Avanafil (Stendra): the fast-acting ED medicine explained

By the Medsmingle Team · Updated 13 November 2026

This is a prescription medicine. Only take it if it has been prescribed for you after a medical assessment, and follow your doctor’s and pharmacist’s instructions.

Avanafil, sold as Stendra, is the newest PDE5 inhibitor approved in the US for erectile dysfunction. Some prescribed doses may be taken as little as 15 minutes before sex; timing and response vary.

Timing

• Can work from about 15 minutes (for the higher doses), typically within 30 minutes
• Lasts up to about 6 hours
• Can be taken with or without food

Dosing

The usual starting dose is 100 mg about 15 to 30 minutes before sex, adjusted to 50 mg or 200 mg, no more than once a day. Lower doses are used with some interacting medicines.

Side effects

• Headache
• Flushing
• Stuffy nose
• Back pain (less common)

Some studies suggest fewer visual side effects than older ED medicines, but large comparison trials are limited.

Who must avoid it or needs specialist assessment

• Anyone taking nitrates (nitroglycerin, isosorbide mononitrate or dinitrate) or recreational “poppers” (amyl nitrite): the combination can cause a dangerous drop in blood pressure
• Anyone taking riociguat (Adempas) for pulmonary hypertension
• Do not use if your clinician says sexual activity is unsafe. A recent heart attack or stroke requires individual specialist assessment.
• Very low blood pressure, severe liver disease or inherited eye conditions require assessment before treatment; suitability differs between medicines.

Get emergency help (call 911) if you have

• Chest pain, fainting or severe dizziness during or after sex: tell the medical team you took an ED medicine, including the exact medicine and when you last took it
• An erection lasting more than 4 hours (priapism), which can permanently damage the penis
• Sudden loss or decrease of vision in one or both eyes
• Sudden decrease or loss of hearing, with or without ringing or dizziness
• Swelling of the face, lips or throat, or trouble breathing

Interactions

• Do not take with strong CYP3A4 inhibitors (ketoconazole, ritonavir, clarithromycin)
• Lower maximum dose with moderate inhibitors such as erythromycin, fluconazole or verapamil
• Alpha-blockers: start low under medical advice
• Don’t combine with other ED medicines

Frequently asked questions

Is avanafil generic?

Availability of generics varies by country. Ask a licensed pharmacist to verify current availability and the approval status of the exact product you are offered.

Is it stronger than Viagra?

Not stronger; it may work faster for some men.

For questions about a prescription or symptoms, speak with your own doctor or pharmacist. For website enquiries, contact our team.

General information only. It isn’t a substitute for advice from your doctor or pharmacist.

Source

MedlinePlus: avanafil.