Doctors may be underestimating the risks of paracetamol, the world’s most popular painkiller.

Researchers found chronic users of the drug – people who typically take large, daily doses over several years – may increase their risk of death, or kidney, intestinal and heart problems.

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Scientists from the Leeds Institute of Rheumatic and Musculoskeletal Medicine analysed eight studies on people who had paracetamol prescribed by a doctor, as opposed to over-the-counter purchases.

Two of the eight studies had found an increased risk of mortality, up to 63 per cent, among long-term paracetamol users, compared to those who had not been prescribed the drug during the study period.

Four found a heightened risk, ranging from 19 to 68 per cent, of cardiovascular problems. The risk of gastro-intestinal bleeding and other intestinal side-effects was up to 49 per cent as high.

Three studies found an adverse effect on kidneys.

In all cases, the risk was dose-dependent – in other words, the higher the dose, the greater the risk, said the analysis published in the British journal Annals of the Rheumatic Diseases.

Even though the risk in absolute terms was small, doctors should think carefully when prescribing the drug, it warned.

But other experts cautioned against over-reaction.

They pointed out the analysis was unable to tell whether early death and health problems were caused by an underlying illness rather than from the paracetamol.

Nor did it take into account over-the-counter purchases of the drug, a picture that could be far more complex.