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Stendra (Avanafil) 101: How it Works, Side Effects & More

Kristin Hall, FNP

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 10/06/2020

Stendra® (avanafil) is a PDE5 inhibitor medication used to treat erectile dysfunction (ED). Like Viagra® (sildenafil), Cialis® (tadalafil) and Levitra® (vardenafil), Stendra makes it easier to get and maintain an erection if you suffer from erectile dysfunction.

A relatively new ED medication, Stendra was developed throughout the 2000s and approved in April 2012 by the FDA. This makes it far newer than ED drugs like Viagra, which have been in use by men since the 1990s to help treat ED problems.

Because of its newer formula, Avanafil, the active ingredient in Stendra, has fewer side effects than the active ingredients in older ED medications like Viagra, Cialis and Levitra.

Below, we’ve explained what Stendra is and how it’s used to treat erectile dysfunction. We’ve also looked at some of the key advantages Stendra offers compared to older ED medications, from its slightly longer-than-average half-life to its lower risk of causing certain side effects.

What is Stendra (Avanafil)?

Stendra is an erectile dysfunction medication. More specifically, it’s a PDE5 inhibitor. It works by inhibiting the cGMP-specific phosphodiesterase type 5 enzyme (more simply, PDE5), which can regulate blood flow to the erectile tissue of your penis.

When you’re sexually aroused, your body increases the rate of blood flow to your penis. Avanafil, the active ingredient in Stendra, triggers the release of nitric oxide in the corpus cavernosum tissue of the penis, which results in the smooth muscle in the corpus cavernosum relaxing, thereby allowing more blood into it, helping you get and stay hard.

Like other ED medications, Stendra won’t cause you to randomly get erections. Instead, it only makes it easier to get an erection if you’re already sexually aroused.

Stendra comes in tablet form in a variety of doses. The most common doses are 50mg, 100mg and 200mg, all of which are designed for use 15 minutes to 30 minutes before engaging in sexual activity, depending on your dosage. A normal dose of Stendra lasts for up to six hours after you take the medication.

As a second-generation ED medication, Stendra has several differences from older drugs such as Viagra, including a reduced risk of causing certain side effects. We’ve covered these in more detail in the section below.

How Does Stendra Differ From Other ED Medications?

Stendra was developed throughout the 2000s and in 2012 gained approval by the FDA. This makes it the newest erectile dysfunction medication on the market. In comparison, Viagra was approved by the FDA in 1998, followed in 2003 by both Cialis and Levitra.

This means that Stendra is more than a decade newer than the original, first generation of ED treatments. There are several key differences between Stendra and the first generation drugs used to treat ED:

  • Stendra typically works faster. Most of the first-generation ED medications take 30 to 60 minutes to start working. In some cases, such as if you’ve eaten a large meal, it can take longer than 60 minutes for Viagra to become fully effective.
    The 100mg and 200mg doses of Stendra may take only 15 minutes to start working, meaning they can be taken closer to the time you have sex. Even the lower 50mg dose of Stendra can be taken 30 minutes before sex.

  • Stendra works for longer than some ED medications. How long does Stendra last? Although it doesn’t last as long as medications like Cialis, Stendra has a slightly longer half-life than Viagra, allowing it to provide relief from ED for up to six hours at a time. Our Stendra vs. Cialis guide goes into more detail on the differences between these two treatments and explains which option is likely the best for you.

  • Stendra has fewer side effects. Although Stendra isn’t completely free of side effects, it has fewer side effects than the first-generation ED treatments. Specifically, it’s less likely to cause side effects related to impaired vision and low blood pressure.
    This is because Stendra is designed to specifically target the PDE5 enzyme, without as much of an effect on other PDE enzymes such as PDE1, PDE3, PDE6 and PDE11.

  • Stendra is less affected by food. First-generation ED treatments often take longer to start working — or are less effective — if you’ve eaten a large meal or foods that are high in fat before using them.
    Stendra is less affected by your food intake than other ED medications, meaning you’ll get the full effects from the medication even if you take it after eating a large amount of food.

  • Stendra is safe to use with alcohol. Compared to first-generation ED treatments such as Viagra (sildenafil, generic Viagra), Stendra is safer and more effective at treating erectile dysfunction if you have consumed alcohol.
    Although you’ll still need to limit your alcohol consumption if you plan to use Stendra, it’s okay to have up to three servings of alcohol without significantly increasing your risk of experiencing side effects.

  • For some people, Stendra is more effective. Because of the way Stendra works, it’s often more effective than older ED medications like Viagra. Specifically, statistics show that Stendra is more effective at treating ED in some difficult-to-treat patients.

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How Effective is Stendra (Avanafil)?

Although Stendra is a relatively new medication, there are already several studies that show it’s highly effective at treating erectile dysfunction.

In a clinical review of avanafil (the active ingredient in Stendra) from 2014, five studies involving more than 2,200 men were reviewed to assess the medication’s results.

The researchers found that avanafil is highly effective at improving International Index of Erectile Function-Erectile Function (IIEF-EF — a score used to assess erection problems). The men who received the medication showed improvements at all doses, from 50mg to 200mg.

As you might expect, avanafil was most effective at the highest 200mg dose. Unlike many other ED medications, which are more likely to cause side effects at a higher dose, the largest dose of avanafil did not appear to significantly increase the risk of the men experiencing side effects.

In a study from 2012, researchers found that avanafil was an “effective and well-tolerated” as a treatment for erectile dysfunction. The men involved in the study who received avanafil showed a significant improvement in IIEF-EFD at a dose of either 100mg or 200mg.

Finally, in clinical trials for avanafil, researchers stated that the drug "demonstrated statistically significant improvement in all three primary efficacy variables” related to erectile function. This study involved more than 600 men, ranging in age from 23 to 88 years old.

In short, avanafil works very well as a treatment for erectile dysfunction, with studies finding that it produces significant, measurable improvements in erection quality for men of all ages who are affected by ED.

How to Use Stendra (Avanafil)

Like other ED medications, Stendra is very easy to use. Simply take the Stendra tablet 15 minutes to 30 minutes before you plan to have sex.

If you’re prescribed a lower dose of Stendra, such as the 50mg tablet, it’s recommended to use the medication at least 30 minutes before sexual activity. This allows your body enough time to fully absorb the medication’s active ingredient.

It’s okay to take Stendra on an empty stomach or with food. Stendra is safe to use after drinking alcohol, although you should limit your alcohol consumption to a maximum of three servings (for example, three glasses of wine or beer) to avoid increasing your risk of side effects.

You can safely use Stendra a maximum of once per day. Depending on how well the medication works for you, your healthcare provider might recommend adjusting your dose to ensure you receive the full benefits from the medication.

Stendra is a prescription medication, meaning you’ll need to speak with your healthcare provider and receive a prescription before you can purchase and use it. They will provide an appropriate dosage based on your symptoms and other factors (such as your age and general health).

If you're concerned about the price of Stendra, you can read our blog on how much Stendra costs.

Stendra can interact with some medications, particularly nitrates used to treat hypertension and other cardiovascular conditions. We’ve explained this in more detail below, along with other side effects you may experience while using Stendra.

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Side Effects of Stendra (Avanafil)

Stendra is a safe, effective medication that only has few side effects, none of which are very common.

For example, headaches, the most common side effect of Stendra, only affect five percent to 10 percent of men who use the medication.  

Because Stendra works the same as other PDE5 inhibitors, such as Viagra and Cialis, its side effects are similar to these medications. Common side effects of Stendra include:

  • Headache. This is by far the most common side effect of Stendra. In FDA trials, 5.1 percent of men who used Stendra at 50mg (the lowest effective dose) experienced headaches. At the highest 200mg dose, headaches were reported by 10.5 percent of users. Headaches from Stendra are caused by the effects of the medication on blood flow. Like other Stendra side effects, they’re usually mild and short-lived, with discomfort fading as the medication exits your system.

  • Flushing. Facial flushing is another common side effect of Stendra, affecting 3.2 percent to 4.3 percent of men depending on the dose used. Like headaches, flushing from Stendra is a result of the medication’s effects on blood flow and fades away over the course of several hours.

  • Nasal congestion. Between 1.8 percent and 2.9 percent of men who use Stendra report some degree of nasal congestion after taking the medication. Like other side effects, this is caused by dilation of blood vessels and only lasts as long as the medication is in your system.

  • Nasopharyngitis (cold symptoms). Between 0.9 percent and 3.4 percent of men who use Stendra experience cold-like symptoms, like a stuffy nose, after using the medication. Like other side effects, this is temporary and resolves itself over the course of several hours.

  • Back pain. Mild, temporary back pain affects 1.1 percent to 3.2 percent of men who use Stendra. As with the other side effects listed above, this is a common side effect of all medications used to treat ED. As a second-generation ED medication, Stendra is less likely to cause side effects than older drugs, such as Viagra. For example:

  • Headaches (the most common side effect of both drugs) are reported by 10.5 percent of men who use the highest dose of Stendra, versus 28 percent of men who use the highest dose of Viagra.

  • Flushing is reported by 4.3 percent of men who use the highest dose of Stendra, versus 18 percent of men who use the highest dose of Viagra.

Stendra’s more selective effects on the PDE5 enzyme also mean it doesn’t cause certain side effects that are common in older medications.

For example, up to 11 percent of men who use Viagra at the highest 100mg dose report vision problems, versus less than one percent of Stendra users.

Like other ED medications, Stendra can cause a mild reduction in your blood pressure levels while it’s active in your body.

If you use nitrates to treat hypertension or other cardiovascular health conditions, you should not use Stendra.

These medications can interact with Stendra and cause you to experience a significant drop in blood pressure that can lead to fainting, heart attack or stroke.

Stendra, as well as similar PDE5 inhibitors, can also interact with certain alpha-blockers and CYP3A4 inhibitors.

Because of this, it’s important to inform your healthcare provider about all medications you currently use when you’re discussing Stendra as an ED treatment option.

Overall, Stendra is a safe and effective treatment for erectile dysfunction. While side effects do occur in a small percentage of men who use the medication, they’re usually mild and occur less often than with older, first-generation ED treatments.

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Learn More About Treating Erectile Dysfunction

As the newest FDA-approved erectile dysfunction medication, Stendra is a great option if you suffer from ED and want to use a medication that’s newer and less likely to cause side effects than older drugs such as Viagra (sildenafil), Cialis (tadalafil) or Levitra (vardenafil).

You can learn more about how Stendra works, as well as other medications used to treat ED, in our guide to what to expect from erectile dysfunction medication.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.