More than three million extra people at risk of heart attacks or strokes will be able to take statins from today, following the publication of new guidance to GPs.

The National Institute for Clinical Excellence (Nice), which recommends drugs for the health service, has widened its criteria for patients eligible to be given the cholesterol-lowering treatment.

Before today, only those who had a 30% risk of coronary heart disease in the next 10 years were eligible for the drug, though those who had had a heart attack or stroke were given it in practice. Under the new rules, the risk has been reduced to 20% and applies to all those at risk of cardiovascular disease (CVD), which can lead to heart attack, angina and stroke.

The new guidance means the number on statins could rise to one in 10 of the adult population. A total of 1.8 million receive the drug currently. The Department of Health estimates the treatment saved 9,000 lives in 2004, meaning more than 20,000 lives a year could now be saved.

The drugs are prescribed to reduce cholesterol, the fat-like substance that can build in arteries, and are sometimes given after a heart attack or stroke to cut the risk of a recurrence.

Nice has estimated that the revised guidance could cost between £55m and £82m a year. But it stressed that savings gained through prevention could mean the extra cost was £17m. This assumes GPs prescribe the cheapest statins - costing £30 a year - rather than the most expensive, costing £360.

Publishing the guidance, Professor David Barnett said its potential impact was "one of the most significant" to come out of Nice in six years. But he stressed: "The guidance also makes the important point that other strategies for managing CVD risk over and above the use of statins - such as stopping smoking and other lifestyle measures - should also be considered when initiating statin therapy."