A Complete Guide to Stendra® (Avanafil) Side Effects

Kristin Hall, FNP

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 2/1/2022

Erectile dysfunction, or ED, is one of the most common sexual performance issues for men, with an estimated 30 million men affected in the United States alone.

Treatments for erectile dysfunction have been available for several decades. In 1998, the Food and Drug Administration approved Viagra®, making it the first oral medication available to treat erectile dysfunction.

Other medications, such as Cialis® and Levitra®, were approved in the early 2000s, giving men with ED a larger choice of treatment options.

Stendra®, which contains the active ingredient avanafil, is the newest ED medication to appear on the market. It was approved by the FDA in 2012 and offers numerous advantages over older medications for ED, including a reduced risk of causing certain side effects.

Although Stendra is less likely to cause side effects than other ED medications, it’s still possible to experience side effects while using Stendra.

Below, we’ve listed the side effects of Stendra, with study data on how frequently each problem can occur. 

We’ve also explained what you can do to deal with Stendra side effects when they occur, from talking to your healthcare provider to making changes to the way you use your medication.

How Does Stendra Work?

Stendra contains the active ingredient avanafil. It belongs to a class of medications referred to as PDE5 inhibitors, which work by dilating the blood vessels that supply blood to certain areas of your body, including the erectile tissue of your penis.

Erections rely on both sexual stimulation and healthy blood flow. Many conditions that cause or contribute to ED, such as hypertension (high blood pressure) and heart disease, can affect the ability for blood to properly flow through your arteries to your penis.

By improving blood flow to your penis, Stendra can make it easier for you to get and sustain an erection before and during sexual activity.

Stendra is available in the United States as a prescription medication. We offer Stendra online, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate.

The Most Common Side Effects of Stendra (Avanafil)

As a newer PDE5 inhibitor, avanafil is highly selective, meaning its effects are more focused on the tissue of the penis and less so on other parts of the body.

This means that certain side effects of ED drugs are less common with Stendra than with older erectile dysfunction medications.

According to FDA data, the common side effects of Stendra occur at about one third the rate of the equivalent side effects of Viagra.

If you often get side effects from Viagra, Cialis or Levitra®, Stendra might be a good alternative ED treatment for you.

Although it’s less likely to cause side effects than other ED medications, Stendra can and often does still cause adverse effects. We’ve listed these below, along with information on how each side effect may affect you if you’re prescribed Stendra to treat erectile dysfunction.


Headaches are the most common side effect reported by men who use Stendra. In trials carried out as part of Stendra’s approval process, 5.1 percent of men reported headaches after taking a 50mg dose of Stendra (the lowest effective dose).

At the recommended initial dose of 100mg, 6.9 percent of men experienced headaches. At the highest 200mg dose of Stendra, headaches were reported by 10.5 percent of men.

It’s worth noting that headaches were also reported as a side effect by 1.7 percent of men who received a non-therapeutic placebo.

Like with other side effects, headaches are generally less common with Stendra than with other ED medications. For example, up to 15 percent of men who used Cialis and 28 percent of men who used Viagra in clinical trials reported headaches as a side effect.

Headaches from Stendra may occur as a result of the effects of the medication on blood flow in your body. If you develop a headache after taking Stendra, it should eventually pass on its own as the medication exits your body. 

Using over-the-counter pain relief with Stendra may reduce the severity of headaches. If you’re affected by persistent or severe headaches from Stendra, talk to your healthcare provider about adjusting your dosage. 

You can also try implementing the techniques in our complete guide to treating headaches from ED medication.

Viagra online

Genuine Viagra® makes it possible

Facial Flushing

Flushing is a common side effect of all ED medications, including Stendra. It affects 3.2 percent of men who use Stendra at the lowest 50mg dose. At higher doses of 100mg and 200mg, about four percent of men develop this side effect.

Older, less selective ED medications are more likely to produce facial flushing than Stendra. For example, between 10 and 19 percent of men who use Viagra to treat ED experience some level of facial flushing.

Facial flushing is caused by the effect of PDE5 inhibitors such as Stendra on blood vessels. As your blood vessels widen, your skin may take on a red color and feel warmer than usual.

Like other Stendra side effects, facial flushing typically becomes less severe as the total amount of medication in your bloodstream declines. 

Nasal Congestion

Stendra may cause the smooth muscle within your sinuses to expand, causing nasal congestion and the feeling of a stuffy, partially blocked nose. This side effect occurs in between 1.8 and 2.9 percent of men who use Stendra to treat erectile dysfunction. 

In comparison, up to nine percent of men who take Viagra have some level of nasal congestion as a side effect.

Nasal congestion from Stendra is sometimes accompanied by other cold symptoms, such as a mild swelling in your sinuses. These effects may gradually become less severe as the amount of Stendra in your body declines. 

Back Pain

Bain pain is a known side effect of ED medications, including Stendra. This issue is reported by a small percentage of men who use Stendra. Interestingly, research suggests that it affects men who use Stendra at a mild 50mg dose more frequently than those who take higher doses. 

In clinical trials of Stendra, 3.2 percent of men prescribed the medication at 50mg reported back pain, compared to just 1.1 percent of men who used the strongest 200mg dosage. 

Back pain is generally more common in men who use older ED medications. For example, up to four percent of men who took Viagra in trials and six percent of men who used Cialis noted back pain as a side effect.  

This side effect may become less severe over the course of several hours as avanafil, the active ingredient in Stendra, gradually exits your body.

If you have severe or persistent back pain after using Stendra, it’s best to inform your healthcare provider. They may suggest adjusting your dosage or using additional medication to reduce any pain and/or discomfort. 

Less Common Side Effects of Stendra (Avanafil)

Stendra can also cause several less common side effects. These side effects affected less than one percent of men who used Stendra as an as-needed ED treatment in clinical trials. In some cases, a clear causal relationship between these effects and Stendra was not established. 

As with the common side effects listed above, many of these side effects are relatively mild and pass on their own as the medication exits your body: 

  • Fatigue

  • Angina

  • Heart palpitations

  • Gastritis

  • Gastroesophageal reflux disease (GERD)

  • Hypoglycemia

  • Hyperglycemia

  • Oropharyngeal pain

  • Stomach discomfort and/or vomiting

  • Depression

  • Insomnia

  • Somnolence (drowsiness)

  • Musculoskeletal pain

  • Pain in the extremities

  • Vertigo

  • Respiratory symptoms, such as cough and wheezing

  • Pruritus (itchy skin)

  • Balanitis (inflammation of the head of the penis)

  • Hematuria (blood in urine)

  • Nephrolithiasis (kidney stones)

  • Frequent daytime urination

  • Urinary tract infection (UTI)

These side effects occurred in less than one percent of men who used Stendra for ED in clinical trials. If you develop any of these side effects while using Stendra, it’s important to inform your healthcare provider. 

Due to its more specific action on PDE5, Stendra is less likely to cause vision ocular side effects than older medications such as Viagra.

In several FDA studies involving more than 1,000 participants, only one man prescribed Stendra reported vision-related issues. 

ED treatments, delivered

Generic for Viagra (sildenafil)

The more affordable FDA-approved medication that treats Erectile Dysfunction at a quarter of the cost. 🙌

Generic for Cialis (tadalafil)

Affordable and helps get the job done. Generic Cialis helps you get and maintain your erections through a simple, daily dosage.


The OG Little Blue Pill that made its name as the first prescription Erectile Dysfunction treatment.


Cialis helps you get and keep stronger erections with a daily or as-needed pill.

Serious Side Effects of Stendra (Avanafil)

Serious side effects from all ED medications are uncommon. Due to its more selective action in the body, Stendra has an even lower risk of causing serious side effects than other medications for treating ED.

Despite this, in rare cases, it’s possible for Stendra to cause more serious side effects. Severe potential side effects of Stendra include: 

  • Priapism. This is a type of painful erection that can last for several hours. It’s a potential side effect of all PDE5 inhibitors that can cause permanent damage to the tissue of your penis if left untreated.You may have a higher risk of priapism if you have angulation, Peyronie’s disease or any other anatomical penis deformation. Conditions such as leukemia, sickle cell anemia or multiple myeloma may also increase your risk of developing priapism.If you develop a painful, prolonged erection after using Stendra (for example, an erection that lasts for several hours), you should ​​seek medical help immediately.

  • Vision issues. A small percentage of men who use Stendra develop vision issues, such as changes in color vision and loss of vision. These side effects are less common with Stendra than with older ED medications. Vision issues may be a sign of nonarteritic anterior ischemic optic neuropathy (NAION) -- a potentially serious eye problem.If you develop sudden vision loss or other vision-related side effects after using Stendra to treat ED, it’s important to seek medical attention as soon as possible.

  • Loss of hearing. Although rare, Stendra may cause hearing issues, including tinnitus or sudden hearing loss. Seek medical advice if you notice any significant changes in your hearing after using Stendra or other ED medication. 

Stendra (Avanafil) Drug Interactions and Safety

For most men, Stendra is a safe and effective medication when used as directed. However, like other prescription medications, it’s important to take caution before using Stendra with any other medications or substances.

Stendra can interact with some medications used to treat cardiovascular health conditions such as angina and hypertension (high blood pressure).

For example, Stendra and other PDE5 inhibitors should not be used with nitrates. When used together, Stendra and nitrates can cause a sudden, significant drop in blood pressure that may lead to dizziness, fainting, heart attack or stroke.

Recreational drugs that contain nitrates, such as amyl nitrate and butyl nitrate “poppers” used for sexual enhancement, are also unsafe when used with Stendra.

Stendra can also interact with other medications used to treat high blood pressure and/or heart disease, including alpha blockers.

Other medications that can interact with Stendra include:

  • Certain oral antifungal medications, including ketoconazole and itraconazole.

  • Some antibiotics, including erythromycin, clarithromycin and telithromycin.

  • HIV medications called protease inhibitors, including ritonavir, indinavir, atazanavir and saquinavir.

  • Other medications used to treat erectile dysfunction.

Some of these medications are CYP3A4 inhibitors that may affect the absorption and effects of Stendra in the body. 

To avoid interactions, it’s important to inform your healthcare provider about all medications you currently use or have recently used before discussing Stendra.

It’s also important to inform your healthcare provider if you:

  • Have experienced a cardiovascular event such as heart attack or stroke.

  • Have been diagnosed with a heart condition, such as angina (chest pain caused by poor blood flow), irregular heartbeat or heart failure.

  • Have recently had heart surgery or any other type of surgical procedure.

  • Have uncontrolled hypotension (low blood pressure) or hypertension (high blood pressure).

  • Have a condition that affects your blood cells, such as multiple myeloma, leukemia or sickle cell anemia.

  • Have a deformed penis shape or injury to your penis.

  • Have the eye disease retinitis pigmentosa.

  • Have liver, kidney or bleeding problems.

  • Have any other medical conditions.

As a vasodilator, Stendra can increase the blood-pressure-lowering effects of alcohol. It’s best to either avoid alcohol while using Stendra, or limit your alcohol consumption to no more than three units (for example, three glasses of wine).

Make sure to use Stendra exactly as prescribed by your healthcare provider. If you have safety concerns or questions about using Stendra or other types of medication to treat ED, feel free to reach out to your healthcare provider for advice and assistance. 

Stendra Dosage

Stendra comes in tablet form in several strengths. Your healthcare provider may prescribe you Stendra in one of three dosages:

  • Stendra 100mg. This is the starting dose of Stendra for most patients. Your healthcare provider will likely prescribe this dose of Stendra if you have mild to moderate ED, or if you have not experienced any issues with other erectile dysfunction treatments. Research shows that more than 73 percent of men with ED are able to achieve vaginal penetration using this dose of Stendra.

  • Stendra 50mg. Your healthcare provider may reduce your dosage of Stendra if you get side effects from the 100mg dosage, or if you have mild erectile dysfunction that doesn’t require such a strong dose of medication. Research shows that more than 64 percent of men with ED are able to achieve vaginal penetration using this dose of Stendra.

  • Stendra 200mg. This is the highest dose of Stendra. You may be prescribed Stendra at this dose if you have moderate to severe erectile dysfunction that doesn’t improve with a lower dose of medication. Research shows that more than 77 percent of men with ED are able to achieve vaginal penetration using this dose of Stendra.

Stendra should be taken as needed approximately 30 minutes before sexual activity, either with or without a meal. Regardless of dosage, Stendra should not be taken no more than one time per day.

If you’re prescribed Stendra and feel that it’s not fully effective, or think that you may get better results from a reduced dosage, talk to your healthcare provider. Do not adjust your dosage of Stendra without first consulting your healthcare provider.

Sildenafil citrate

Get hard for 95% cheaper than Viagra

Learn More About Treating Erectile Dysfunction

Stendra is the newest medication used in the treatment of erectile dysfunction. It’s fast to work and has fewer side effects than older ED medications, making it worth considering if you’d like to enjoy convenient and easy relief from ED. 

We offer Stendra and other medications for ED online, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate. 

Want to learn more before you get started? You can find out more about how Stendra works in our Stendra 101 guide, or learn more about dealing with ED in our complete guide to the most common erectile dysfunction treatments and drugs

8 Sources

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

  1. Definition & Facts for Erectile Dysfunction. (2017, July). Retrieved from
  2. VIAGRA® (sildenafil citrate) tablets, for oral use. (2014, March). Retrieved from
  3. STENDRA™ (avanafil) tablets, for oral use. (2012, April). Retrieved from
  4. Dhaliwal, A. & Gupta, M. (2021, June 25). PDE5 Inhibitors. StatPearls. Retrieved from
  5. Symptoms & Causes of Erectile Dysfunction. (2017, July). Retrieved from
  6. Burke, R.M. & Evans, J.D. (2012). Avanafil for treatment of erectile dysfunction: review of its potential. Vascular Health and Risk Management. 8, 517–523. Retrieved from
  7. CIALIS (tadalafil) tablets, for oral use. (2011, October). Retrieved from
  8. Kim, J.N., et al. (2019, December). Influence of Alcohol on Phosphodiesterase 5 inhibitors Use in Middle- to Old-Aged Men: A Comparative Study of Adverse Events. Sexual Medicine. 7 (4), 425–432. Retrieved from

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.