Yet another problem for Merck. The agency says there's a potential for increased risk of muscle injury from the 80 mg dose of Zocor, or simvastatin, as the generic is known. In issuing its warning, the FDA notes muscle injury, or myopathy, is a known side effect with all statins, but this new concern highlights "the greater risk of developing muscle injury, including rhabdomyolysis" while on the highest dose.Rhabdomyolysis is the most serious form of myopathy and can lead to severe kidney damage, kidney failure, and sometimes death. The agency review ( see here) was based on info from clinical trials, observational studies, adverse event reports, and prescription use data. The FDA is also reviewing the SEARCH (Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine) trial, which evaluated major cardiovascular events, such as heart attack, revascularization and cardiovascular death, in patients taking 80 mg compared to 20 mg of simvastatin. This included data on muscle injury in patients taking simvastatin.
Although the problem is confined to the highest dose and Zocor is already sold as a generic, this can become an issue for Merck, given that Vytorin contains two drugs, Zetia and Zocor. Last year, Vytorin sales reached $2.1 billion.