The Food and Drug Administration today approved Stendra, a new pill in the same drug class as Viagra, Levitra and Cialis, which reportedly offers men with erectile dysfunction the possibility of achieving an erection in as little as 15 minutes.

Stendra, the brand name for avanafil, will be available in three doses: 50, 100 or 200 milligrams, and should be prescribed at the lowest dose that provides a benefit,  the FDA said. In clinical trials reviewed by the agency, participants reported "statistically significant" improvements in erectile function, vaginal penetration and successful intercourse with all three Stendra doses.

Today's FDA action marks the first drug  approval for Vivus Inc., of Mountain View, Calif., which licensed U.S. marketing rights to avanafil from Mitsubishi Tanabe Pharma Corp. of Japan. Vivus is the biopharmaceutical company behind the diet drug Qnexa, which remains under FDA review.

An estimated 30 million U.S. men have some degree of what used to be called impotence. With the arrival of Viagra, the little blue pill destigmatized the condition and gave it a new name: erectile dysfunction, or ED.

"This approval expands the available treatment options to men experiencing erectile dysfunction, and enables patients, in consultation with their doctor, to choose the most appropriate treatment for their needs," said Dr. Victor Kusiak,  a deputy director within the FDA's Center for Drug Evaluation and Research.

Stendra is the newest of the phosphodiesterase type 5 (PDE5) inhibitors, which include Viagra (sildenafil), Levitra (vardenafil) and Cialis (tadalafil). All boost blood flow to the penis to help men achieve and sustain an erection. However, Stendra tablets, to be taken 30 minutes before sexual activity, go to work in as little as 15 minutes, according to clinical trial results submitted to the FDA.

"Quick onset of action is important to men," Dr. Ira Sharlip, a urology professor at UC San Francisco, and former president of the International Society for Sexual Medicine, told ABCNews.com.

In an interview Thursday, on the eve of the FDA decision, Sharlip said Stendra likely would appeal more to ED sufferers "whose opportunities for sexual activity are more casual," than to those who have sex on a more predictable basis.

Clinical trial results with more than 1,200 men indicated that Stendra also clears the body more quickly than the other ED drugs in the same class, according to data submitted to the FDA.

In a Phase II study, Stendra worked as well as Viagra while producing less low blood pressure in cardiac patients who take nitroglycerin. In the two Phase III trials that compared Stendra with a placebo, there were no reports of blue vision or prolonged, painful erections (priapism), which are infrequent side effects associated with Viagra. In rare cases, men taking any of the PDE5 drugs have reported sudden decreases in hearing or loss of hearing.

Any patient who experiences sudden loss of hearing or vision while taking any of the PDE5 drugs should call a doctor right away, the FDA said.

Sharlip said he didn't believe that those rare side effects matter much to most patients. "Despite what the FDA says, I have never seen priapism from any PDE5 inhibitor drug. Priapism is just not a clinical problem. Blue vision with Viagra is uncommon and at worst annoying. Most men who get the blue vision with Viagra don't care about it," he said.

The most common side effects of Stendra were headache, flushing, stuffy nose, mild cold symptoms and back pain.

The drug already has been approved for use in South Korea under the brand name Zepeed.

The most recent FDA approval of an ED drug came in 2010 for Staxyn, a version of vardenafil that dissolves under the tongue, rather than being swallowed.