• Aspirin (300 mg daily) should be started immediately, unless it is contraindicated or not tolerated, and continued at this dose until reviewed in secondary care:
• Do not delay initiating aspirin treatment in people with uncontrolled blood pressure.
• Consider gastroprotection (e.g. a proton pump inhibitor) if the person is at high risk of adverse gastrointestinal effects or experiences aspirin-induced dyspepsia.
• Consider clopidogrel (75 mg daily — off-label use) only if the person is allergic or cannot tolerate aspirin.
• Both aspirin and clopidogrel are contraindicated in people with active gastrointestinal bleeding or ulceration.
• For further information on antiplatelet therapy (including managing gastrointestinal issues), see the CKS topic on Antiplatelet treatment.
• For people who are already prescribed low-dose aspirin:
• Continue the current dose of aspirin until reviewed in secondary care.
• If non-compliance is suspected, start aspirin 300 mg daily immediately (see above).
• Check for unrecognized risk factors for transient ischaemic attack, such as atrial fibrillation (for more information, see the CKS topic on Atrial fibrillation).
• For people who have a transient ischaemic attack while on warfarin:
• Admit immediately for an urgent brain scan to exclude haemorrhagic stroke.
• Other measures for secondary prevention should be introduced as soon as the diagnosis is confirmed.

These recommendations are in line with guidelines issued by the Department of Health, the National Institute for Health and Clinical Excellence (NICE), and the Royal College of Physicians Intercollegiate Stroke Working Party (RCP ICSWP) [Intercollegiate Stroke Working Party, 2008; National Collaborating Centre for Chronic Conditions, 2008; NICE, 2010b].

Rationale for giving aspirin

• The recommendation to offer immediate aspirin (300 mg) to people who have possibly had a transient ischaemic attack (TIA) is based on the National Stroke Strategy issued by the Department of Health [DH, 2007] and evidence showing that early initiation of treatment (including aspirin) was associated with an 80% reduction in the risk of early recurrent stroke in people with a TIA or minor stroke [Rothwell et al, 2007]:
• Aspirin is given after a TIA to reduce the risk of subsequent stroke.
• Unlike in people with acute ischaemic stroke, the risk that aspirin will provoke or aggravate intracerebral bleeding is low after a TIA.

For people with uncontrolled blood pressure who develop a TIA

• CKS did not identify any evidence for withholding aspirin in people with uncontrolled blood pressure who develop a TIA.
• Feedback from expert reviewers recommended that aspirin treatment should not be delayed in these people.

For people who require an antiplatelet drug and are intolerant of aspirin

• The NICE Guideline Development Group found little evidence to guide the management of people who develop a TIA who are intolerant of aspirin.
• The consensus of the Guideline Development Group (based on their clinical experience) was that people should take aspirin (with proton pump inhibitor cover where appropriate) unless there are absolute contraindications, such as true allergy to aspirin.
• The recommendation to offer clopidogrel (off-label use) to people intolerant of aspirin is in line with guidance issued by the RCP ICSWP [Intercollegiate Stroke Working Party, 2008].

Dosage of clopidogrel for people in whom aspirin is contraindicated

• There is uncertainty regarding whether a loading dose of 300 mg should be given (followed by 75 mg daily) in people with TIA:
• Although a loading dose is licensed for people with acute coronary syndrome, the use of clopidogrel immediately after a TIA is unlicensed.
• National guidelines provide no recommendation regarding dosage [SIGN, 2002; Intercollegiate Stroke Working Party, 2008; National Collaborating Centre for Chronic Conditions, 2008]. The NICE Technology Appraisal on clopidogrel does not cover unlicensed uses [NICE, 2005a].
• Feedback from expert reviewers was divided and highlighted an uncertainty as to whether a loading dose is required. Although a loading dose was used in the EXPRESS study [Rothwell et al, 2007], it was acknowledged among expert reviewers that there is no good evidence to support this.
• Given the uncertainty, the unlicensed status of clopidogrel in TIA, and lack of evidence for the use of loading dose after TIA, CKS recommends initiating clopidogrel at 75 mg daily until further evidence or guidance indicates otherwise.

For people who develop a TIA and are already taking aspirin

• CKS did not identify any evidence on what to do when TIA occurs in a person already taking aspirin.
• The recommendation to maintain the current aspirin dose is in line with guidance issued by the American Heart Association and American Stroke Association Council on Stroke, which is based on expert opinion [Sacco et al, 2006]. They found no evidence on:
• Increasing the dose of aspirin.
• Alternative antiplatelet drugs.
• Combinations of antiplatelet drugs.
• Feedback from expert reviewers generally recommended that the current dose of aspirin should be continued in people who develop TIA and are already prescribed low-dose aspirin.

For people on an anticoagulant who develop a TIA

• The recommendation for immediate admission for brain imaging to exclude haemorrhagic stroke is based on the consensus opinion of the RCP ICSWP [Intercollegiate Stroke Working Party, 2008].