A Canadian study has confirmed the results of previous trials that indicated that sulphonylureas put patients at increased risk of serious cardiovascular events.
The researchers looked at data from 4,138 patients on sulphonylurea monotherapy, 120 patients on a first-generation drug and 1,537 patients on metformin.
The data showed that the risk of death increased with exposure to sulphonylureas.
However, patients on the highest doses of metformin had a 20 per cent decreased risk of death compared with patients on the lowest doses.
The newer sulphonylurea glyburide (Gliben) was found to be safer than the older drugs. High exposure to glyburide increased mortality by 30 per cent, while high doses of the older drugs chlorpropamide (Diabinese) and tolbutamide (Rastinon) more than doubled it.
Dr Peter Tasker, a GP in Kings Lynn, Norfolk, said that the use of sulphonylureas in the treatment of type-2 diabetes needed to be reviewed. He said: 'The big message is to stop using older sulphonylureas altogether, and where possible use metformin.'
CMAJ 2006; 174(2):169-174