According to a new study, the potency of statins is the reason behind muscle pain in people who use the drug.

Statins are known to help against heart disease and stroke by lowering the levels of low-density lipoproteins (LDL), or bad cholesterol, in the body. In the U.S., approximately 30 million people use statins and the drugs have brought in over $19 billion in domestic sales. Statin use has been known to result in muscle-related problems in 10 to 15 percent of all users. The present study found that the strength of the drug can result in muscle pain and weakness.

"These findings underscore that stronger statins bear higher risk - and should be used with greater caution and circumspection," said Beatrice Golomb, MD, professor at University of California, San Diego.

For the study, researchers analyzed medical records of more than 147,000 reports in the Food and Drug Administration's Adverse Event Reporting System (AERS) gathered between March 2005 and July 2011.

The study found that rosuvastatin, the most potent statin, had the highest number of muscle related reports followed by atorvastatin, simvastatin, pravastatin and lovastatin.

"These rankings closely match the individual potencies of each statin. Thus, the strength of the statin drug appears to be a dominant factor in determining how likely muscle problems are to occur," said Golomb.

"Only a fraction of adverse effects are reported to the FDA, and a range of factors can influence reporting rates and accuracy of this information. However, findings from this study align with - and extend- other forms of evidence," Golomb said.

Recently, the FDA had added warnings about risk of higher blood sugar levels and memory loss due to statin use.

Researchers suggest that people who have stopped statin use due to muscle-related problems can probably re-start the medication with a lower dose.

"Our findings suggest that individual statin potency is a critical determinant of how likely a statin is to cause problems. This information should help guide prescribing decisions for statins by offering more information on the risk-benefit profile of the class. It should also be important for guiding decisions about statin selection and use after a patient has experienced a muscle-related adverse event," Golomb concluded.

The study is published in the journal PLoS ONE.