Millions of people prescribed cholesterol-reducing statins should continue to take them because the benefits outweigh the risks, Britain's medicines regulator said on Friday. The Medicines and Healthcare products Regulatory Agency (MHRA) issued a safety update following a row over the frequency of side effects from the drugs. It said evidence from large clinical trials showed statins could save lives by reducing the risk of heart attacks, strokes and the need for heart surgery.

Its advice to health professionals said at least 450 deaths from heart attacks, stroke or vascular failure would be prevented for every 10,000 patients treated, if patients with a 20% risk or more of suffering such a cardiovascular event over a 10-year period took statins for at least five years.

The update came after the British Medical Journal(BMJ) commissioned an independent panel to report on how claims that 18-20% of people on statins suffered adverse events were published in the journal last year .

The verdict is expected by the end of July. The authors of two articles using the figure, John Abramson, from Harvard medical school, and Aseem Malhotra, a UK cardiologist, have withdrawn statements on the frequency of side effects following a charge from Prof Sir Rory Collins of Oxford University that the information was inaccurate and could endanger lives.

Collins, a leading advocate of statins, has argued that both articles should be withdrawn completely, saying they had caused uncertainty in patients. He suggested they could lead to far more harm than the scare over the MMR vaccine caused by the now discredited Andrew Wakefield.

Statins are currently being taken in Britain by about 7 million people who have at least a 20% risk of a heart attack or stroke in the next 10 years. The National Institute for Health and Care Excellence (Nice) recommended in February that statins should be given to people at only 10% risk – a move that could dramatically increase the number of people taking them.

The five types of statin prescribed in Britain are taken once a day, often last thing at night, and most patients will take them for the rest of their lives. They can interact with other medicines.

The MHRA's new overview of evidence recognises statins, "like all medicines", can cause side effects in some people – mostly mild and most frequently muscle-related – but says most people should continue to take the drugs.

It reminds prescribers to advise patients to seek prompt medical attention if they experience muscle problems while on the drugs. For some patients stopping statin treatment may be appropriate. If statin treatment must be continued despite the muscle problems, prescribers should consider using a lower statin dose or switching to a different statin, the advice says.

"The benefits of using any statin in its licensed indication outweigh the risks in most patients", it says. But the "potential benefits and harms" must be considered in each case.

June Raine, MHRA's director of vigilance and risk management of medicines, said: "The MHRA continually reviews the information on the safety of statins. We will update the prescribing advice for statins in light of any substantial new evidence of safety concerns. If patients have any concerns about their medicines then they should speak to their doctor.

"If you think you have suffered a side-effect to any medicine, please tell us about it through our Yellow Card scheme at www.yellowcard.mhra.gov.uk."