a glance

Viagra can cause mild side effects that usually resolve on their own. Higher doses are typically associated with an increased risk of side effects. In rare cases, serious side effects are possible.

Common or mild Viagra side effects include:

• Headache

• Flushing

• Dizziness

• Stomach upset (indigestion)

• Stuffy nose

• Nosebleed

• Nausea

• Back or muscle pain

• Skin rashes

Less common but serious Viagra side effects include:

• Vision changes, such as blurred or double vision

• Hearing changes, including hearing loss

• Low blood pressure (hypotension)

• Priapism (erection lasting over 4 hours)

Promotion disclosure

Viagra (Sildenafil)

Avg retail price

$165.68(Save 94.51%)

GoodRx discount

$9.10

See all discounts

How it works

Use GoodRx to find medications, pharmacies, and discounts.

GoodRx discounts can help you pay less for your prescription.

Bring your free coupon or savings card to the pharmacy.

Below, we’ll cover what you should know about eight Viagra side effects.

1. Headaches

Headaches are one of the most common Viagra side effects — reported by up to 28% of people in clinical trials. They can range from mild to more severe, including migraines or cluster headaches. The risk of headaches tends to go up with higher doses.

Viagra primarily affects blood vessels in the penis. But it can also affect blood vessels in other parts of your body. This has the potential to affect blood flow and cause chemical changes in the brain, which then lead to headaches.

Headaches from Viagra often resolve on their own. But here are a few tips for managing this side effect:

• Try an over-the-counter (OTC) pain reliever, such as acetaminophen (Tylenol).

• Stay hydrated, since dehydration can make headaches worse.

• Avoid or limit alcohol, which can increase the risk of headaches.

• Ask your prescriber about lowering your dose or other options if the headaches are severe or start affecting your quality of life.

2. Flushing

Flushing — skin that feels warm or appears red — is a common Viagra side effect. In initial studies, up to nearly 20% of people reported this reaction. It happens when Viagra widens blood vessels near the skin’s surface.

EXPERT PICKS: WHAT TO READ NEXT

• Is Viagra right for you? Several health conditions and interacting medications can make taking Viagra especially risky. Check to find out if these scenarios apply to you.

• Need help affording ED treatment? Here’s how you can save on your Viagra prescription.

• What to avoid: Learn about which medications and substances can be risky to combine with Viagra.

Similar to headaches, flushing is temporary and should go away on its own. Here are a few tips for managing it:

• Stay cool by avoiding hot environments or spicy foods after taking your dose.

• Dress in light layers if you tend to feel overheated.

• Stay hydrated, since this may help your body adjust.

3. Upset stomach

Upset stomach is possible with Viagra, reported by up to 17% of people. Viagra works by relaxing smooth muscles to improve blood flow, but it can also affect the muscles in your digestive tract. This can lead to indigestion and heartburn.

To prevent or manage stomach discomfort:

• Avoid heavy meals before taking Viagra, especially high-fat foods. They can delay the absorption of Viagra and potentially worsen side effects.

• Avoid or limit alcohol, since it can irritate your stomach and increase the risk of nausea or heartburn.

• Consider OTC options for relieving heartburn, such as antacids (e.g., Tums).

• Contact your prescriber if your upset stomach persists or becomes severe.

4. Stuffy nose

If you experience a stuffy nose after taking Viagra, you’re not alone. Because of how it works, Viagra can cause blood vessels to widen in your sinuses. This can cause congestion. But like most Viagra side effects, congestion is generally temporary and should go away on its own.

To manage a stuffy nose without affecting how Viagra works:

• Avoid OTC decongestants like pseudoephedrine (Sudafed). They constrict blood vessels and may interfere with erections.

• Try medication-free remedies, such as a hot shower, saline nasal spray, or a humidifier to relieve congestion naturally.

5. Nosebleeds

Some people taking Viagra report experiencing nosebleeds. This is thought to result from increased blood flow to nasal tissue.

To help manage or prevent nosebleeds from Viagra:

• Use a humidifier to keep your nasal passages moist, especially in dry environments.

• Avoid blowing your nose forcefully after taking Viagra.

• Try a saline nasal spray to reduce dryness and irritation.

If you get frequent nosebleeds after taking Viagra, tell your prescriber. They may lower your dose or recommend a different ED treatment. But if you experience a nosebleed that is severe or isn’t going away on its own, go to the ER.

6. Low blood pressure

Viagra can lower your blood pressure by relaxing blood vessels. For some people, this can lead to dizziness, lightheadedness, or weakness — especially around 1 hour after taking a dose. Blood pressure usually returns to normal within 4 hours.

To manage the risk of low blood pressure from Viagra:

• Avoid standing up too quickly after taking a dose.

• Sit or lie down until the feeling passes if you’re feeling dizzy or lightheaded.

• Stay hydrated and avoid alcohol, which can worsen dizziness.

• Monitor your blood pressure at home if you’re taking medications for high blood pressure. Ask about your blood pressure goal and what’s considered too low for you.

Don’t take Viagra if you’re taking nitrates or riociguat (Adempas). This combination can cause dangerously low blood pressure. Have your healthcare team review your medication list to flag interactions that can worsen low blood pressure with Viagra. Common examples include blood pressure medications and alpha blockers.

If you start experiencing low blood pressure symptoms, contact your healthcare team right away. Get immediate medical attention if you feel as if you’re going to pass out.

7. Prolonged erection

Viagra increases blood flow to the penis. But in rare cases, this effect can last too long. If blood doesn’t drain properly, it can cause a painful erection lasting more than 4 hours, known as priapism.

If this happens, go to the ER immediately. It might feel uncomfortable to seek help, but prompt treatment is critical. Delaying care or leaving priapism untreated can lead to permanent damage to your penis.

8. Vision changes

Viagra can also affect an enzyme (protein) that plays a role in how your eyes work. This is rare, but you may experience changes in your eyesight from the medication. This includes abnormal vision and vision loss.

Abnormal vision

A few potential eye effects include blurred vision, light sensitivity, and a change in how you see colors. You may notice a slight blue tinge in your vision. These effects are expected to be mild and short term.

Abnormal vision changes were reported by 3% to 11% of people taking Viagra in clinical trials. This side effect is more likely to happen with higher doses.

Vision loss

If you lose vision in one or both of your eyes, seek medical attention immediately. This may be a sign of nonarteritic anterior ischemic optic neuropathy (NAION). NAION is a type of vision loss that happens if there’s not enough blood flowing to the optic nerve, which sends messages between your eyes and your brain.

The risk of NAION appears to be doubled in men taking Viagra compared with everyone else. But it’s still rare. Most reported cases happened in people with other risk factors, such as age over 50, having heart problems, and high cholesterol. Having a “crowded” optic desk is also a risk factor.

If you have any changes in your eyesight, report them to your healthcare team for further assistance. Minor visual changes may improve by lowering your dosage.

Frequently asked questions

Why trust our experts?

Written by:

Brian Leonard, PharmD, BCACP, BCGP

Brian Leonard earned his doctorate in pharmacy from the University of Florida College of Pharmacy and is board certified in Ambulatory Care and Geriatric Pharmacy.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Our editorial standards

Meet our experts