Crestor, the most powerful of the cholesterol-lowering statin drugs, has higher rates of serious adverse effects including, rhabdomyolysis (severe muscle deterioration) and kidney failure, than rival drugs, according to a study published Tuesday in the online journal of Circulation: Journal of the American Heart Association.

The study is the latest unfavorable report for Crestor, which has been amid controversy since launched by AstraZeneca in 2003. In March, the Food and Drug Administration said Asian American patients taking Crestor may be at greater risk of muscle injury because of Crestor than the general public. The announcement came after AstraZeneca revised the package insert for Crestor, advising doctors to consider using lower starting doses of the drug in some individuals as a means of reducing risk of rhabdomyolysis. In March 2004, Public Citizen, a consumer advocacy group, called on the FDA to withdraw Crestor from the market, citing cases of patients with life-threatening side effects.

In the study, researchers analyzed post-marketing data from the U.S. Food and Drug Administration (FDA) on statins. They measured the data by recording rates of adverse event reports (AERS) per million prescriptions. Data from the first year of Crestor�s marketing were compared with concurrent data from Lipitor, Zorcor and Pravachol.

Researchers found Crestor was more likely to be associated with muscle damage (myopathy) compared to Lipitor, Zorcor and Pravachol. They also said the occurrence of rhabdomyolysis and kidney toxicity relatively early after initiation of therapy (within 12 weeks on average), suggests that vigilant surveillance for adverse effects during initiation of therapy may help lighten the risk of toxicity when Crestor is used.

Crestor is the strongest statin available because it has the greatest effect per milligram on �bad� cholesterol. Worldwide sales of Crestor were $908 million in 2004.

In a statement, AstraZeneca said: “Conclusions published in Circulation today regarding Crestor are misleading, and unfortunately create unnecessary alarm for patients who need this medication to lower their cholesterol.”

The American Heart Association said patients who are currently taking Crestor or any other statin should continue to take their medication as prescribed and consult with their physician if they have any question about dosage or risk of side effects. According to the AHA, the only time patients should stop taking their statins is if they experience muscle pain or dark urine, and they should notify their physician immediately.

(via American Heart Association)