DOCTORS who blindly prescribe recommended drugs for common conditions such as type 2 diabetes and heart failure often leave patients at risk of serious complications caused by taking different medications at the same time.

Researchers at Dundee University examined 12 conditions and looked at the National Institute of Health and Care Excellence guidelines for potential clashes between different drugs.

They found that there were 133 potentially serious interactions between medications for drugs recommended for type 2 diabetes. They discovered a further 111 for heart failure and 89 for depression.

Professor Bruce Guthrie, of Dundee University, said the findings showed that clinical guidelines needed to take greater account of patients suffering from more than one condition.

He said: "Despite widespread multimorbidity, where patients have more than one condition, the clinical guidelines are largely written as though patients have a single condition and the cumulative impact of treatment recommendations from multiple guidelines is not really considered.

"Clinical guidelines of course are not intended to be completely comprehensive guides to practice, in that clinicians are expected to use their judgement in deciding which treatments are appropriate in individual patients.

"However, it is potentially dangerous to have guidelines that do not take account of the effect of combinations of recommended treatments."

The study, published in the British Medical Journal, was carried out by Dundee University along with researchers from Aberdeen, Glasgow and Manchester universities.

The researchers said that potentially serious clashes between drugs prescribed for different conditions were "common".

Mr Guthrie said: "We recommend that during the development of clinical guidelines the process should consider how to identify and more explicitly highlight the potential for interactions between recommended drugs and other conditions and other drugs that patients with the guideline condition are likely to have.

"The number of potentially serious combinations of drugs and diseases requires a better approach to multimorbidity to allow clinicians and patients to make informed decisions about drug treatments."