Figures obtained from the NHS Prescribing Pricing Division under the Freedom of Information Act show that the number of prescriptions by GPs in England for rosiglitazone fell by 36 per cent between July 2007 and June 2008.
Doubts over the type-2 diabetes drug were first raised in May last year, when US research found it was associated with a 63 per cent increased risk of death from a cardiovascular cause. Current NICE type-2 diabetes guidance continues to recommend the drug.
But the figures obtained by GP show monthly prescribing of rosiglitazone decreased from 117,214 prescriptions in July 2007 to 75,499 in June 2008.
This is in stark contrast to pioglitazone prescribing, which has increased over the same period by 44 per cent.
Between July 2007 and June 2008, monthly prescribing of pioglitazone increased from 53,091 to 76,495. It is now the most commonly prescribed glitazone in England.
Dr Mark Hadley-Brown, chairman of the Primary Care Diabetes Society (PCDS) and a Norfolk GP, said fears that rosiglitazone might increase cardiovascular risk were to blame for the slump in prescribing.
'I am not surprised by the tendency of GPs to use pioglitazone in preference to rosiglitazone.
'If in doubt, and there is genuine doubt, we're going to play safe for our patients.'
Dr Brian Karet, diabetes lead for Bradford PCT, said safety warnings on rosiglitazone packaging had prompted GPs to stop prescribing the drug.
A spokeswoman for GSK, the manufacturer of rosiglitazone (Avandia), said: 'GSK stands firmly behind the safety profile of Avandia when used according to its label, and we believe its benefits continue to outweigh any treatment risks.'
Prescribing switch: 36% - decrease in rosiglitazone prescribing
Source: NHS Prescribing Pricing Division.