Counterfeit Drugs
Drugmakers are hoping that their newer drugs could help offset the revenue lost from former top-sellers. Reuters

Stendra, the first new drug to enter the erectile dysfunction market in nearly a decade, hopes to become the new, faster-acting Viagra alternative after receiving approval from the Food and Drug Administration.

The drug's creator Vivus Inc. claims the pill could actually work faster than its rivals, Pfizer's Viagra and Eli Lilly's Cialis and Levitra, especially if the patient gives it a head start by setting the mood ahead of time.

If things are heated up, theoretically you can get improved function earlier, within 15 minutes, with this drug, Dr. Irwin Goldstein, director of sexual medicine at Alvarado Hospital in San Diego, and co-author of a recent study about Stendra in the Journal of Sexual Medicine, told CNN. You can argue this is the first potential on-demand drug.

Stendra's fast-acting nature, which has yet to be proven within larger populations, means men could spend less time preparing. It has a rife market, with 30 million U.S. men suffering from erectile dysfunction, according to the FDA.

Stendra has many of the usual side effects expected from ED drugs, including headaches, flushing, back pain and a stuffy nose. The FDA suggested patients be mindful of less-common but more dangerous occurrences of blurry or complete loss of vision, a sudden drop in blood pressure or loss of hearing. The FDA's approval was based on clinical trials with 1,267 patients for 12 weeks.

Goldstein said the drug would not replace Viagra for many men, as each drug has its own level of effectiveness for patients.

There is no drug that is the best, said Dr. Laurence Levine, a professor in the department of Urology at Rush University Medical Center in Chicago, who was not a part of the Stendra study. Each patient's own chemistry may make one drug better than another. There are certain advantages and disadvantages to all of these drugs.