Diabetes drugs prescribed to thousands of Britons could double the risk of heart failure, experts have warned.
An analysis of existing studies by UK and US researchers found an increased risk for patients on rosiglitazone (Avandia) and pioglitazone (Actos).
The medicines are approved by the National Institute for Health and Clinical Excellence for use on the NHS to treat Type 2 diabetes.
Researchers estimated that one in every 50 patients taking the drugs over a 26-month period would suffer heart failure and need admission to hospital.
The drugs are not recommended for people suffering from, or at risk of, heart failure. But the new study suggests an increased risk even for those who have never suffered heart failure.
More than 1.9 million people in the UK are Type 2 diabetic and up to 750,000 more are undiagnosed.
Type 2 is linked to lifestyle factors such as obesity, and experts believe up to half of all cases could be prevented through changes to diet and exercise.
The charity Diabetes UK estimates that about 100,000 people in the UK are prescribed Avandia.
Two advisory panels for the US Food and Drug Administration are re-examining both drugs in light of concerns about their risks. The meetings were convened after a study in the New England Journal of Medicine in May linked Avandia to a 43% increased risk of heart attacks.
The research, published in the journal Diabetes Care, was carried out by experts at the University of East Anglia and Wake Forest University in North Carolina in the US.
