Viagra's Side Effects: What to Know

Medically Reviewed By Tanya Kertsman, PharmD

Viagra: Introduction

Viagra is a brand-name prescription drug. It’s a type of medication called a phosphodiesterase-5 (PDE5) inhibitor and contains the active drug sildenafil. It comes as a tablet and is taken by mouth.

Viagra is approved by the Food and Drug Administration (FDA) to treat erectile dysfunction (ED) in adults. Viagra is typically used long term if you and your doctor agree that it’s safe and working well for you.

Similar to other drugs, Viagra may cause side effects. Read below for information about possible side effects, including common, mild, and serious ones.

For a general overview of Viagra, including details about its uses, see this article. If you’d like to take Viagra, search here to find a healthcare professional who might prescribe it.

Viagra: More common side effects

Some of Viagra’s side effects may be more common than others. These side effects may last a few days or weeks. However, some side effects may last longer or become severe or bothersome. Tell your doctor or pharmacist if you have concerns about any side effects with Viagra.

In Viagra’s clinical studies, these were some of the side effects that occurred more often:

  • flushing
  • indigestion
  • nausea
  • temporary vision changes, including blurry vision or blue-tinted vision
  • stuffy nose
  • back pain
  • muscle aches
  • dizziness
  • rash
  • headache*

* For more information about this side effect, see “Viagra: Side effects explained” below.

Viagra: Mild side effects

Viagra can cause mild side effects, which are listed below. However, this list doesn’t include all possible mild side effects. To learn more about Viagra’s side effects, view the drug’s prescribing information.

Viagra’s mild side effects include:

The side effects listed above may last only a few days to weeks. However, some side effects may last longer or become severe or bothersome. Tell your doctor or pharmacist if you have concerns about side effects with Viagra.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Viagra and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Viagra: Side effects explained” below.

Viagra: Serious side effects

It’s possible to have serious side effects with Viagra. Serious side effects are listed below, but this list may not include all possibilities. To learn more about Viagra’s side effects, view the drug’s prescribing information.

Call your doctor right away if you have serious side effects with Viagra. However, if you think you’re having a medical emergency or have life threatening side effects, call 911 or your local emergency number.

Serious side effects of Viagra and their possible symptoms include:

* For more information about this side effect, see “Viagra: Side effects explained” below.

Viagra: Common questions about side effects

Here are some common questions about Viagra’s side effects and their answers. Talk with your doctor if you have other questions about this drug.

Can Viagra cause long-term side effects?

It’s possible for treatment with Viagra to cause long-term side effects, but this is rare.

Long-term side effects are side effects that either:

  • start during treatment and continue for a long time, possibly after treatment ends, or
  • start after you’ve taken a drug for a long time or after ending treatment

Long-term side effects that have been reported with Viagra include:

These side effects could occur at any time while you’re taking Viagra, even if you’ve been taking the drug for a long time. However, stopping treatment with Viagra will remove your risk of these side effects. They aren’t expected to start in someone who has stopped taking the medication.

To learn more about Viagra and the risk of long-term side effects, talk with your pharmacist or doctor.

* For more information about this side effect, see “Viagra: Side effects explained” below.

Will men and women experience different side effects of Viagra?

Side effects of Viagra aren’t expected to differ in males and females.*

That said, keep in mind that Viagra is only approved for use in adult males. Clinical studies of Viagra didn’t include females.

However, another drug called Revatio contains the same active ingredient as Viagra, called sildenafil. Clinical studies of Revatio included males and females. Side effects reported in Revatio’s clinical studies were similar to those reported in Viagra’s clinical studies.

* Sex and gender exist on spectrums. In this article, the terms “male” and “female” refer to sex assigned at birth.

Is Viagra considered safe to take? Are there any dangers?

In general, Viagra is considered safe to take as prescribed by a doctor.

There are certain precautions to consider before taking Viagra. For example, people with certain medical conditions shouldn’t take the medication. To learn more, see the “Viagra: Precautions” section below.

To learn more about side effects Viagra may cause, view the “Viagra: Mild side effects” and “Viagra: Serious side effects” sections above. You can also talk with your pharmacist or doctor to learn more about the possible risks and benefits that you should consider before taking Viagra.

Does Viagra cause different side effects in older males?

Viagra isn’t expected to cause different side effects in older males.*

Viagra’s clinical studies included people ages 65 years and older. These studies didn’t find different side effects in this group compared with younger adults.

However, older males may be at higher risk of side effects from Viagra. Due to this risk, doctors will often prescribe a lower starting dose to older males. Your doctor can provide more information about your Viagra dose and your risk of side effects based on your age.

* Sex and gender exist on spectrums. In this article, the term “male” refers to sex assigned at birth.

If I take Viagra, will my partner experience any side effects?

No, Viagra shouldn’t cause your partner to experience side effects. The drug won’t enter your partner’s system, so only the person who takes a dose of Viagra is at risk of side effects.

Viagra: Side effects explained

Here’s detailed information about some of Viagra’s side effects.

Headache

Headache is a possible side effect of Viagra. In fact, it was the most common side effect in the drug’s clinical studies. People who took a higher Viagra dose in these studies were more likely to report headache as a side effect compared with people who took lower doses.

Headache can also be a symptom of low blood pressure, a rare but possibly serious side effect of Viagra.

What to do

Talk with your doctor if you’re experiencing headaches after taking doses of Viagra. Your doctor may recommend using an over-the-counter pain reliever, such as acetaminophen (Tylenol), to relieve your symptoms. However, if you’re having recurring headaches, especially ones that affect your daily living, your doctor may suggest that you stop taking Viagra.

Low blood pressure

Low blood pressure is a possible side effect of Viagra. It usually isn’t serious. In the drug’s clinical studies, temporary and mild low blood pressure was common.

Rarely, low blood pressure from Viagra can be serious. This is most likely to happen in people with certain conditions, such as:

  • conditions that cause problems regulating blood pressure, such as dysautonomia
  • aortic stenosis (narrowing of the aortic valve in your heart)
  • high or low blood pressure
  • heart disease, including:

Symptoms of low blood pressure can include:

  • feeling dizzy, faint, or lightheaded
  • dry mouth
  • weakness
  • decreased amount of urine

What to do

Due to this risk, your doctor will evaluate your heart health to determine if it’s safe to prescribe Viagra. Be sure to discuss your complete medical history with your doctor before taking Viagra.

If you notice symptoms of low blood pressure after taking Viagra, call your doctor. They can determine whether it’s safe for you to continue taking the medication.

Prolonged erection

In rare cases, taking Viagra may cause an erection that lasts longer than 4 hours. In Viagra’s clinical studies, this included priapism, which is a painful erection that lasts longer than 6 hours.

With a prolonged erection, blood becomes trapped in the penis and is unable to flow away from the penis. This can lead to permanent damage if not treated immediately.

Symptoms can include:

  • prolonged erection that is unrelated to sexual activity
  • worsening pain in the penis

Having certain medical conditions may place you at higher risk of this side effect of Viagra, including:

What to do

Immediately seek emergency medical help if you experience an erection lasting 4 or more hours after taking Viagra. If not treated right away, prolonged erection can result in damage to the penis or permanent erectile dysfunction.

If you experience a prolonged erection after taking Viagra, your doctor will determine whether it’s safe for you to continue taking the medication.

Cardiovascular problems, including heart attack or stroke

There have been reports of cardiovascular problems in people taking Viagra. In the drug’s clinical studies, these problems were rare. So researchers aren’t entirely sure whether they were due to taking Viagra or another cause.

Cardiovascular problems that Viagra may rarely cause include:

Symptoms of heart attack, irregular heartbeat, or heart failure can include:

  • chest pain, which may spread to your back, shoulder, jaw, neck, or arm
  • shortness of breath
  • feeling dizzy or lightheaded
  • nausea
  • unintentional rapid weight gain

Symptoms of a stroke can include:

  • inability to speak
  • weakness or paralysis, particularly on one side of your body
  • problems with coordination or balance

Certain people may be at higher risk of cardiovascular problems if they take Viagra. This includes people with:

  • heart attack, stroke, or life threatening arrhythmia in the past 6 months
  • heart failure
  • unstable angina
  • high blood pressure or low blood pressure

What to do

Due to this risk, your doctor will evaluate your heart health in order to determine if it’s safe to prescribe Viagra to you.

If you have symptoms of a cardiovascular problem after taking Viagra, call 911 or a local emergency number. Heart attack, stroke, or other heart problems can be life threatening and require medical treatment right away.

If you experience a cardiovascular problem after taking Viagra, your doctor will determine whether it’s safe for you to continue treatment with the medication.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Viagra. A more severe allergic reaction is rare but possible.

Possible symptoms of mild and serious allergic reactions are listed in the table below.

Mild allergic reaction symptoms Serious allergic reaction symptoms
• itching trouble breathing
rash • swelling in your throat or mouth
flushing • swelling under your skin, possibly in your hands, feet, lips, or eyelids

If you have an allergic reaction to Viagra, call your doctor right away. This is important because the reaction could become severe.

However, if you’re having a medical emergency or your symptoms feel life threatening, call 911 or your local emergency number.

Viagra: Precautions

Be sure to talk with your doctor about your health history before taking Viagra. This drug may not be the right treatment option if you have certain medical conditions or other factors that affect your health.

Some of the conditions and factors to consider include those described below.

Heart problems, including high or low blood pressure. Treatment with Viagra can cause certain side effects, including low blood pressure and heart attack. You may be at higher risk of these side effects if you have a heart problem such as high blood pressure or a life threatening arrhythmia (abnormal heart rhythm). Your doctor can determine whether your heart is healthy enough for treatment with Viagra.

Stroke in the past. Rarely, treatment with Viagra may cause stroke as a side effect. If you’ve had a stroke in the past, you may be at higher risk of this side effect if you take Viagra. Additionally, it’s not known whether it’s safe to take Viagra within 6 months of having a stroke. Your doctor can determine whether it’s safe for you to take Viagra.

Irregular penis shape. Having an irregular penis shape, such as a curvature caused by Peyronie’s disease, can raise your risk of a prolonged erection after taking Viagra. This is a serious side effect that can result in permanent penile damage. Your doctor can tell you more about whether it’s safe for you to take Viagra.

Prolonged erection in the past. If you’ve experienced a prolonged erection (an erection lasting longer than 4 hours) in the past, be sure to let your doctor know before you take Viagra. Viagra can cause a prolonged erection as a side effect in rare cases. It’s not known whether you’re at higher risk of this side effect if you’ve experienced a prolonged erection in the past. Your doctor can tell you more about whether it’s safe for you to take Viagra.

Blood cell problems, such as sickle cell anemia, multiple myeloma, or leukemia. Having certain blood cell problems may raise your risk of a prolonged erection, a rare but serious side effect of Viagra. Examples of these blood cell problems include sickle cell anemia, multiple myeloma, and leukemia. Your doctor can tell you more about whether it’s safe for you to take Viagra.

Eye problems, including retinitis pigmentosa or non-arteritic anterior ischemic optic neuropathy (NAION). Rarely, Viagra can cause eye-related side effects, including temporary or permanent vision loss. It’s important to let your doctor know if you have an existing eye problem. Especially let your doctor know if you have retinitis pigmentosa or NAION, which is a condition that can damage your optic nerve. Your doctor can determine whether Viagra is safe for you to take.

Kidney or liver problems. Be sure to let your doctor know if you have a kidney or liver problem before you take Viagra. Your doctor will likely prescribe a lower starting dose of the drug if you have certain kidney or liver problems. Examples of these problems include chronic kidney disease or cirrhosis.

Allergic reaction. If you’ve had an allergic reaction to Viagra or any of its ingredients, your doctor will likely not prescribe Viagra. Ask your doctor what other medications may be better options for you.

Consuming alcohol during Viagra treatment

There’s no known interaction between consuming alcohol and taking Viagra.

However, Viagra and alcohol can cause similar side effects, including headache, dizziness, and nausea. Combining the two may raise your risk of these side effects.

In addition, alcohol may cause difficulties in having or maintaining an erection. Viagra is prescribed to treat erectile dysfunction (ED). So Viagra may not work as well if you take it while drinking alcohol.

Talk with your doctor to learn more about the risks of consuming alcohol while you’re taking Viagra.

Pregnancy and breastfeeding during Viagra treatment

It’s not known if it’s safe to take Viagra while pregnant or breastfeeding. Viagra is only approved for use in males.*

Talk with your doctor if you have questions about Viagra and taking it while pregnant or breastfeeding.

* Sex and gender exist on spectrums. In this article, the term “male” refers to sex assigned at birth.

Viagra: What to discuss with your doctor

Talk with your doctor or pharmacist for additional information about Viagra. If you have questions about the drug’s side effects, your pharmacist or healthcare professional can help answer them.

In addition to discussing Viagra with your doctor, you may find the following articles helpful in learning more.

  • Overview of Viagra. To read an overview of Viagra, see this article.
  • Drug comparison. To learn how Viagra compares with Cialis, read this article.
  • Information on dosage. If you’d like to know about Viagra’s dosage, view this article.
  • Details about erectile dysfunction (ED). To learn more about ED, which Viagra is used to treat, see this article.

Disclaimer: Healthgrades has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

Medical Reviewer: Tanya Kertsman, PharmD
Last Review Date: 2022 Aug 13
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.