Zocor, or simvastatin, has been one of the most widely used cholesterol-lowering agents in the world for the past 20 years - and only now doctors have discovered its dangers and its ineffectiveness.
Heart specialists are looking for better alternatives after discovering high-dose simvastatin can cause muscle weakness, or myopathy. Last year the Food and Drug Administration (FDA), America's drug regulator, warned that simvastatin could lead to fatal kidney failure, especially if it is used with another drug, amiodarone.
Worst of all, doctors aren't sure that simvastatin is effective.
Despite these concerns, simvastatin has become one of the world's most successful drugs, with annual sales reaching $4.3 billion in 2005. It is also available as an over-the-counter remedy in the UK.
(Source: Journal of the American Medical Association, 2009; 301: 261-2).