In the setting of an ACS, the minimum dose of ASA that should be given is 162 mg. Chewing provides antiplatelet effects slightly faster than simply swallowing, though the difference is probably not clinically significant. Enteric coated aspirin, however, clearly takes longer to work and should therefore be avoided in patients with ACS.
A dose of 325 mg does not appear to provide any further benefit beyond the 162 mg dose, though there might be a slightly higher bleeding rate. Despite that the 2005 PCI guidelines recommend a dose of 325 mg as the initial dose for patients with ACS if they are not chronically taking ASA. Otherwise, 162 mg is sufficient.
