HEALTH: Statin potency tracks muscle problems, study finds


Those taking stronger  statins  to lower their cholesterol  experience  muscle side effects more frequently than those who take weaker ones, according to a UC San Diego-led study published  Wednesday in PLoS One .

The study looked at several different muscle problems, including rhabdomyolysis , which can cause kidney damage. It also included less severe side effects, such as muscle pain. It emphasized the importance of following up on the effects of drugs long after they reach the market, not just in clinical trials.

Crestor, the most potent statin, topped the list with the most frequent muscle problems, the study found. It's known generically as  rosuvastatin . In order of rate of muscle side effects, Crestor was followed by  atorvastatin , sold as Lipitor and recently approved for sale as a generic;  simvastatin , sold generically and under the brand name Zocor;  pravastatin , sold generically and as Pravachol; and  lovastatin , sold as Mevacor.

The findings are of concern to tens of millions. Cardiovascular disease is the top killer in the United States, and indeed the Western world. Unsurprisingly, cholesterol-lowering statins are among the most-prescribed medications. And there's a lively medical debate about the usefulness of statins, and who will benefit from them.

Study investigator  Beatrice A. Golomb  of UCSD reported earlier this year that those taking statins are more fatigued than a control group. On the other hand, those who take statins after having had heart attacks have been found to have a lower incidence of additional "cardiovascular events."

"Incorporating all muscle categories, rates for atorvastatin, simvastatin, pravastatin, and lovastatin were, respectively, 55 percent, 26 percent, 17 percent, and 7.5 percent as high, as rosuvastatin, approximately tracking per milligram potency," the study stated.

Since statin potency correlates with muscle problems, strength appears to be a "dominant factor" in how likely these problems are to occur, Golomb said in a UCSD  press release . She directs the  Statin Adverse Effects Study  at UC San Diego.

Other study authors were Keith B. Hoffman, Christina Kraus and Mo Dimbil of  Adverse Events Inc. , a Healdsburg-based company that provides the public  information on drug side effects .

The reseachers looked through FDA records of millions of statin prescriptions from July 1, 2005, to March 31, 2011.

During that period, simvastatin was precribed 122.4 million times. For the others, the numbers are: Atorvastatin 105.3 million; rosuvastatin 35.5 million; lovastatin 26.3 million; pravastatin 27.8 million; and fluvastatin 3.3 million.

The outlier

Fluvastatin appears to be an exception, the study said. The least potent statin, fluvastatin was associated with a risk of muscle problems 74 percent as high as Crestor.

"Relative risk rates for rosuvastatin were consistently higher than other statins," the study stated. "Atorvastatin and simvastatin showed intermediate risks, while pravastatin and lovastatin appeared to have the lowest risk rates. Relative risk of muscle-related AEs, therefore, approximately tracked with per milligram LDL-lowering potency, with fluvastatin an apparent exception."

Fluvastatin's status as an exception was also found in research published in 2010, the study said. 

"We think a likely reason is that fluvastatin, which is far less frequently prescribed than other statins, may be primarily reserved by physicians for patients who have failed to tolerate other statins," the study said.


