Doctors firmly believe cholesterol-lowering statin drugs are a good thing. But too much of a 'good thing' can harm you - and even kill you, say scientists who have discovered the safest level for statins.
Statins can cause muscle pain and weakness, and this can even lead to a complete breakdown of muscle tissue. In rare cases, they cause renal failure and death.
These reactions depend on the concentration of statins you have in your blood - and deaths have been recorded among patients who have been taking the minimum daily dose of 20 mg. Overall, statins cause myopathy, or muscle weakness, in one out of every 10,000 patients, which, according to researchers at Oxford University, is an 'acceptable' level.
However, as 8 million Americans take a statin drug every day, this suggests that at least 800 people develop myopathy after taking the drug every year. In fact, the figure is far higher because these statistics are based on the standard 20 mg dose. Many patients are taking either the 80 mg dose or are taking a statin in association with other drugs, which can also have a 'magnifying' effect.
When the Oxford researchers tested the 80 mg dose on 6,031 patients, 98 of them - or 1.6 per cent - went on to develop myopathy. Extrapolated across the whole statin market, this suggests that up to 128,000 patients in the USA alone could develop myopathy as a result of taking a statin.
So, say the researchers, the only 'safe' dose is the smallest, and patients shouldn't be given more than 20 mg a day.
(Source: New England Journal of Medicine, 2008; 359: 789-99).