VIVUS (Nasdaq: VVUS) doesn't mess around when it comes to trying to get FDA clearance for drugs that aren't exactly medically necessary.

The company developed an erectile dysfunction drug called Muse, but it never sold very well given that it requires a transurethral injection.

Of course, VIVUS is most famous for its obesity drug, Qnexa. The drug produces substantial weight loss, but side effects resulted in a rejection by the FDA. Competing against diet and exercise means the drug has to be safer than drugs for other indications. The next decision for Qnexa was recently pushed back to July, but looks like it has a higher likelihood of success after the company stratified the side effect risk.

The delay leaves avanafil, VIVIUS' erectile dysfunction drug that uses the more conventional oral method of delivery, as the next opportunity to get a drug on the market. The FDA is set to make a decision by Sunday.

Like obesity drugs, erectile dysfunction drugs have to have a fairly clean bill of health, as not correcting the problem doesn't drastically affect the patient's health. Fortunately avanafil looks fairly safe and it's in the same class of drugs -- PDE5 inhibitors -- as Pfizer's (NYSE: PFE) Viagra, Eli Lilly's (NYSE: LLY) Cialis, and Levitra, sold by Bayer GlaxoSmithKline (NYSE: GSK) and Merck (NYSE: MRK). The precedence with approval of other drugs in the class plus all the real-world experience of patients taking the drugs should help VIVUS get through the FDA gauntlet.

On the efficacy side, avanafil seems to work well and has an advantage over the other erectile dysfunction drugs because it has a quicker onset. The increased speed won't be necessary to get past the FDA, but it should help in attracting patients.

Given the expected approval and the crowded market avanafil is entering, I don't think an FDA approval will do much to excite the shares. Most of VIVUS' value is still tied up in Qnexa.

That's my take -- let us know what you think by taking the poll below.

Fool contributor Brian Orelli holds no position in any company mentioned. Click here to see his holdings and a short bio. Motley Fool newsletter services have recommended buying shares of GlaxoSmithKline and Pfizer. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.