FDA Limits High-Dose Zocor Over Muscle Damage

More than a year after issuing a warning that the highest dose of the Zocor cholesterol pill could cause serious muscle damage (see here), the FDA is now saying the 80 mg dose should be avoided, except by patients who have taken this dose for 12 months or more and not experienced any muscle problems. The latest warning also applies to the highest dose of another Merck pill - Vytorin, a combe med that includes Zocor - as well as Simcor, which is sold by Abbott Laboratories.

The move was made after the agency reviewed a seven-year study conducted by Merck and other clinical trial data, as well as adverse event reports, all of which showed the highest dose had an increased risk of myopathy, or serious muscle damage. The risk was highest during the first year of treatment with the 80 mg dose and often occurred while interacting with other meds, although a genetic predisposition was also cited (here is the FDA statement).

Other regulators also issued warnings about the high dose, such as the UK’s Medicines and Healthcare products Regulatory Agency (look here). Overall, though, Zocor has remained popular - the pill was prescribed 94 million times in 2010, twice the number of prescriptions in 2007, according to Forbes, which cited IMS Health research data. However, Merck says only 12 percent of patients were taking the 80 mg dose (read the statement).

The most serious form of myopathy, by the way, is rhabdomyolysis, which can lead to severe kidney damage, kidney failure, and sometimes death. A decade ago, in fact, Bayer withdrew its Baycol cholesterol pill due to this side effect. The development prompted scrutinty of all statins. Three years later, as Forbes noted, Cleveland Clinic cardiologist Steve Nissen wrote an editorial in the Journal of the American Medical Association that the 80 mg dose of Zocor “was associated with an unusually high rate of myopathy” (read here). His warning proved prescient.

Of course, the FDA is perennially stretched thin and safety reviews require a great deal of certainty and care. But the agency had been looking at the Merck study, which was called SEARCH, for the past two years. So what do you think?