Millions more Britons could benefit from statins after a landmark review found they do not cause most of the side-effects previously feared.

University of Oxford researchers warn ‘ongoing confusion and concern’ about the drugs has left many missing out on a treatment that is known to prevent heart attacks and strokes.

They are now calling for the information leaflets in statin boxes to be urgently rewritten to avoid the list of unfounded potential side-effects putting people off.

It comes after the experts examined data on 123,940 people from 19 previous trials and concluded the risk of side-effects is ‘greatly outweighed by the benefits’.

Each trial compared the effects of statins to a placebo, or dummy drug, and followed participants for an average of 4.5 years after starting treatment.

Analysis, published in The Lancet medical journal, revealed there is no significant excess risk for almost all of the conditions listed in the package leaflets as potential side-effects.

This includes no increased risk of memory loss, depression, sleep problems, erectile dysfunction, weight gain, nausea, fatigue or headache.

Associate Professor Christina Reith, the lead author of the study, said: ‘What we were able to show reliably was that statins did not make these commonly experienced events occur more often.

‘So for example, the percentage of people suffering memory loss per year was similar to those taking statin therapy as those not.

‘Equally, the percentage of people suffering sleep problems per year was similar to those taking statin therapy as for those not.

‘This means that we now have really good evidence that although these things may well happen to people while they take statins, that statins are not the cause of these problems.’

She added: ‘Our study provides reassurance that, for most people, the risk of side-effects is greatly outweighed by the benefits of statins.

‘What we hope to see happen is that statin drug labels are revised alongside related information to enable doctors and patients to make better informed decisions going forward.’

Statins are among the most widely prescribed medicines in the UK, with around seven to eight million people currently taking them to reduce ‘bad’ cholesterol.

But the British Heart Foundation, which part-funded the review, says another seven to eight million people should take the ‘extraordinary’ drugs to reach ‘optimal treatment levels’.

Previous work has identified a 1 per cent increase in muscle symptoms among people taking statins, usually in the first year of treatment.

And statins can lead to a small increase in blood sugar levels, meaning that some people at high risk of diabetes may develop the condition sooner.

On top of these known side-effects, researchers found that only four of 66 ‘undesirable outcomes’ previously linked to statins were actually associated with the drug.

This included a small increased risk of around 0.1 per cent of abnormal liver blood tests.

But there was no increased risk of serious liver disease, they said.

They also found an increased risk in swollen legs, ankles and feet, also known as oedema, and changes to urine.

Professor Sir Rory Collins, the senior author of the paper, added: ‘Now that we know that statins do not cause the majority of side-effects listed in package leaflets, statin information requires rapid revision to help patients and doctors make better-informed health decisions.’

Professor Bryan Williams, chief scientific and medical officer at the British Heart Foundation, said: ‘Statins are life-saving drugs, which have been proven to protect against heart attacks and strokes.

‘This evidence is a much-needed counter to the misinformation around statins and should help prevent unnecessary deaths from cardiovascular disease.’

Professor Victoria Tzortziou Brown, chair of the Royal College of GPs, said: ‘Those considering taking statins should be reassured by this comprehensive study which shows that while statins, like any medication, have potential side-effects, the risk for most people is low.’