After gaining Food and Drug Administration approval nearly a year ago, patients can finally walk into a pharmacy and get their prescription for VIVUS' (NASDAQ:VVUS) weight loss drug Qsymia.

The drug has been on the market in the interim, but it was only available through mail-order pharmacies. The FDA required the extra regulation because Qsymia can cause birth defects if pregnant women take the drug.

Earlier this year, the FDA lightened up the requirements, allowing the company to certify retail pharmacies to hand out the medication. The first batch is done; on Monday, VIVUS said Qsymia is now available in approximately 8,000 Walgreens, Costco, and Duane Reade retail pharmacies nationwide. VIVUS plans to certify more pharmacies in the coming weeks and months.

Having retail pharmacies in the mix should help with sales. Doctors will have fewer steps to prescribe the drug, and patients that typically go to retail pharmacies for their medication can follow their usual routine, albeit not necessarily at the pharmacy they typically frequent.

The change couldn't come soon enough. Sales of Qsymia in the first quarter were just $4.1 million. The company spent ten times that trying to convince doctors to prescribe it and on other administrative expenses. And VIVUS now has competition from Arena Pharmaceuticals (NASDAQ:ARNA) and Eisai's Belviq, which hit pharmacies last month.

While the move to retail pharmacies was a necessary step toward increasing sales, it won't be sufficient. For VIVUS, Arena, and Eisai to get sales to blockbuster status, the companies have to change doctors' treatment regimen for obesity, which has generally shunned drugs for diet and exercise.

The risk-benefit for diet and exercise -- assuming that patients stick with it -- far exceeds the risk-benefit for drugs. After Wyeth's Fen-Phen and Abbott Labs' Meridia were pulled from the market, doctors are also concerned with risks that might not be uncovered until a large number of patients have taken the drugs. If it's approved, Orexigen (NASDAQ: OREX) obesity drug Contrave will have the advantage here since the company is running a large trial to exclude the possibility that Contrave increases cardiovascular-related side effects.

The companies also have to convince payers -- health insurers and the government -- to pay for the drugs, which have typically been considered lifestyle drugs. VIVUS has said that it's shooting for 50% of lives covered by insurance to have coverage for Qsymia by the end of the year. Even then, the copay is likely to be high enough that some patients will be unwilling to shell out for the drug even if it is more convenient to get their prescriptions.

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