Apparently the deficiencies in the backup manufacturing facility for Forest Laboratories' (NYSE:FRX) and Mylan's (NYSE:MYL) Bystolic didn't take that long to fix. A little more than two weeks after the duo received an approvable letter for the product, they reported yesterday that the FDA had signed off on its marketability.

Mylan licensed the U.S. and Canadian rights to the drug from a Johnson & Johnson (NYSE:JNJ) subsidiary in 2001, and then licensed them to Forest last year. Mylan will pick up royalty payments on the sales for acting as the intermediary and has the right to co-market the drug.

Even with 72 million Americans suffering from high blood pressure, it will be an uphill battle for Forest's sales reps. Bystolic will have a lot of competition, with 18 other beta blockers on the market -- talk about drugmakers spinning their wheels.

Bystolic does have a slightly better side effect profile than the other beta blockers, which sometimes cause fatigue and sexual dysfunction, but that might not be enough for it to compete with generic versions of Wyeth's (NYSE:WYE) Inderal and GlaxoSmithKline's (NYSE:GSK) Coreg. With Bystolic being priced at almost eight times the price of generic beta blockers, getting doctors to prescribe it doesn't look like an easy task.

Still, if Forest could eventually reach the level of U.S. sales that AstraZeneca (NYSE:AZN) has managed for Toprol XL -- $883 million in the first nine months of this year -- even in the face of direct generic competition, that would be a substantial addition to Mylan's and Forest's bottom lines. Forest plans to begin marketing the drug next month, so investors should know fairly soon how the drug is competing.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.