Vivus, the manufacturer of a new erectile dysfunction drug  Stendra (Avanafil), says the pill can work in as little as 15 minutes.  If this is the case then Stendra (Avanafil) will be the first “on-demand drug” sex and erectile dysfunction.

Erectile dysfunction, or the inability to keep an erection, affects more than 30 million men in the U.S., and sales of treatment drugs exceeded $5 billion last year.

Viagra is estimated to achieve $2 billion in sales next year, but the newly FDA-approved Stendra (Avanafil) may be a serious competitor, likely to cut into future profits.

What is Stendra (Avanafil) exactly?

The FDA-backed medication, known chemically as avanafil, is in the same class as drugs as Viagra, Cialis, and Levitra. All of them work to increase blood flow to the penis but what separates Vivus Stendra (Avanafil) from its competitors is its ability to work 30 to 60 minutes faster than other pills.

While Stendra (Avanafil) is supposed to be taken 30 minutes before sexual activity, studies have shown that the drug can work in as little as 15 minutes.

Dr. Irwin Goldstein, co-author of a recent study looking at Stendra's (Avanafil) effectiveness says "You can argue this is the first potential on-demand drug [for sex]”.

Who makes it?

Stendra (Avanafil) is made by Vivus, Inc., based in Mountain View, California. The company is also responsible for the anti-obesity pill Qnexa, which is pending FDA approval.

Does Stendra (Avanafil) have side effects?

Common side effects include headaches, redness of the face, nasal congestion, and back pain.

Like Viagra and other PDE5 inhibitors Stendra (Avanafil) can cause "colour-vision changes," and a few people have reported sudden loss of vision in one or both eyes, as well as loss of hearing.

Stendra (Avanafil) shouldn't be taken by men who take nitrates for chest pain because the combination of the two drugs can cause an unsafe drop in blood pressure.

Should Viagra's makers be worried?

Stendra (Avanafil) is projected to generate around $68 million in sales next year, so while it is expected to sell well, this is a paltry amount when compared with Viagra's estimated $2 billion. As such, it is unlikely to be a Viagra killer.

There are actually larger concerns on the horizon for both companies: Patents for Cialis and Levitra will expire in 2016 and 2018, respectively, meaning "generic competition" is on the horizon. And non-branded Viagra is expected to hit pharmacies as soon as 2019.

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