Regulator warns against routine aspirin use for primary prevention
By Lilian Anekwe
GPs are being warned by the drug regulator not to prescribe aspirin outside of its licensed indication for secondary prevention of vascular disease, in a move that looks set to have major implications for current clinical practice.
The MHRA warning comes after its analysis of recent studies of the risks and benefits of aspirin in primary prevention of thrombotic vascular disease concluded the drug's use for primary prevention would not normally be justified.
Both a University of Edinburgh study and a University of Oxford meta recently cast doubt of use of aspirin for primary prevention, finding it had little benefits but carried substantial risks of serious bleeding.
The Scottish Intercollegiate Guidelines Network last month became the first guidance body in the UK to come out against use of aspirin for primary prevention, and the MHRA has now reinforced the impression of a sharp shift in attitudes to the drug.
The MHRA's October Drug and Safety Update warned GPs: ‘Aspirin is licensed for the secondary prevention of vascular events only. It is not licensed for the primary prevention of vascular events.'
The bulletin added: ‘If aspirin is used in primary prevention, the balance of benefits and risks should be considered for each individual, particularly presence of risk factors for vascular disease, including conditions such as diabetes, and risk of gastrointestinal bleeding.'
NICE is due to review its guidance on the prevention of cardiovascular disease in time for updated guidance in May 2011, with some experts calling on it to fast-track that review.
The MHRA warning raises a possible medico-legal risk if GPs continue to prescribe the drug. Dr Stephanie Bown, head of policy at the Medical Protection Society, said: ‘If a drug is not licensed GPs have an additional responsibility to come to a decision with the patient, and be prepared to justify that decision.'
Professor David Fitzmaurice, professor of primary care at the University of Birmingham and a GP in the city, said: ‘People extrapolated from aspirin's validity and use in secondary prevention and have been using it in primary prevention almost as an act of faith.
‘It might seem sensible to use it in people who are at risk but on a population wide level the evidence is not there and there is more and more evidence it does harm. It's surprising we were conned into using it in the first place. We need to disseminate the information that it should not be used in primary prevention of vascular events.'How aspirin fell out of favour
May 2009 – The Antithrombotic Trialists Collaboration from the University of Oxford any vascular benefit of aspirin in primary prevention is likely to be at least partly offset by the increase in bleeds
August 2009 – The Aspirin for Asymptomatic Atherosclerosis trial by a team at the University of Edinburgh finds no significant difference between 3,350 Scottish patients randomised to either aspirin on placebo, but a 71% increase in bleeding require hospital admission
September 2009 – Scottish Intercollegiate Guidelines Network (SIGN) recommend in draft guidance that the use of aspirin in ‘not recommended' for primary prevention in patients with diabetes
October 2009 – MHRA advises GPs that ‘the results of recent studies lend support to the licensed indications for aspirin in secondary prevention of vascular events only'Aspirin's benefit is outweighed by side-effects such as oesophagitis Aspirin's benefit is outweighed by side-effects such as oesophagitis