When the FDA announced that the popular cholesterol drug simvastatin, brand name Zocor, would need a new label warning, it simply reinforced something that many doctors already knew: The highest “recommended” dose of 80 milligrams a day is so dangerous that it probably shouldn’t be recommended at all.
Like other statin drugs, Zocor (generic name simvastatin), can cause muscle weakness and pain, which is annoying but not especially dangerous. But high doses of any statin can be toxic to muscles. In extreme cases, the muscles break down and release dangerous proteins that can damage the kidneys. This complication, known as rhabdomyolysis, can be fatal.
It’s not exactly news that Zocor, an older statin that was first approved by the FDA in 1991, seems to be riskier than other statins, especially at the high-end dose of 80 milligrams a day. The FDA itself warned about this danger in a “safety announcement” last year. At the time, the agency noted a study showing that about 1% patients taking 80 milligrams a day suffered from muscle damage. The same study included more than 6,000 patients taking 20 milligrams of Zocor a day; only one of them developed the muscle problem.
The FDA now says that doctors should no longer prescribe 80 milligrams of Zocor unless a patient has already been taking the dose for a year without any apparent trouble. But not everyone agrees that the warning goes far enough.
“We believe that the 80-milligram dose should be taken off the market completely,” says Dr. Michael Carome, deputy director of the Health Research Group for Public Citizen, a consumer protection group. Carome notes that high doses don’t seem to be much more effective than lower doses. “But the more you take, the greater the risk,” he says.
Since their discovery in the 1980s, statins have had kind of an on-again, off-again reputation as miracle drugs. They can definitely reduce the risk of a heart attack, especially for people who already have heart disease. If you’ve already had a heart attack, they can cut your risk of another attack by about one third.
But heart disease is complicated, and no single drug can protect a person. A recent two-year study found that treating heart attack patients early and aggressively with statins reduced the risk of further heart trouble, but nearly 15% of patients still suffered another heart attack, had to be readmitted to the hospital, or died before the study was over.
The FDA could have possibly moved faster to sound the warning on simvastatin, says James Backes, an associate professor of pharmacy practice at the University of Kansas. But at least the message is out now. “There are safer and more effective statins out there,” he says. “You have to be careful with these drugs.”