Stendra (Avanafil) - Oral

What Is Stendra?

Stendra (avanafil) is an oral medication used to treat erectile dysfunction (ED). It belongs to the drug class called phosphodiesterase-5 enzyme (PDE-5) inhibitors.

Avanafil does not directly cause a penis erection when you take it but works during sexual arousal. It affects the release of nitric oxide and an enzyme called cyclic guanosine monophosphate (cGMP) in the body. cGMP relaxes the muscle, causing an increase in blood flow to the penis.

Another enzyme called phosphodiesterase-5 enzyme breaks down cGMP. However, Stendra blocks the PDE-5 enzyme from breaking down cGMP, leading to a more prolonged erection. 

Stendra is available as tablets only with a prescription.

Drug Facts

Generic Name: Avanafil

Brand Name(s): Stendra

Administration Route(s): Oral

Drug Availability: Prescription

Therapeutic Classification: Erectile dysfunction

Available Generically: No

Controlled Substance: No

Active Ingredient: Avanafil

Dosage Form(s): Tablet

What Is Stendra Used For?

The Food and Drug Administration (FDA) approved Stendra to treat erectile dysfunction (ED). It is usually taken as needed, as directed by the healthcare provider.

Stendra (Avanafil) Drug Information - Illustration by Dennis Madamba

Verywell / Dennis Madamba

How to Take Stendra

Stendra is not a routine or daily drug. Only use this pill as needed and as advised by your healthcare provider.

To use Stendra for ED, take it 15 to 30 minutes before sex for the 100 milligram (mg) dose and 30 minutes before sex for the 50 mg dose. Your healthcare provider may increase your dose to a maximum of 200 mg if needed. Do not take it more than once a day.

Grapefruit juice may affect your medicine. It can raise the levels of this drug in your system, which can cause:


Store Stendra at room temperature (68–77 degrees Fahrenheit) away from light. You may store this medicine at mildly hot temperatures (86 degrees) during trips. Keep it in a dry place and away from children and pets. Do not keep this medication in your bathroom.

Make sure to properly get rid of unused and expired drugs. Do not throw them down the drain, toilet, or sink. Ask your pharmacist about the best ways to dispose of your pills. Check out drug take-back programs in your area.

How Long Does Stendra Take to Work?

Taking this drug without food causes it to peak between 30 minutes and 45 minutes in your system. However, with a high-fat meal, it takes between 60 and 90 minutes to reach its peak.

What Are the Side Effects of Stendra?

This is not a complete list of side effects, and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at or 800-FDA-1088.

Common Side Effects

In some people, Stendra may have little or no adverse effects. Contact your healthcare provider right away if your side effects do not go away or become bothersome. The most common side effect of Stendra include:

Severe Side Effects

Tell your medical provider right away if you have any serious adverse effects. If you have a medical emergency or if your symptoms are life-threatening, dial 911. Severe side effects of Stendra include:

  • Chest pain or pressure
  • Trouble speaking 
  • Drooping on one side of the face
  • Change in balance
  • Throwing up
  • Passing out
  • Fast or abnormal heartbeat
  • Terrible dizziness 
  • Very upset stomach  
  • Weakness on one side of the body
  • Blurred, change, or loss of eyesight
  • Painful erection (hard penis) or an erection that lasts for longer than four hours
  • Ringing in the ears, change in hearing, or hearing loss

Report Side Effects

Stendra may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much of Stendra Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For treatment of erectile dysfunction (as needed):
      • Adults—At first, 100 milligrams (mg) as a single dose, no more than once a day, taken 15 minutes before sexual intercourse. Your doctor may adjust your dose if needed. However, the dose is usually not more than 200 mg once a day.
      • Children—Use is not recommended.


Avoid taking Stendra and nitrates together. If there is a life-threatening emergency that requires you to take a nitrate, take the nitrate at least 12 hours after Stendra.

Taking Stendra with alpha-blockers or certain drugs that reduce your blood pressure may cause an excessive drop in your blood pressure. This can result in dizziness or fainting. Your healthcare provider may modify your dose based on how your body reacts to Stendra.

Missed Dose

Only take this medication as needed. Unless your provider tells you to, do not take more than once every 24 hours.

Overdose: What Happens If I Take Too Much Stendra?

Standard supportive treatment may be necessary in cases of an overdose. Contact your healthcare provider if you think you've taken too much Stendra.

What Happens If I Overdose on Stendra?

If you think you or someone else may have overdosed on Stendra, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Stendra, call 911 immediately.


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It is important that you tell all of your doctors that you take avanafil. If you need emergency medical care for a heart problem, it is important that your doctor knows when you last took avanafil.

Do not use this medicine if you are also using riociguat (Adempas®), vericiguat (Verquvo®), or a nitrate medicine, often used to treat angina (chest pain) or high blood pressure. Nitrate medicines include nitroglycerin, isosorbide, Imdur®, Nitro-Bid®, Nitro-Dur®, Nitrol® Ointment, Nitrolingual® Spray, Nitrostat®, and Transderm Nitro®. Some illegal ("street") drugs called "poppers" (eg, amyl nitrate, butyl nitrate, or nitrite) also contain nitrates. If you need to use a nitrate medicine for emergency, take it at least 12 hours after your last dose of avanafil.

Do not take this medicine if you are also using other PDE5 inhibitors, including sildenafil (Viagra®), tadalafil (Cialis®), or vardenafil (Levitra®). If you take too much avanafil or take it together with these medicines, the chance for side effects will be higher.

It is important to tell your doctor about any heart problems you have now or may have had in the past. This medicine can cause serious side effects in patients with heart problems.

If you experience a prolonged or painful erection for 4 hours or more, contact your doctor immediately. This condition may require prompt medical treatment to prevent serious and permanent damage to your penis.

If you experience sudden loss of vision in one or both eyes, contact your doctor immediately.

Check with your doctor right away if you have a sudden decrease in hearing or loss of hearing, which may be accompanied by dizziness and ringing in the ears.

If you already use medicine for high blood pressure (hypertension), avanafil could make your blood pressure go too low. Call your doctor right away if you have blurred vision, confusion, dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly, sweating, or unusual tiredness or weakness.

Do not drink excessive amounts of alcohol (eg, more than 3 glasses of wine or 3 shots of whiskey) when taking avanafil. When taken in excess, alcohol can increase your chances of getting a headache or getting dizzy, increase your heart rate, or lower your blood pressure.

This medicine does not protect you against sexually transmitted diseases (including HIV or AIDS). Use protective measures and ask your doctor if you have any questions about this.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn't Take Stendra?

Do not take Stendra if you are:

  • Hypersensitive to avanafil or any part of its formulation
  • Taking any form of nitrates (either regularly or sparingly)
  • Taking drugs in a class called guanylate cyclase stimulators (e.g., riociguat)

What Other Medications Interact With Stendra?

Certain drugs may affect how well Stendra works. Additionally, taking Stendra with medications such as alpha-blockers, blood pressure–lowering drugs, and substantial amounts of alcohol can lead to low blood pressure.

Avoid taking the following medications with Stendra:

What Medications Are Similar?

Medications similar to Stendra that can also treat ED include:

This list includes drugs also prescribed to treat ED. It is not a list of medicines recommended to take with Stendra. Do not take these drugs together unless your healthcare provider tells you to. If you have any problems, talk to your provider.

Frequently Asked Questions

  • What is Stendra used to treat?

    The Food and Drug Administration approved Stendra to treat erectile dysfunction.

  • What is the common side effect of Stendra?

    Some common side effects of Stendra include:

    • Flushing
    • Back pain
    • Runny or stuffy nose
    • Sore throat
    • Headache
  • What should I do if I miss a dose of Stendra?

    This drug is only taken as needed. Do not take more than once every 24 hours.

How Can I Stay Healthy While Taking Stendra?

Stendra works well when taken correctly. Before you start using this medication, be open and honest with your healthcare provider about your medical history. 

Tell your provider if:

Being transparent and open with your provider helps them select the most appropriate drugs for you. ED can be a manageable condition. Call your medical provider if you have any concerns while on this medicine.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Stendra label.

  2. Huang SA, Lie JD. Phosphodiesterase-5 (PDE5) inhibitors In the management of erectile dysfunction. P T. 2013;38(7):407-419.

By Queen Buyalos, PharmD
Queen Buyalos is a pharmacist and freelance medical writer. She takes pride in advocating for cancer prevention, overall health, and mental health education. Queen enjoys counseling and educating patients about drug therapy and translating complex ideas into simple language.