For the secondary prevention of stroke following non-cardioembolic TIA or stroke, combination treatment with dipyridamole
(as the extended release formulation) and low dose aspirin has been shown to produce more benefit than aspirin alone.
Most of the evidence comes from two trials; ESPS-2 and ESPRIT.
In ESPS-2, the stroke rate at 24 months follow up was significantly reduced in the aspirin plus dipyridamole group compared
with aspirin alone (absolute risk reduction 3%).
In the ESPRIT trial, death from all vascular causes, non-fatal stroke, non-fatal MI, or major bleeding complication
after a mean follow-up of 3.5 years, was significantly lower in the combination group compared with aspirin alone (absolute
risk reduction 1% per year).
Therefore there is considerable debate about the cost effectiveness of adding dipyridamole to aspirin for these indications
and some experts still consider that aspirin alone should remain the first line treatment. However most current international
guidelines recommend aspirin plus dipyridamole (or clopidogrel monotherapy in aspirin allergic patients) as the preferred
Aspirin plus dipyridamole is recommended for up to two years after the most recent ischaemic event. After this time
aspirin alone can be used (unless there are ongoing ischaemic events).21
Currently dipyridamole is only subsidised if a person continues to have TIAs whilst taking aspirin or is aspirin intolerant
(aspirin induced asthma, urticaria, anaphylaxis, or significant aspirin induced bleeding excluding bruising). This restriction
is currently under review.
Dipyridamole is also available on special authority for use in patients who have prosthetic heart valves and after CABG
Dipyridamole can cause a range of unpleasant adverse effects. Effects such headache, dizziness, nausea and diarrhoea
may occur but are usually short lived and most patients can persevere with treatment. Rarely symptoms of ischaemic heart
disease, particularly angina, can become worse with dipyridamole use. Dipyridamole should therefore be used cautiously
in people with severe coronary artery disease including unstable angina, recent MI and heart failure. It may also exacerbate
migraine, postural hypotension and myasthenia gravis.