Medically Reviewed on 1/20/2023

Generic Name: avanafil

Brand Name: Stendra

Drug Class: Phosphodiesterase-5 Enzyme Inhibitors

What is avanafil, and what is it used for?

Avanafil is an oral drug that is used for treating impotence (the inability to attain or maintain a penile erection), also known as erectile dysfunction (ED). It is in a class of drugs called phosphodiesterase inhibitors, which also includes tadalafil (Cialis), sildenafil (Viagra), and vardenafil (Levitra).

Erection of the penis is caused by the filling of the penis with blood. Filling occurs because the blood vessels that bring blood to the penis increase in size and deliver more blood to the penis, and, at the same time, the blood vessels that take blood away from the penis decrease in size and remove less blood from the penis. Sexual stimulation that leads to an erection causes the production and release of nitric oxide in the penis. The nitric oxide causes an enzyme, guanylate cyclase, to produce cyclic guanosine monophosphate (cGMP).

It is cGMP that is primarily responsible for increasing and decreasing the size of blood vessels carrying blood to and from the penis, respectively, and causing an erection. When the cGMP is destroyed by another enzyme, phosphodiesterase-5, the blood vessels return to their normal size, blood leaves the penis, and the erection ends. Avanafil prevents phosphodiesterase-5 from destroying cGMP so that cGMP stays around longer. The persistence of cGMP leads to a more prolonged engorgement of the penis with blood.

Avanafil was approved by the FDA in April 2012.

What are the side effects of avanafil?

The most common side effects of avanafil are:

Avanafil also may cause low blood pressure, blurred vision and changes in color vision, and abnormal ejaculation. Avanafil may cause prolonged erections or priapism (painful erections lasting more than 6 hours). Patients should seek immediate medical help if they experience an erection lasting more than 4 hours.

Use of avanafil, especially in patients with pre-existing heart disease, may cause

Rare cases of sudden loss of hearing have been reported with phosphodiesterase inhibitors such as avanafil, sometimes associated with ringing in the ears and dizziness. If changes in hearing occur, patients should stop their avanafil and seek immediate medical attention. Phosphodiesterase-5 inhibitors have been associated rarely with non-arteritic anterior ischemic optic neuropathy (NAION), a condition which causes decreased vision and may lead to blindness.


Erectile Dysfunction (ED) Causes and Treatment See Slideshow

What is the dosage for avanafil?

  • For most individuals, the recommended starting dose of avanafil is 100 mg per day taken about 30 minutes before sexual activity.
  • Depending on the adequacy of the response or side effects, the dose may be increased to 200 mg or decreased to 50 mg a day.
  • Individuals who are taking medications that moderately increase the blood levels of avanafil should not exceed a total dose of 50 mg in 24 hours 

What drugs interact with avanafil?

Is avanafil safe to take if I'm pregnant or breastfeeding?

  • Avanafil is not approved for use in women.
  • Avanafil is not approved for women and has not been evaluated in women who are breastfeeding.

What else should I know about avanafil?

What preparations of avanafil (Stendra) are available?
  • Tablets: 50, 100, and 200 mg.
How should I keep avanafil (Stendra) stored?
  • Avanafil should be stored at room temperature between 20 C and 25 C (68 F and 77 F).


Avanafil is a medication prescribed for the treatment of impotence (erectile dysfunction) in men by helping the persistence of cyclic guanosine monophosphate (cGMP), which leads to more prolonged engorgement of the penis with blood. The most common side effects of avanafil are facial flushing (reddening), headaches, back pain, nasal congestion, dizziness, upper respiratory tract infections, diarrhea, nausea, and flu-like symptoms. Avanafil is not approved for use in women.

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Medically Reviewed on 1/20/2023
Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine


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