Avanafil (Stendra): uses, side effects, interactions, and more

Reviewed by Chimene Richa, MD, 

Written by Michael Martin 

Reviewed by Chimene Richa, MD, 

Written by Michael Martin 

last updated: Dec 17, 2021

5 min read

Most people are familiar with Viagra, the “little blue pill,” but have you heard of Stendra? It’s one of the newer drugs to help treat erectile dysfunction (ED). Read on to learn about its uses, side effects, and more. 

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What is Stendra?

Stendra is the brand name for avanafil, a medication used to treat erectile dysfunction. It's part of a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors, which also includes:  

Avanafil and other PDE5 inhibitors work by suppressing an enzyme called PDE5, which is basically an erection's off switch. When these drugs inhibit PDE5, the blood vessels in the penis stay open, and your penis stays hard (Padda, 2021). This can prolong an erection or make it easier to get an erection when you're aroused.

Stendra may be the fastest-acting PDE5 inhibitor. While sildenafil can take up to 30 minutes to work, you can take avanafil just 15 minutes before having sex. Keep in mind, though, that it's not a magic boner pill—you have to be aroused for avanafil to work.

Viagra Important Safety Information: Read more about serious warnings and safety info.

Cialis Important Safety Information: Read more about serious warnings and safety info.

Stendra uses

Stendra is FDA-approved to treat erectile dysfunction (ED). 

ED is when you can't get or maintain an erection sufficient for satisfying sex. People with ED may also notice a lack of morning erections. This condition is very common—approximately 30–50 million men in the U.S. have experienced ED (Sooriyamoorthy, 2021). ED can happen at any age, but it becomes more common as men get older. By the time a man is in his 40s, he has about a 40% chance of having experienced ED at some point. This likelihood goes up by about 10% for each successive decade of life (Ferrini, 2017).

But just because it can happen with age, ED is not considered a "natural" part of aging. It may be the first sign of a more severe underlying medical condition, such as (Sooriyamoorthy, 2021): 

  • Heart disease—One of the most common causes of erectile dysfunction in men over 50 is atherosclerosis or hardening of the arteries. The build-up of plaque in the arteries causes the blood vessels to become stiff and narrow, reducing blood flow throughout the body, including the penis, and causing erection problems. Heart disease can also lead to heart attacks and strokes. 

  • High blood pressure (hypertension)—Having high blood pressure makes blood pump through the blood vessels more forcefully than it should, damaging and narrowing the vessel walls. This decreases blood flow and reduces a person's ability to achieve and maintain an erection.

  • Diabetes—High blood sugar, or diabetes, can damage the blood vessel walls, which impedes blood flow throughout the body, including the penis.

  • Anxiety and depressionDepression, anxiety, relationship problems, and performance insecurity can all contribute to ED.

Stendra side effects

For the most part, PDE5 inhibitors are considered relatively safe and have similar side effects. Common side effects of avanafil include headache, flushing, nasal congestion, and back pain (Padda, 2021). Seek medical advice if those are severe or don't go away.

Serious side effects of avanafil can also occur. Call your healthcare professional or seek emergency medical help if you experience any of the following symptoms (DailyMed, 2021):

  • A prolonged erection lasting more than four hours (priapism)

  • Sudden vision loss 

  • Sudden hearing loss 

  • Ringing in the ears (tinnitus)

  • Dizziness

  • Itching

  • Rash

  • Swollen eyelids

Stendra dosage

Avanafil is available in dosages of 50 mg, 100 mg, and 200 mg. The typical starting dose is 100 mg. Your healthcare provider will determine which dose is right for you (DailyMed, 2021).

Because it is so fast-acting, you can take Stendra 15 minutes before sexual activity. Remember that you still need sexual stimulation to get an erection, even with the drug.  

You can take Stendra with or without food. Studies suggest that taking avanafil with a high-fat meal can make the drug take longer to work (Evans, 2015). 

Stendra drug interactions

Be sure to talk to your healthcare provider before starting avanafil. Discuss your medical history and any over-the-counter or prescription drugs you may be taking to avoid potential drug interactions. 

If you are taking nitrates (such as nitroglycerin, isosorbide, nitroprusside), which are typically used to treat chest pain or heart conditions, you cannot take PDE5 inhibitors—the combination can cause a potentially fatal drop in blood pressure. Similarly, never take PDE5 inhibitors with the club drug, poppers (amyl nitrites), as this combination is also dangerous (DailyMed, 2021)

Do not take Stendra if you also use guanylate cyclase (GC) stimulators, like riociguat (brand name Adempas). The combination increases your risk of low blood pressure.

Certain medications affect the way your liver processes drugs like Stendra. Examples include ketoconazole, ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, and telithromycin. If you take any of these medications, you should not take avanafil because of the increased risk of side effects (DailyMed, 2021).

People with high blood pressure (hypertension) may take medications to lower their blood pressure (antihypertensives). Alpha-blockers are one class of antihypertensive drugs sometimes used. Taking Stendra with alpha-blockers, like doxazosin and terazosin, can cause your blood pressure to drop to dangerously low levels. Tamsulosin (brand name Flomax) is an alpha-blocker used to treat prostate issues (like benign prostatic hyperplasia). You should not take it with avanafil because of the risk of low blood pressure (DailyMed, 2021).

The side effects you experience on PDE5 inhibitors may depend on the dosage you take. If you experience side effects while taking ED medication, talk with your healthcare provider. They may adjust your dosage or choose a different ED medication that is right for you.


Stendra warnings

Before starting Stendra, or any other erectile dysfunction treatment, talk to your healthcare professional to rule out underlying medical issues that may be contributing to your ED. Some people should use extra caution when taking avanafil because of an increased risk of side effects. 

You should not take avanafil if you're not healthy enough for sexual activity—your healthcare provider can help answer any questions about this. 

Like other PDE5 inhibitors, Stendra can cause low blood pressure. If you already have heart problems (like a history of heart disease or heart failure, low blood pressure, or other medical issues, have a discussion with your healthcare professional about whether you should use Stendra (DailyMed, 2021).

People with certain eye problems, like non-arteritic ischemic optic neuropathy (NAION), should talk to a healthcare professional before using avanafil.

Don’t take Stendra if you have had an allergic reaction to avanafil or any of the inactive ingredients in Stendra.

Which ED treatment is best for me?

Deciding what ED medication is best for you depends on several factors, including:

  • Price/insurance coverage 

  • Interactions with other medicines you're taking

  • Dosages

  • How quickly it works and how long it lasts

A healthcare provider can help you decide which ED medication is your best bet.

However, you can also ask your provider about treatments for erectile dysfunction other than medications like Stendra and Viagra. Other treatments for ED include (Sooriyamoorthy, 2021): 

  • Drugs injected into the penis (alprostadil, BiMix, TriMix)

  • Lifestyle changes (likes eating a healthier diet, exercising regularly, avoiding tobacco, drinking less alcohol, and losing weight)

  • Surgery to resolve issues contributing to the development of ED, such as Peyronie's disease

  • Devices such as cock rings and penis pumps

  • Counseling to resolve anxiety, depression, or other


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

December 17, 2021

Written by

Michael Martin

Fact checked by

Chimene Richa, MD

About the medical reviewer

Dr. Richa is a board-certified Ophthalmologist and medical writer for Ro.