Viagra (sildenafil)

Viagra is a brand-name prescription drug that’s approved to treat erectile dysfunction (ED). With ED, you’re unable to have or maintain an erection. Viagra is approved for this use in males ages 18 years and older.

Viagra contains the drug sildenafil. It belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. (A class of drugs is a group of medications that act in a similar way.) Viagra works by increasing blood flow to your penis, which helps you have and keep an erection. But this drug only works if you’re sexually aroused.

Viagra comes as tablets that are taken by mouth. In most cases, it should be taken about an hour before sexual activity, but it can be taken 30 minutes to 4 hours beforehand. Viagra is available in three strengths: 25 mg, 50 mg, and 100 mg.

Does Viagra work to treat ED?

Yes, it does. In several clinical studies, Viagra was effective in treating ED. In these studies, men who used the drug had an improved ability to have and keep erections that allowed for successful sex.

Across the studies, between 43% and 83% of men who took Viagra had improved erections. (These rates varied depending on the cause of their ED and the dosage of Viagra being used.) In comparison, improved erections occurred in 10% to 24% of men who took a placebo (no active drug).

To learn more about Viagra’s effectiveness, see the “Viagra uses” section below.

Generic versions of Viagra are available. A generic drug is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. Generics tend to cost less than brand-name drugs.

Viagra contains the active drug sildenafil.

Viagra can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Viagra. These lists don’t include all possible side effects.

For more information on the possible side effects of Viagra, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to report to the FDA a side effect you’ve had with Viagra, you can do so through MedWatch.

Mild side effects

Mild side effects of Viagra can include:*

  • headache
  • flushing
  • indigestion
  • mild and temporary vision changes, such as a blue tinge in your vision, blurred vision, and sensitivity to light
  • nasal congestion (stuffy nose)
  • back pain
  • muscle pain
  • nausea
  • dizziness
  • rash

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

* This is a partial list of mild side effects from Viagra. To learn about other mild side effects, talk with your doctor or pharmacist, or view the drug’s patient information.

Serious side effects

Serious side effects from Viagra aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects and their symptoms can include:

  • Non-arteritic anterior ischemic optic neuropathy (NAION), which is an eye condition that causes damage to your optic nerve. Symptoms can include:
    • sudden decrease in vision in one or both of your eyes
    • sudden loss of vision in one or both of your eyes
  • Sudden decrease or loss of hearing. This condition may also involve other symptoms, such as:
    • tinnitus (ringing or buzzing in your ears)
    • dizziness

Other serious side effects, which are explained in more detail below in “Side effect details,” include:

  • allergic reaction
  • priapism (long-lasting and sometimes painful erection)
  • low blood pressure, if Viagra is taken with certain other medications
  • cardiovascular problems, such as heart attack, irregular heartbeat, or stroke, all of which occur mainly in people with heart disease

Side effect details

You may wonder how often certain side effects occur with this drug. Here’s some detail on several of the side effects this drug may cause.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Viagra. In clinical studies, less than 2% of people who took Viagra had an allergic reaction. It’s not known how often allergic reactions occurred in people who took a placebo (no active drug).

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (warmth and redness in your skin)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have a severe allergic reaction to Viagra. But call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Priapism

Rarely, Viagra can cause priapism, which is a long-lasting and sometimes painful erection. But it’s not known how often priapism occurs in men who take Viagra.

Priapism is a medical emergency that needs to be treated right away. If it’s not treated, the condition can damage the tissues in your penis and cause irreversible erectile dysfunction (ED).

If you have an erection that lasts longer than 4 hours, go to the nearest emergency room or call 911.

Low blood pressure

Viagra can temporarily lower your blood pressure after you take the drug. But this isn’t a problem for most people. In clinical studies, less than 2% of people who took Viagra had low blood pressure after taking the drug. It’s not known how often low blood pressure occurred in people who took a placebo (no active drug).

But keep in mind that a sudden drop in your blood pressure could be dangerous if you have certain heart conditions. Sudden low blood pressure may also be dangerous if you’re taking certain other medications.

For example, you shouldn’t take Viagra if you take nitrate medications to treat chest pain. You should also avoid taking Viagra if you take a drug called riociguat (Adempas). Taking Viagra with these medications can cause a dangerous drop in your blood pressure that leads to heart attack or stroke.

If you have low blood pressure, taking Viagra could make you feel dizzy or lightheaded, or cause you to faint. You’re also more likely to have these problems if you take Viagra with certain drugs used to treat high blood pressure or enlarged prostate. If you feel dizzy or faint after taking Viagra, lie down until this feeling passes.

If you have a heart problem or low blood pressure, talk with your doctor about whether Viagra is safe for you.

For more information about taking Viagra with other medications, see the “Viagra interactions” section below. And for more information about taking Viagra if you have heart or blood pressure problems, see the “Viagra precautions” section below.

Heart attack, irregular heartbeat, and stroke

On rare occasions, some people taking Viagra have had heart attack, stroke, or irregular heartbeat. These conditions mainly occurred in people who already had a heart problem. But sometimes these conditions occurred in people who didn’t have a heart problem. It’s not known for sure if Viagra caused the side effects.

If you have chest pain after taking Viagra, you should stop having sexual activity right away. But call 911 if your symptoms feel life threatening, or if you think you’re having a medical emergency.

And if you have a heart problem, talk with your doctor before starting Viagra. They can discuss with you whether it’s safe for you to use this drug. For more information about taking Viagra if you have heart problems, see the “Viagra precautions” section below.

Headaches

Headaches are a common side effect of Viagra. Headaches, as well as flushing and dizziness, occur because Viagra widens certain blood vessels in your body. (The drug doesn’t just affect the blood vessels in your penis.)

In clinical studies, headaches were reported in 16% to 28% of people who took Viagra. (This percentage varied depending on the dose of Viagra used and how often the drug was taken.) In comparison, headaches were reported in 4% to 7% of people who took a placebo (no active drug).

If you have a headache after taking Viagra, it should go away fairly quickly. But if it’s bothersome, you can take a pain reliever containing acetaminophen or ibuprofen. Ask your doctor or pharmacist to recommend a medication that’s safe for you to use.

If you have a severe headache or a headache that won’t go away, call your doctor. They’ll help determine the best treatment for your headache.

Side effects in older men

Men ages 65 years and older tend to get higher levels of Viagra in their blood after taking a dose than younger men do. Having a higher level of the drug in your body could increase your risk of side effects. Because of this, older men are usually prescribed a dosage of Viagra that’s lower than the dosage given to younger men.

In clinical studies of Viagra, there weren’t any differences in side effects seen in men ages 65 years and older compared with those in men younger than 65 years.

If you have concerns about using Viagra given your age, talk with your doctor.

Erectile dysfunction (ED)

Taking Viagra doesn’t cause new or worsening ED. However, Viagra can sometimes cause priapism, which is a long-lasting and sometimes painful erection.

Priapism is a medical emergency that needs to be treated right away. If it’s not treated, priapism can damage the tissues in your penis and cause irreversible ED.

If you have an erection that lasts longer than 4 hours, you should immediately go to an emergency room or call 911.

How to relieve Viagra side effects

Most of the mild side effects of Viagra either tend to go away within a few hours of taking your dose or can be easily relieved.

For example, headaches, flushing, and dizziness can often be eased by lying down and resting. Avoiding alcohol will also help reduce these side effects. Headaches and sensitivity to light can also be improved by turning off any bright lights around you. If you have bothersome headaches with Viagra, ask your doctor or pharmacist to recommend a pain reliever that’s safe for you to use.

If you get indigestion after taking Viagra, try taking your dose of Viagra with a snack or light meal. Just be aware that if you do this, Viagra may take slightly longer to start working for you. (This is especially true if you eat a high-fat meal with your dose.) If your indigestion is bothersome, ask your doctor or pharmacist to recommend medication to help reduce your discomfort.

Also keep in mind that certain side effects occur more often with higher doses of Viagra. These side effects include headaches, flushing, indigestion, nasal congestion, and changes in your vision. So if these side effects are a problem for you, talk with your doctor about taking a lower dosage of Viagra.

When to call your doctor

Don’t forget that some of Viagra’s rare side effects need immediate medical attention. For example, you should call your doctor right away if you have:

  • an erection that doesn’t go away and lasts for more than 4 hours
  • chest pain, dizziness, or nausea while you’re having sex, and these symptoms don’t go away when you stop having sex and begin to rest
  • sudden loss of vision in one or both of your eyes
  • sudden decrease or loss of hearing

The Viagra dosage your doctor prescribes will depend on several factors. These include:

  • your age
  • whether you have liver or kidney problems
  • other medical conditions you may have
  • other medications you may be taking

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Drug forms and strengths

Viagra comes as tablets that are taken by mouth. It’s available in three strengths: 25 mg, 50 mg, and 100 mg.

Dosage for ED

The typical dose of Viagra for erectile dysfunction (ED) is 50 mg. You can take this dose 30 minutes to 4 hours before you plan to have sexual activity. But for most people, it’s recommended that you take your dose about an hour before having sex. Don’t take Viagra more than once a day.

Your doctor may prescribe a different dosage of Viagra for you depending on several factors. These factors may include whether you have liver or kidney problems, or if you’re taking certain other medications. If any of these factors apply to you, your starting dose might be 25 mg, which is lower than the typical recommended dose.

If you have questions about the Viagra dosage that’s right for you, talk with your doctor.

And keep in mind that if Viagra isn’t working for you, your doctor may increase your dose of the drug. But the maximum dose of Viagra is 100 mg.

Dosage questions

Below, we answer some common questions related to Viagra’s dosage.

Is Viagra’s dosage based on age or weight?

Your dosage of Viagra won’t be based on your weight, but it may be based on your age.

For example, people ages 65 years and older tend to get higher levels of Viagra in their blood after taking a dose. So, if you’re over 65 years of age, your doctor will usually recommend a starting dose of Viagra for you that’s lower than the typical starting dose. For example, they may recommend that you take 25 mg of the drug rather than 50 mg.

Can I take Viagra just for fun, even if I don’t have ED? If so, how much is safe to take?

No, you shouldn’t take Viagra if you don’t have ED. Viagra is a prescription medication that can have serious side effects. And it’s approved only to treat ED, not to be used recreationally.

You should only take Viagra if it’s been prescribed to you by a doctor who knows your medical history.

Will I need to use this drug long term?

Maybe. If you and your doctor determine that Viagra is safe and effective for you, you can likely take it for as long as you continue to need it.

Other drugs are available that can treat erectile dysfunction (ED). Some may be a better fit for you than others. If you’re interested in finding an alternative to Viagra, talk with your doctor. They can tell you about other medications that may work well for you.

Examples of other drugs that may be used to treat ED include:

  • tadalafil (Cialis)
  • vardenafil (Levitra, Staxyn)
  • avanafil (Stendra)
  • alprostadil (Caverject, Caverject Impulse, Edex, Muse)
  • testosterone therapy, which is only used if you have low levels of testosterone

Natural and over-the-counter alternatives for ED

Natural and over-the-counter (OTC) products for treating ED are widely available, especially on the internet. However, none of these products has been tested for safety or effectiveness by the Food and Drug Administration (FDA).

And because the products aren’t regulated, the FDA warns that there’s no way to be certain of what these products actually contain. If you want to try a natural or OTC product for ED, you should first discuss it with your doctor.

The American Urological Association doesn’t recommend using products that contain yohimbine, ginseng, and l-arginine for ED treatment. (This includes products that contain these ingredients either alone or in combination with other ingredients.) This is because there’s not enough evidence to say whether the products work. And these products may cause harmful side effects.

Examples of products that contain one or more of these ingredients include Libido-Max and Extenze.

Products that claim to contain sildenafil

You should also avoid products you can buy online without a prescription that claim either to be generic forms of sildenafil or to contain sildenafil. (Sildenafil is the active drug in Viagra.)

If these drugs are available without a prescription, that means that they haven’t been tested or approved by the FDA. As a result, it’s not known if they’re effective or even safe. And there’s no guarantee that the products actually contain sildenafil.

You may wonder how Viagra compares with other medications that are prescribed for similar uses. Here we look at how Viagra and Cialis are alike and different.

Ingredients

Viagra contains the drug sildenafil, while Cialis contains the drug tadalafil. Both Viagra and Cialis belong to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. (A class of drugs is a group of medications that work in a similar way.)

Viagra and Cialis are both approved to treat erectile dysfunction (ED) in males ages 18 years and older. These drugs work to treat ED by helping you have and maintain an erection when you’re sexually aroused. But the drugs don’t work if you’re not aroused.

In addition, Cialis is approved to treat symptoms caused by benign prostatic hyperplasia (BPH).* These symptoms include needing to pass urine frequently or urgently. They can also include having a weak flow of urine or being unable to fully empty your bladder.

* With BPH, you have an enlarged prostate.

Drug forms and administration

Viagra and Cialis both come as tablets that are taken by mouth.

With Viagra, you’ll take the drug between 30 minutes and 4 hours before you plan to have sex. The medication can help you get an erection for up to 4 hours after you’ve taken a dose. Viagra shouldn’t be taken more than once a day.

With Cialis, you’ll take a dose at least 30 minutes before you plan to have sex. This medication can help you get an erection for up to 36 hours after you’ve taken a dose. Cialis shouldn’t be taken more than once a day.

While you can take Cialis just as needed for ED treatment, another option is to take a low dose of the drug regularly each day. Doing this can help you to get an erection at any time when you’re sexually aroused. This may help make sex more spontaneous for you.

Side effects and risks

Viagra and Cialis both contain the same type of drug. Therefore, these medications can cause very similar side effects. Below are examples of these side effects.

Mild side effects

These lists contain up to 10 of the most common mild side effects that can occur with Viagra, with Cialis, or with both drugs (when taken individually).

  • Can occur with Viagra:
    • mild and temporary vision changes, such as a blue tinge to your vision, blurred vision, or sensitivity to light
    • nausea
    • dizziness
    • rash
  • Can occur with Cialis:
    • pain in your arms or legs
    • upper respiratory tract infection
    • cough
    • diarrhea
  • Can occur with both Viagra and Cialis:
    • headache
    • flushing
    • indigestion
    • nasal congestion (stuffy nose)
    • back pain
    • muscle pain

Serious side effects

The following list contains examples of serious side effects that can occur with either Viagra or Cialis.

  • allergic reaction
  • priapism (long-lasting and sometimes painful erection)
  • non-arteritic anterior ischemic optic neuropathy (NAION), which is an eye condition that causes damage to your optic nerve
  • sudden hearing loss
  • low blood pressure, if the drugs are taken with certain other medications
  • cardiovascular problems, such as heart attack, irregular heartbeat, and stroke, all of which mainly occur in people with heart disease

Effectiveness

Viagra and Cialis have different approved uses, but they’re both used to treat ED.

The use of Viagra and Cialis in treating ED has been directly compared in several clinical studies. One review of these studies found the two drugs were similarly effective in improving men’s ability to have and maintain erections.

However, researchers found that men who took Cialis had improved confidence in their sexual ability. So the men were more likely to prefer Cialis over Viagra. This is likely due to the long-lasting effect of Cialis, which allows men to have more spontaneous sex. (Cialis’s dosing schedule allows less planning for when a dose is needed before having sex.)

The study also found that men who took Cialis were more likely to have back or muscle pain than were men taking Viagra. But men taking Cialis were less likely to have flushing compared with men taking Viagra.

Costs

Viagra and Cialis are both brand-name drugs. Generic forms of both drugs are available. Brand-name medications usually cost more than generics.

According to estimates on GoodRx.com, Viagra and Cialis generally cost about the same. The actual price you’ll pay for either drug depends on your insurance plan, your location, your prescribed dosage, and the pharmacy you use.

Sildenafil is the active drug in Viagra. In addition to being available as the brand-name drug Viagra, it’s available as a generic drug. Here we look at how Viagra and sildenafil are alike and different.

Ingredients

Viagra, which contains the active drug sildenafil, is a brand-name drug. But sildenafil is also available as a generic medication.

A generic medication is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. Generics tend to cost less than brand-name drugs.

Drug forms and uses

Viagra is approved to treat erectile dysfunction (ED) in males ages 18 years and older. It comes as tablets that are taken by mouth. Viagra is available in the following strengths:

Like Viagra, certain forms of sildenafil are approved to treat ED in males ages 18 years and older. For example, sildenafil 25-mg, 50-mg, and 100-mg tablets are approved for this use.

In addition, sildenafil also comes as 20-mg tablets. Sildenafil is also available as a liquid suspension that’s taken by mouth and as a solution that’s given by injection. These forms of sildenafil are generic versions of a brand-name drug called Revatio. But unlike Viagra, they’re not used to treat ED.

Like Revatio, these forms of sildenafil are used to treat a condition called pulmonary arterial hypertension (PAH). With PAH, you have high blood pressure in the artery between your heart and lungs.

Effectiveness and safety

The Food and Drug Administration (FDA) considers generics to be just as safe and effective as the original drug. This means that generic sildenafil is just as effective in treating ED as Viagra is when it’s used at the same doses as Viagra is used. It also means that sildenafil and Viagra can cause the same side effects.

For information on the possible side effects of Viagra, see the section “Viagra side effects” above.

Costs

Viagra is a brand-name drug, while sildenafil is a generic form of Viagra. Brand-name medications usually cost more than generics.

According to estimates on GoodRx.com, sildenafil generally costs much less than Viagra costs. The actual price you’ll pay for either drug depends on your insurance plan, your location, and your prescribed dosage.

Like Cialis (described above), Levitra is also prescribed for similar uses as Viagra. Here we look at how Viagra and Levitra are alike and different.

Ingredients

Viagra contains the drug sildenafil, while Levitra contains the drug vardenafil. Both Viagra and Levitra belong to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. (A class of drugs is a group of medications that work in a similar way.)

Viagra and Levitra are both approved to treat erectile dysfunction (ED) in males ages 18 years and older. These drugs work to treat ED by helping you have and maintain an erection when you’re sexually aroused. But the drugs don’t work if you’re not aroused.

Drug forms and administration

Viagra and Levitra both come as tablets that are taken by mouth.

With Viagra, you’ll take a dose between 30 minutes and 4 hours before you plan to have sex. With Levitra, you’ll take a dose about 1 hour before sexual activity. The medications can help you get an erection for up to 4 hours after you take a dose. But neither drug should be taken more than once a day.

Side effects and risks

Viagra and Levitra both contain the same type of drug. Therefore, these medications can cause very similar side effects. Below are examples of these side effects.

Mild side effects

These lists contain up to 10 of the most common mild side effects that can occur with Viagra, with Levitra, or with both drugs (when taken individually).

  • Can occur with Viagra:
    • mild and temporary vision changes, such as a blue tinge to your vision, blurred vision, or sensitivity to light
    • rash
    • muscle pain
  • Can occur with Levitra:
    • sinusitis (inflammation in your sinuses)
    • flu-like symptoms, such as fever, chills, and body aches
  • Can occur with both Viagra and Levitra:
    • headache
    • flushing
    • indigestion
    • nasal congestion (stuffy nose)
    • nausea
    • dizziness
    • back pain

Serious side effects

The following list contains examples of serious side effects that can occur with either Viagra or Levitra.

  • allergic reaction
  • priapism (long-lasting and sometimes painful erection)
  • non-arteritic anterior ischemic optic neuropathy (NAION), which is an eye condition that causes damage to your optic nerve
  • sudden hearing loss
  • low blood pressure, if the drugs are taken with certain other medications
  • cardiovascular problems, such as heart attack, irregular heartbeat, and stroke, all of which occur mainly in people with heart disease

Effectiveness

The only condition both Viagra and Levitra are used to treat is ED.

The use of Viagra and Levitra in treating ED has been directly compared in several clinical studies and compared in several reviews of studies. Based on study information, the American Urological Association considers Viagra and Levitra to be similarly effective in improving men’s ability to have and maintain erections.

Costs

Viagra and Levitra are both brand-name drugs. Generic forms of both drugs are available. Brand-name medications usually cost more than generics.

According to estimates on GoodRx.com, Viagra costs more than Levitra costs. The actual price you’ll pay for either drug depends on your insurance plan, your location, and the pharmacy you use.

You may wonder how long Viagra works when it’s used to treat erectile dysfunction (ED). Below, we answer questions related to how long Viagra works inside your body.

If you have other questions about how long Viagra works, talk with your doctor.

How long does Viagra take to work?

Viagra typically starts to work between 30 and 60 minutes after you take a dose of the drug. But Viagra itself doesn’t give you an erection. Instead, you’ll need to be sexually aroused in order for the drug to work.

Viagra keeps working in your body for up to 5 hours. This means that if you’re aroused, you should be able to achieve an erection for up to 4 hours after taking a dose of Viagra.

Even though Viagra keeps working in your body for several hours, your erection shouldn’t last this long. In fact, rarely, Viagra can cause priapism. With this condition, you have a long-lasting and sometimes painful erection.

Priapism is a medical emergency that needs to be treated right away. If it’s not treated, the condition can damage the tissues in your penis and cause irreversible erectile dysfunction (ED).

If you have an erection that lasts longer than 4 hours, go to the nearest emergency room or call 911.

What can I do to make Viagra work faster?

Viagra may work faster if you take it on an empty stomach. However, if Viagra is taken with food, especially with a high-fat meal, it will take longer to start working. And in this case, it could even be less effective for you.

How long will Viagra stay in my system?

After taking a dose of Viagra, the drug’s level in your body will gradually decrease over a period of a few hours. You’ll have low levels of the drug in your body after about 4 hours. (And at this point, the drug won’t be working any longer.) But it can actually take about 24 hours for Viagra to be completely removed from your body.

Viagra is approved to treat erectile dysfunction (ED) in men. With ED, you have trouble getting and keeping an erection that’s firm enough to allow you to have sex.

What causes an erection?

When you’re sexually aroused, either through sexual thoughts or touch, your brain sends messages to your penis. These messages cause certain chemicals to be released in your penis.

One of these chemicals, called cyclic GMP, relaxes and widens certain blood vessels in your penis. Cyclic GMP also relaxes the muscles around the erectile tissue in your penis that’s called the corpus cavernosum. These actions allow blood to flow into the corpus cavernosum, which causes your penis to get hard and become erect.

What happens with ED?

ED can occur if you have certain problems that affect your body’s ability to have an erection. The condition can result from problems with messages being sent from your brain. ED can also result from problems with blood flow into your penis.

What does Viagra do for ED?

Viagra works to treat ED by helping you have and maintain an erection. The drug does this by improving blood flow into your penis when you’re sexually aroused.

Viagra is a type of drug called a phosphodiesterase type 5 (PDE5) inhibitor. It works by inhibiting (blocking) the action of an enzyme called PDE5. (An enzyme is a protein that helps chemical reactions to happen inside your body.)

Normally, an erection goes away when PDE5 breaks down the cyclic GMP in your penis. But Viagra blocks the action of PDE5, so it allows cyclic GMP to keep working for a longer period of time than usual. This action improves blood flow to your penis and helps you to have and keep an erection.

Does Viagra increase a man’s sex drive?

No, Viagra doesn’t directly increase your sex drive. And it doesn’t make you sexually aroused. However, some men find that if Viagra works to treat their erectile problem, it also increases their sexual confidence. And this may lead to an increased sex drive.

How can I tell if Viagra’s not working?

Viagra may not work for everyone, and it may not work every time you take it.

If you’re sexually aroused, Viagra should work to help you have or keep an erection within 30 minutes to 2 hours. But if you don’t get an erection within 4 hours after taking a dose, Viagra didn’t work for you this time.

If the drug doesn’t work for you, you shouldn’t take another dose until at least 24 hours later. And talk with your doctor if you feel Viagra isn’t helping to treat your ED. They may recommend that you try a different medication for your ED.

How can I get Viagra to work?

It’s important to remember that Viagra only works if you’re already sexually aroused. Arousal may involve having sexual thoughts, looking at sexual images, masturbating, or engaging in foreplay.

But if you feel anxious, nervous, depressed, or stressed, your body may not respond well to sexual stimulation. If this is the case, try to relax, make yourself comfortable, and take your time. In addition, it’s best to avoid drinking a lot of alcohol. This is because consuming large amounts of alcohol can make it more difficult for you to get an erection.

If you’re having trouble getting an erection, even while using Viagra, talk with your doctor.

Is Viagra a blood thinner?

No, Viagra isn’t a blood thinner. Instead, it belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. (A class of drugs describes a group of medications that work in a similar way.) Viagra works by inhibiting (blocking) the action of a certain enzyme in your body.

Since Viagra has been released onto the market, there have been a few reports of bleeding in people who’ve taken the drug. However, there’s no evidence that Viagra caused these bleeding problems.

It’s not known if Viagra is safe for use by people with a bleeding problem. If you have any bleeding problems, talk with your doctor about whether Viagra is safe for you.

Here are answers to some frequently asked questions about Viagra. And for answers to questions related to Viagra’s dosage, see the section “Viagra dosage” above.

Can Viagra make sex last longer?

No, studies haven’t shown that Viagra makes sex last longer. However, the drug can help you to get and keep an erection. And studies have shown that Viagra can increase satisfaction from sex.

Does Viagra increase the size of a man’s penis?

No, Viagra doesn’t increase the size of a man’s penis. In fact, to date, there aren’t any known ways to permanently increase the size of a man’s penis.

Viagra helps you get an erection if you’re sexually aroused. This may temporarily increase the size of your penis, until the erection goes away. But Viagra doesn’t permanently increase the size of your penis.

Is Viagra safe to use?

Yes, Viagra is generally considered safe to use if:

  • it’s been prescribed by a doctor who knows your medical history
  • you’re taking the drug as directed

Viagra’s safety has been shown in several clinical studies. The drug does have a few serious side effects, but these rarely occur. For more information about the side effects of Viagra, see the section “Viagra side effects” above.

However, Viagra may not be safe to use if you have certain medical conditions, including heart disease. And it’s not safe to use Viagra if you’re taking certain other medications, such as nitrates. (Nitrates are sometimes used to treat chest pain that’s related to heart problems.) This is why you should only take Viagra if it’s been prescribed by a doctor who knows your medical history.

For more information about conditions that may make it unsafe for you to take Viagra , see the “Viagra precautions” section below. And for more information about taking other medications with Viagra, see the “Viagra interactions” section below.

Can you take Viagra if you have high blood pressure?

That depends on how high your blood pressure is.

For example, if you have high blood pressure that’s not controlled, your heart may not be healthy enough for sexual activity. (With uncontrolled high blood pressure, your blood pressure is greater than 170/110 mmHg.) If this is the case, talk with your doctor about whether Viagra is safe for you.

However, if you have high blood pressure that’s controlled with medication and you also don’t have a heart condition, it’s usually fine to take Viagra. Just be aware that taking the drug could cause your blood pressure to be lowered.

Low blood pressure from Viagra usually isn’t a problem for most people. But if you’re taking a type of blood pressure drug called an alpha-blocker, taking Viagra might cause certain side effects. These side effects can include dizziness, lightheadedness, or even fainting. For more information about using Viagra with alpha-blockers, see the “Viagra interactions” section below.

If you have high blood pressure that’s controlled with medication, your doctor may prescribe a dose of Viagra for you that’s lower than the typical dose.

Before starting Viagra, talk with your doctor about any blood pressure problems you have.

Does Viagra work the first time you use it?

Yes, for most people, Viagra works the first time it’s used. But for other people, it may take a few times of trying the drug to get the desired effect. Keep in mind that you shouldn’t take Viagra more than once every 24 hours.

If Viagra doesn’t seem to work for you, talk with your doctor. They may increase your dose of the drug or recommend that you try a different medication.

Does Viagra help me keep an erection after ejaculation?

It might. But even if your erection goes away after you’ve ejaculated, Viagra can help you to get another erection for up to 4 hours after you’ve taken a dose.

Can I take Viagra by snorting it?

No, you shouldn’t snort Viagra. The safety and effectiveness of taking Viagra through your nose hasn’t been tested. This drug is only approved to be taken by mouth.

Does Viagra prevent ejaculation?

No, Viagra doesn’t stop you from ejaculating.

Can I take Viagra after I’ve had my prostate removed?

Yes, you can if your doctor recommends it.

However, Viagra may be less effective in treating erectile dysfunction (ED) in men who’ve had their prostate removed than it is in men who haven’t.

Across several clinical studies, Viagra was effective in 43% of men who’d had this surgery. And a placebo (treatment with no active drug) was effective in 15% of men who’d had the surgery. In comparison, in studies of men with ED due to:

  • complications from diabetes, 57% had improved erections with Viagra. This is compared with 10% of men who took a placebo.
  • spinal cord injury, 83% had improved erections with Viagra. This is compared with 12% of men who took a placebo.

If you have questions about using Viagra after you’ve had your prostate removed, talk with your doctor.

Does Viagra treat ED that’s related to diabetes?

Yes, it can be used for this purpose. In fact, one study found that Viagra was effective in 57% of men with erectile dysfunction (ED) that was thought to be related to diabetes.

Does Viagra help with premature ejaculation?

Yes, it could. In several studies, Viagra has been looked at as a possible treatment for premature ejaculation (PE). (With PE, you ejaculate before you want to. And typically, you’ll ejaculate within 1 minute of penetration when you’re having sex.)

Some studies found that Viagra can help men with PE to delay ejaculation longer than they could without treatment. However, other studies didn’t show that Viagra had a significant effect in treating PE. More research is needed to know for sure whether or not Viagra is effective for treating PE.

Keep in mind that Viagra isn’t approved in the United States to treat PE. And it’s not recommended in current PE treatment guidelines from the American Urological Association. However, Viagra is recommended in similar guidelines from the European Association of Urology.

If you’re interested in taking Viagra to treat PE, talk with your doctor.

What’s the youngest age for which Viagra is safe to use?

Viagra is approved for use in males ages 18 years and older. You shouldn’t take Viagra if you’re younger than 18 years. This is because the safety and effectiveness of Viagra haven’t been studied in people of this age group.

The manufacturer of Viagra doesn’t give any specific warnings about drinking alcohol while using this drug. But in general, it’s best to avoid drinking lots of alcohol with the medication.

This is because certain side effects of Viagra may be worsened by alcohol. This includes such side effects as headaches, flushing, and dizziness. And drinking lots of alcohol can also make it more difficult to get an erection, which is what you’d be using Viagra to do.

If you drink alcohol, talk with your doctor about how much is safe for you to drink while you’re taking Viagra.

Viagra can interact with several other medications. Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Viagra and other medications

Below are lists of medications that can interact with Viagra. These lists don’t contain all the drugs that may interact with Viagra.

Before taking Viagra, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Viagra and other ED medications

You shouldn’t take Viagra with any other medications for erectile dysfunction (ED). This includes prescription medications, such as:

  • tadalafil (Cialis)
  • avanafil (Stendra)
  • vardenafil (Levitra, Staxyn)
  • alprostadil (Muse, Caverject, Caverject Impulse, Edex)

It also includes natural or over-the-counter ED treatments, such as l-arginine and yohimbine.

Taking Viagra with other ED medications increases your risk of certain side effects, such as low blood pressure and priapism.*

If you’re using Viagra, don’t use any other medications for ED without talking with your doctor.

* Priapism is a long-lasting and sometimes painful erection that doesn’t go away. It’s a medical emergency because it can damage the tissues in your penis and lead to permanent ED.

Viagra and nitrates

You shouldn’t take Viagra with nitrate drugs. This includes certain prescription drugs, such as nitroglycerin, used to treat angina (a type of chest pain). It also includes certain illicit drugs called poppers, such as amyl nitrate.

Taking Viagra with nitrates can cause a dangerous drop in your blood pressure that can lead to heart attack or stroke.

Examples of nitrate drugs that should not be taken with Viagra include:

  • nitroglycerin (Nitromist, Nitro-Dur, Nitrolingual Pumpspray, Gonitro, others)
  • isosorbide mononitrate (Monoket)
  • isosorbide dinitrate (Dilatrate SR, Isordil)
  • glyceryl trinitrate
  • amyl nitrate
  • alkyl nitrate
  • butyl nitrate

Viagra and drugs for pulmonary arterial hypertension

You shouldn’t take Viagra if you’re taking the pulmonary arterial hypertension (PAH)* drugs listed below. Taking Viagra with these medications can cause your blood pressure to drop too low.

Examples of drugs used to treat PAH that should not be taken with Viagra include:

* With PAH, you have high blood pressure in the artery between your heart and lungs.

Viagra and blood pressure drugs

Viagra can sometimes cause low blood pressure. Taking Viagra with drugs used to treat high blood pressure can cause your blood pressure to drop even lower.

Examples of drugs used to treat high blood pressure include:

If you take a drug for high blood pressure, your doctor might prescribe a dose of Viagra for you that’s lower than the typical dose.

Viagra and alpha-blockers

If you’re taking a type of blood pressure drug called an alpha-blocker, the extra drop in blood pressure from Viagra could make you feel dizzy or lightheaded. It could even make you faint. If you’re taking an alpha-blocker, your doctor will recommend a starting dose of 25 mg of Viagra, which is lower than the usual starting dose.

Examples of alpha-blocker drugs used for high blood pressure include:

If you take one of the drugs listed above, tell your doctor if you feel dizzy or lightheaded, or faint after taking Viagra.

Viagra and illicit drugs

You shouldn’t take Viagra with illicit drugs called poppers. Poppers contain nitrate drugs such as amyl nitrate, alkyl nitrate, and butyl nitrate. Taking Viagra with poppers can cause a dangerous drop in your blood pressure that can lead to heart attack or stroke.

Viagra hasn’t been tested for use with illicit drugs other than poppers. But it’s possible that taking Viagra with certain other illicit drugs could also have dangerous effects on your heart and blood pressure.

Examples of illicit drugs that could have dangerous effects if taken with Viagra include:

If you’re thinking of using illicit drugs with Viagra, talk with your doctor about whether this is safe for you to do.

Viagra and certain BPH drugs

Viagra can sometimes cause low blood pressure. Certain drugs used to treat benign prostatic hyperplasia (BPH)* can also cause low blood pressure. These drugs are called alpha-blockers.

Taking Viagra with alpha-blockers can cause your blood pressure to drop even lower. This could make you feel dizzy or lightheaded, or even cause you to faint.

Examples of alpha-blockers that are used to treat BPH include:

If you’re taking an alpha-blocker, your doctor will recommend a starting dose of 25 mg of Viagra, which is lower than the usual starting dose. And if you take one of the drugs listed above, tell your doctor if you feel very dizzy, lightheaded, or faint after taking Viagra.

* With BPH, you have an enlarged prostate.

Viagra and Adderall

Viagra hasn’t been tested for use with Adderall, so it’s not known what effects the drugs would have if taken together. But that doesn’t mean there wouldn’t be an interaction.

Adderall, which contains amphetamine salts, is approved to treat attention deficit hyperactivity disorder (ADHD). Adderall has stimulant effects in your body, and it could cause serious heart-related side effects.

Viagra, on the other hand, may cause low blood pressure. So it’s possible that taking it with Adderall could have dangerous effects on your heart or blood pressure.

If you take Adderall, ask your doctor if it’s safe for you to take Viagra as well.

Viagra and Xanax

Viagra hasn’t been tested for use with Xanax, so it’s not known what effects the drugs would have if taken together. But that doesn’t mean there wouldn’t be an interaction.

Xanax, which is a benzodiazepine, contains the active drug alprazolam. Xanax can sometimes cause low blood pressure, dizziness, and fainting. Viagra may also lower your blood pressure. So it’s possible that taking it with Xanax could have dangerous effects on your heart or blood pressure.

If you take Xanax, ask your doctor if it’s safe for you to take Viagra as well.

Viagra and antidepressants

It’s usually fine to take Viagra with antidepressants. It’s important to note that erectile dysfunction (ED) is a common side effect of certain antidepressants. This is particularly true for selective serotonin reuptake inhibitors (SSRIs), such as sertraline (Zoloft). And Viagra is sometimes prescribed to treat ED that’s caused by antidepressants.

If you have questions about whether you can take Viagra with an antidepressant, talk with your doctor.

Viagra and certain antimicrobials

Taking Viagra with certain antimicrobials (drugs used to treat infection) can slow the breakdown of Viagra in your body. This can cause Viagra to build up inside your body, which may increase your risk of side effects from the drug.

Examples of antimicrobial drugs that can increase the risk of side effects from Viagra include:

  • certain antibiotics, such as:
    • clarithromycin
    • erythromycin
    • telithromycin (Ketek)
  • certain antifungals, such as:
    • ketoconazole (Nizoral)
    • itraconazole (Sporanox)
    • posaconazole (Noxafil)
    • voriconazole (Vfend)
  • certain antivirals used for HIV, such as:
    • atazanavir (Reyataz)
    • cobicistat (Tybost)
    • ritonavir (Norvir)
    • indinavir sulfate (Crixivan)
    • nelfinavir mesylate (Viracept)
    • saquinavir mesylate (Invirase)

If you take one of the drugs listed above, your doctor will recommend you take a starting dose of 25 mg for Viagra. (This is lower than the typical starting dose of Viagra.) And if you take ritonavir, you shouldn’t take more than one 25-mg dose of Viagra within a 48-hour period.

Viagra and herbs and supplements

There aren’t any herbs or supplements that have been specifically reported to interact with Viagra. However, you should still check with your doctor or pharmacist before using any of these products while taking Viagra.

Viagra and foods

There aren’t any foods that have been specifically reported to interact with Viagra. If you have any questions about eating certain foods with Viagra, talk with your doctor.

Viagra and grapefruit

Grapefruit juice can affect the levels of some medications in your body. But there’s not much evidence to show that the fruit or its juice can affect Viagra levels.

One small study was done in 2002. It showed that drinking grapefruit juice with Viagra slightly increased people’s blood level of the drug. This could possibly increase the risk of certain side effects such as headaches, flushing, or dizziness. But these side effects weren’t specifically reported in the study.

If you want to drink grapefruit juice or eat grapefruit while you’re taking Viagra, talk with your doctor. They can recommend whether this is safe for you to do. If you do have increased side effects with this combination, try avoiding grapefruit while you’re taking Viagra.

Viagra comes as tablets that are taken by mouth. You should take Viagra according to your doctor’s or healthcare provider’s instructions.

When to take

For most people, it’s recommended that you take Viagra as needed, about 1 hour before you plan to have sex. But Viagra can actually be taken anywhere from 30 minutes to 4 hours before sexual activity.

It’s important to remember that you shouldn’t take the medication more than once a day.

Taking Viagra with food

You can take Viagra either with or without food. But if you take it with a meal, the drug may take about an hour longer than usual to start working. This is especially the case if you eat a high-fat meal, such as a cheeseburger with fries.

You don’t need to wait to take Viagra if you’ve recently eaten a meal. Just be aware that it might take a bit longer for the drug to work.

It’s also important to remember that if Viagra gives you indigestion, taking the drug with food may help to reduce this side effect.

Can Viagra be crushed, split, or chewed?

The safety and effectiveness of Viagra tablets that are crushed, split, or chewed haven’t been tested. And Viagra tablets are meant to be swallowed whole. It’s not known if crushing or chewing the tablets will make them work any differently than usual.

If you have trouble swallowing Viagra tablets, you might find it easier to swallow the tablet with different drinks, such as water, juice, or milk. Or talk with your doctor or pharmacist about how else you can take the drug.

If you want to crush, split, or chew Viagra tablets, ask your doctor or pharmacist if this is safe to do.

The Food and Drug Administration (FDA) approves prescription drugs such as Viagra to treat certain conditions. Viagra may also be used off-label for other conditions. Off-label use is when a drug that’s approved to treat one condition is used to treat a different condition.

Viagra for ED

Viagra is FDA-approved to treat erectile dysfunction (ED) in males ages 18 years and older. With ED, you’re not able to get and keep an erection that’s firm enough to have sex. This condition is a common problem that’s experienced by many men.

ED can be caused by several different factors. These include psychological or emotional problems, such as:

But ED may also be caused by physical problems, such as:

Viagra increases blood flow to your penis, which helps you have and maintain an erection. However, the drug itself doesn’t give you an erection. It only works if you’re sexually aroused.

Effectiveness for ED

In several clinical studies, Viagra was effective in treating ED. In these studies, men who used the drug had an improved ability to have and keep erections that allowed for successful sex.

Across the studies, between 43% and 83% of men who took Viagra had improved erections. (These success rates varied depending on the cause of their ED and the dosage of Viagra being used.) In comparison, improved erections occurred in 10% to 24% of men who took a placebo (no active drug).

Effectiveness of Viagra at different doses

Some studies looked at the effect of different doses of Viagra. These studies, which involved 1,797 men, lasted up to 6 months. Improved erections were reported in:

  • 63% of men who took 25 mg of Viagra
  • 74% of men who took 50 mg of Viagra
  • 82% of men who took 100 mg of Viagra
  • 24% of men who took a placebo (no active drug)

Effectiveness of Viagra for ED with different causes

Other studies have looked at the effect of Viagra in men whose ED had different causes.

For example, one study specifically looked at men with ED that was related to complications of diabetes. Improved erections were reported in:

  • 57% of men who took Viagra
  • 10% of men who took a placebo

One study only involved men with ED that resulted from a spinal cord injury. Improved erections were reported in:

  • 83% of men who took Viagra
  • 12% of men who took a placebo

Also, using information from multiple studies, researchers looked at how well Viagra worked in men with ED that developed after they’d had surgery to remove their prostate gland. Improved erections were reported in:

  • 43% of men who took Viagra
  • 15% of men who took a placebo

In addition, men whose ED had psychological causes were specifically looked at as part of one study. Improved erections were reported in:

  • 84% of men who took Viagra
  • 26% of men who took a placebo

Off-label use for Viagra

In addition to the use described above, Viagra may be used off-label. Off-label drug use is when a drug that’s approved for one condition is given for a different condition that’s not approved. Below is an example of an off-label use for Viagra.

Viagra for Raynaud’s disease

Viagra isn’t approved to treat Raynaud’s disease, but sometimes it’s used off-label for this condition.

With Raynaud’s disease, the blood vessels in your hands and feet spasm and temporarily become narrowed. These narrowed blood vessels restrict blood supply to your fingers or toes. This can cause your fingers and toes to look white and feel cold, painful, or numb. Episodes of spasm can be triggered by cold temperatures or emotional stress.

Viagra works to treat Raynaud’s disease by relaxing and widening certain blood vessels in your body. One review of studies found that PDE5 inhibitors, including Viagra, can improve Raynaud’s disease. (PDE5 inhibitors describes a certain class of drugs. Medications in the same class of drugs work in a similar way inside your body.)

In fact, in the studies, these drugs reduced the number of Raynaud’s disease episodes people had. And the drugs also decreased how long the episodes lasted.

If you have questions about using Viagra for Raynaud’s disease, talk with your doctor.

Viagra and children

Viagra is only approved for use in adult males with ED. It hasn’t been studied in people younger than 18 years of age.

Viagra is approved to treat erectile dysfunction (ED) in men. But you may have questions about whether Viagra can be used in women. Or you may be wondering if there’s a drug similar to Viagra that can help women with sexual dysfunction. Below, we provide answers to these questions.

Can women take Viagra?

No, Viagra isn’t approved for use in women. And there isn’t enough evidence to show that Viagra works for treating sexual problems in women.

One review of studies showed that current research has conflicting results on how Viagra affects women. For example, in women with female sexual arousal disorder, the review showed the following findings:

  • In one study, some women who’d gone through menopause were given Viagra. These women had improved arousal, vaginal lubrication, and orgasm when they took the drug.
  • In another study, both women who’d gone through menopause and those who hadn’t were given Viagra. These women reported no significant positive effects from taking the drug.

In men, Viagra improves blood flow to their penis by blocking the action of a chemical called PDE5. This chemical is also found in the vagina and the clitoris of women. So in theory, if a woman takes Viagra, it could increase blood flow to her genitals.

But in reality, there’s less PDE5 in a female’s genitals than there is in a male’s penis. This could explain why Viagra has less of a physical effect in women than it does in men.

And keep in mind that sexual problems in women often have a lot to do with reduced sexual desire and arousal. Viagra is unlikely to address these issues.

Is there a “female Viagra”?

While Viagra isn’t approved for use in women, a drug called Addyi is approved for use in certain women. Some people refer to Addyi as “female Viagra.” However, Addyi doesn’t work like Viagra does. Below, we describe the condition Addyi is approved to treat and how the drug works.

If you have questions about using Addyi, talk with your doctor.

What is Addyi?

Addyi is a brand-name prescription drug that’s approved to treat hypoactive sexual desire disorder (HDSS). It’s prescribed for women who haven’t yet gone through menopause. Addyi contains the active drug flibanserin. It’s not known for sure how Addyi works to treat HDSS.

What is HDSS and how does Addyi work to treat it?

With HDSS, you have very low sexual desire that’s troublesome for you. The condition can have various physical or psychological causes.

Unlike Viagra, which improves blood flow to male genitals, Addyi doesn’t work by improving blood flow to female genitals. Instead, Addyi affects the activity of certain neurotransmitters that are involved in sexual desire and arousal. (Neurotransmitters are chemicals found in your brain.)

The neurotransmitters affected by Addyi include dopamine, noradrenaline, and serotonin. But it’s not known for sure how the drug’s action affects sexual function.

How well does Addyi work?

For some women with HDSS, Addyi can improve sexual desire and increase the number of sexually satisfying events. But the drug hasn’t been found to be very effective.

For example, in clinical studies, treatment with Addyi was compared with that of a placebo (no active drug). The number of women whose HDSS was “much improved” or “very much improved” was only about 10% higher in women who took Addyi compared with women who took the placebo.

And keep in mind that it can take up to 8 weeks for Addyi to start working to treat HDSS.

When you get Viagra from the pharmacy, the pharmacist will add an expiration date to the label on the bottle. This date is typically 1 year from the date they dispensed the medication.

The expiration date helps guarantee that the medication is effective during this time. The current stance of the Food and Drug Administration (FDA) is to avoid using expired medications. If you have unused medication that has gone past the expiration date, talk to your pharmacist about whether you might still be able to use it.

Storage

How long a medication remains good (also called shelf-life) can depend on many factors. These factors include how and where you store the medication.

Viagra tablets should be stored at room temperature between 68 o F and 77°F (20 o C and 25°C). It should be kept in a tightly sealed container away from light. Avoid storing this medication in areas where it could get damp or wet, such as in bathrooms.

Disposal

If you no longer need to take Viagra and have leftover medication, it’s important to dispose of it safely. This helps prevent others, including children and pets, from taking the drug by accident. It also helps keep the drug from harming the environment.

This article provides several useful tips on medication disposal. You can also ask your pharmacist for information on how to dispose of your medication.

Using more than the recommended dosage of Viagra can lead to serious side effects. Do not use more Viagra than your doctor recommends.

What to do if you think you’ve taken too much Viagra

If you think you’ve taken too much of this drug, call your doctor. You can also call the American Association of Poison Control Centers at 800-222-1222 or use their online tool. But if your symptoms are severe, call 911 or go to the nearest emergency room right away.

Before taking Viagra, talk with your doctor about your health history. Viagra may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • History of allergic reaction to Viagra or sildenafil. Don’t take Viagra if you’ve ever had an allergic reaction to Viagra or sildenafil (the active drug in Viagra). If you’re not sure of your medication allergies, talk with your doctor.
  • Heart problems or stroke. If you have a heart problem, or you’ve had a heart problem or stroke in the past, talk with your doctor about whether Viagra is safe for you. Heart problems include conditions such as angina (a type of chest pain), heart attack, heart failure, and aortic stenosis (narrowing of the main artery that leaves your heart). Heart problems also include irregular heartbeat patterns, such as atrial fibrillation (A-fib). Taking Viagra and having sexual activity may not be recommended if your doctor thinks that doing so will put too much strain on your heart. If you have a heart problem and you take Viagra, stop sexual activity if you get any chest pain, dizziness, or nausea. And don’t take nitrate medications to treat chest pain while you’re using Viagra. If you have any heart-related symptoms, call 911 if the symptoms feel life threatening or if you think you’re having a medical emergency. And be sure to see your doctor before taking Viagra again.
  • High blood pressure. Viagra can lower your blood pressure. If you’re taking medication to treat high blood pressure, taking Viagra could cause your blood pressure to drop even further. In some cases, this could make you feel dizzy or lightheaded, or cause you to faint. And if you have high blood pressure that’s not controlled (measuring higher than 170/110 mmHg), your heart may not be healthy enough for sex. If you have high blood pressure, talk with your doctor about whether Viagra is right for you. If you’re able to take Viagra, your doctor will usually prescribe a dosage for you that’s lower than the typical dosage.
  • Low blood pressure. Viagra can lower your blood pressure. If you already have low blood pressure, taking Viagra can make it drop even further. This could make you feel dizzy or lightheaded, or cause you to faint. If your blood pressure is below 90/50 mmHg, talk with your doctor about whether Viagra is right for you. If you are able to take Viagra, your doctor will usually prescribe a dosage for you that’s lower than the typical dosage.
  • Physical abnormalities affecting your penis. If you have problems with your penis, such as bending, scarring, or Peyronie’s disease, it might not be safe for you to take Viagra. (With Peyronie’s disease, you have an abnormal curvature of your penis.) Rarely, Viagra may cause priapism (a long-lasting and sometimes painful erection). If you have a physical problem affecting your penis, getting priapism with Viagra could cause further damage to your penis. Talk with your doctor about whether Viagra is right for you.
  • Blood cell problems. If you have a blood cell problem, such as sickle cell anemia, multiple myeloma, or leukemia, Viagra may not be safe for you. This is because having these conditions could increase your risk of priapism (a long-lasting and sometimes painful erection) with Viagra. Talk with your doctor about whether Viagra is right for you.
  • Non-arteritic anterior ischemic optic neuropathy (NAION). NAION is an eye condition that causes damage to your optic nerve. This damage causes a sudden decrease or loss of vision in one or both eyes. Rarely, Viagra may cause this problem. If you’ve already had this eye condition in the past, you could have a higher risk of developing it with Viagra. Talk with your doctor about whether Viagra is right for you.
  • Hereditary retinitis pigmentosa. This condition, which affects your eye, is passed down in families. Viagra hasn’t been studied in people with hereditary retinitis pigmentosa. Talk with your doctor about any eye problems you may have. They’ll recommend whether Viagra is safe for you.
  • Severe kidney problems. If you have certain kidney problems and your kidneys don’t work well,Viagra can build up in your body. This can increase your risk of side effects from the drug. If you have severe kidney problems, your doctor will prescribe a dosage of Viagra for you that’s lower than the typical dosage.
  • Liver problems. If you have certain liver problems and your liver doesn’t work well, Viagra can build up in your body. This can increase your risk of side effects from the drug. If you have liver problems, your doctor will prescribe a dosage of Viagra for you that’s lower than the typical dosage.
  • Bleeding problems. There have been a few reports of bleeding in people who’ve taken Viagra since this drug was approved and released onto the market. However, there’s no evidence that Viagra caused these problems. It’s not known if Viagra is safe for people with a bleeding problem. If you have any bleeding problems, talk with your doctor about whether Viagra is right for you.
  • Peptic ulcer. It’s not known whether Viagra is safe for people who have a peptic ulcer. If you have or have had an ulcer in the past, talk with your doctor about whether Viagra is suitable for you.
  • Pregnancy. Viagra isn’t approved for use in women. For more information, please see the “Viagra and pregnancy” section below.
  • Breastfeeding. Viagra isn’t approved for use in women. For more information, please see the “Viagra and breastfeeding” section below.

Note: For more information about the potential negative effects of Viagra, see the “Viagra side effects” section above.

As with all medications, the cost of Viagra can vary. To find current prices for Viagra in your area, check out GoodRx.com.

The cost you find on GoodRx.com is what you may pay without insurance. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

Your insurance plan may require you to get prior authorization before approving coverage for Viagra. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the request and let you and your doctor know if your plan will cover Viagra.

If you’re not sure if you’ll need to get prior authorization for Viagra, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Viagra, or if you need help understanding your insurance coverage, help is available.

Pfizer, the manufacturer of Viagra, offers a program that can help lower the cost of Viagra. For more information and to find out if you’re eligible for support, call 855-842-4722 or visit the program website.

Generic version

Viagra is available in generic form called sildenafil. A generic drug is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. And generics tend to cost less than brand-name drugs.

To find out how the cost of sildenafil compares to the cost of Viagra, visit GoodRx.com. Again, the cost you find on GoodRx.com is what you may pay without insurance. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

If your doctor has prescribed Viagra and you’re interested in using sildenafil instead, talk with your doctor. They may have a preference for one version or the other. You’ll also need to check your insurance plan, as it may only cover one or the other.

Viagra isn’t approved for use in women. And it hasn’t been studied in pregnant women. It’s not known whether this drug is safe to take during pregnancy.

In animal studies, Viagra didn’t cause fetal harm when given to pregnant females. But animal studies don’t always predict what will happen in humans.

If you have questions about the safety of Viagra use during pregnancy, talk with your doctor.

It’s not known if Viagra is safe to take during pregnancy. (But keep in mind that the drug isn’t approved for use in women.)

If you’re sexually active and you or your partner can become pregnant, talk with your doctor about whether you’ll need to use birth control while you’re taking Viagra.

Viagra isn’t approved for use in women. And it hasn’t been studied in women who are breastfeeding. Viagra may pass into breast milk, but it’s not known if this could affect a nursing child.

If you have questions about the safety of using Viagra while breastfeeding, talk with your doctor.

The following information is provided for clinicians and other healthcare professionals.

Indication

Viagra is approved to treat erectile dysfunction (ED) in males ages 18 years and older.

Administration

Viagra is taken orally. It should be taken between 30 minutes and 4 hours before planned sexual activity.

Mechanism of action

Viagra contains sildenafil citrate, an inhibitor of phosphodiesterase type 5 (PDE5). Viagra enhances the action of cyclic GMP, which is released in the penis in response to sexual stimulation. Cyclic GMP dilates smooth muscle in the penile tissue. It also increases blood to flow into the corpus cavernosum, causing an erection.

Viagra blocks PDE5 from breaking down cyclic GMP, thereby improving the ability to achieve and maintain an erection in response to sexual stimulation.

Pharmacokinetics and metabolism

Sildenafil has an average bioavailability of 41% (ranges from 25% to 63%) after oral administration of Viagra tablets.

When taken on an empty stomach, the time to reach peak plasma concentration (Tmax) is approximately 30 to 120 minutes. The median Tmax is 60 minutes. Taking Viagra with a high-fat meal delays Tmax by about 60 minutes. It also reduces the maximum plasma concentration (Cmax) by an average of 29%.

Sildenafil is primarily metabolized by hepatic CYP3A4, to a metabolite with similar activity to sildenafil. Sildenafil and its active metabolite have a terminal half-life of approximately 4 hours.

Approximately 80% of the dose is excreted in feces, and approximately 13% is excreted in urine.

Reduced clearance of sildenafil is seen in people ages 65 years and over, and in those with hepatic impairment or severe renal impairment.

Contraindications

Viagra is contraindicated in people with a known allergy to sildenafil, or any of the inactive ingredients in Viagra.

Viagra is also contraindicated for use in combination with:

  • nitrate drugs in any form, such as:
    • nitroglycerin (Nitromist, Nitro-Dur, Nitrolingual Pumpspray, Gonitro, others)
    • isosorbide mononitrate (Monoket)
  • guanylate cyclase stimulators, such as riociguat (Adempas)

Storage

Store Viagra at room temperature between 68 o F and 77°F (20 o C and 25°C).

Disclaimer: Medical News Today 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 other 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.