New generics quickly grab 80% of sales volume

U.S. drug spending didn't just hit a growth slump last year. In another worrisome development for drugmakers, generics took every slot on the list of the 10 most-prescribed drugs compiled by IMS Healthcare Informatics; only three branded drugs made the entire ranking of 25, the Wall Street Journal Health Blog reports.

What's more, all three of those drugs--Pfizer's cholesterol med Lipitor; the Sanofi-Aventis/Bristol-Myers Squibb blood thinner Plavix; and Merck's allergy/asthma remedy Singulair--are set to lose patent protection by next year. So we may soon find that all of the 25 most popular prescription drugs are generics.

The drug that generated the most prescriptions was the painkiller combo drug hydrocodone/acetaminophen, otherwise known in branded form as Vicodin. Pharmacists handed out more than 131 million prescriptions for that drug in 2010. As the Health Blog notes, that's a whopping 37 million more than the second-place drug simvastatin, the knockoff version of Merck's cholesterol drug Zocor.

Meanwhile, the IMS report illuminated another scary piece of news--for branded drugmakers at least--generics capture the market for a particular drug much more quickly than they did in the past. Within six months of a patent loss last year, generics had taken more than 80 percent of sales volume from the branded version. Just four years ago, generics were only able to grab 55 percent of the market within six months.

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