DALLAS – Contrary to government claims, side effects happen more often with Crestor (search), a cholesterol-lowering drug that consumer advocates tried to get off the market earlier this year, a new analysis shows.
The review of leading cholesterol drugs taken by millions of Americans showed that most are very safe and that the risk of serious problems, even with Crestor, are very low. But the latest research seemed to challenge a Food and Drug Administration (search) decision not to pull the drug off the market.
In March, the FDA had contended Crestor's risks were no greater than its competitors, and it rejected consumer efforts to remove the drug, made by AstraZeneca PLC (search), from store shelves. Instead, the FDA ordered a warning on the label, saying Crestor could cause serious muscle problems and kidney damage, especially among Asians.
The new study, based on side effects reported to the FDA, said that kidney problems and severe muscle weakness were two to eight times more frequent among Crestor users than those taking other statins.
"This will be further reason to take the drug off the market," said Dr. Sidney Wolfe of the consumer group Public Citizen. He said his group would try again to get the drug off the market.
FDA spokeswoman Laura Alvey said that the new analysis yielded no new information. "We haven't found any convincing evidence that Crestor poses any more of a risk than the other statins," she said.
The drug's maker, AstraZeneca, said the higher reports of side effects may have been the result of heightened awareness of the problems with another cholesterol drug, Baycol, which was pulled from the market in 2001. Crestor went on the market two years later.
"We strongly disagree with the conclusions of this study," the company said in a statement.
Shares of AstraZeneca fell 36 cents, or 0.8 percent, to $42.41 in after-hours trading Monday after the study was released.
An estimated 20 million Americans are believed to be taking drugs called statins, which researchers say are still the best drugs for lowering high cholesterol and reducing the risk of heart disease and stroke.
Many of the drugs cause muscle problems among some people, but experts advise patients to talk to their doctors about lowering their dosage, which can solve the problem. Doctors said patients should not stop taking statins but should discuss any problems with their doctors.
In a teleconference, doctors reiterated that the drugs are safe overall.
"Statins in general are very safe drugs and they can be life-saving to high-risk patients," said Dr. Scott Grundy, of the University of Texas Southwestern Medical Center in Dallas.
For the new study, funded by the American Heart Association and published online Monday by the association's journal Circulation, researchers analyzed reports of side effects sent to the FDA for Crestor and compared them to the rates during the same time period for three other statins: Lipitor, Zocor and Pravachol.
"What we've shown is that amongst this family of drugs, Crestor has a poorer safety profile, but that the overall rate of adverse effects is still quite low," said study leader Dr. Richard Karas, director of the preventive cardiology at Tufts-New England Medical Center in Boston.
Karas, who has received research grants and speaker fees from several drug companies — including the maker of Crestor — said that generally, the people who should consider taking Crestor are those who are unable to lower their cholesterol enough with other drugs or those who may be allergic to other drugs.
The year after Crestor came on the market in October 2003, more than 5 million prescriptions were filled for the drug.
The researchers also compared the rate of adverse event reports during the first year of marketing for the current statins and the earlier withdrawn drug, Baycol.
Complications were more common with Crestor than the other three statins available, but less than half the rate of those reported during the first year of Baycol's use. But even for Crestor, the absolute risk of a serious problem was very low — 1 in 35,862.
When side effects did occur, it tended to be within the first three months' of use. Only a few deaths occurred among the millions of users, and death rates were lower among those taking Crestor or Zocor. Karas said that scientists don't know whether the deaths were caused by the statins.
An expert and the study's authors agree that there were limitations to the study, including the possible underreporting of side effects. Also the removal of Baycol from the market likely heightened public awareness of drug safety concerns.
Dr. Benjamin Ansell, co-director of the cholesterol treatment program at UCLA medical center in Los Angeles, suggested there is also a tendency to overreport side effects, especially when a drug, like Crestor, has gotten a lot of media attention.
"I would say the study has to be interpreted with skepticism and recognizing its imitations," Ansell said.
Also, he said, those who were put on Crestor when it came out were likely those who had had problems with other statins.
"The people who are 'problem patients' ... are more likely to get Crestor," he said.
The bottom line, he said, is that the statins have an excellent safety record.