Aspirin (low-dose)

Low-dose aspirin (typically 75–100 mg daily) is an irreversible COX-1 inhibitor that suppresses platelet thromboxane A2, reducing platelet aggregation. It is approved for secondary prevention of myocardial infarction and ischemic stroke, where benefit clearly outweighs bleeding risk. The ASPREE trial in healthy older adults showed no cardiovascular benefit, increased major bleeding, and a signal of increased all-cause mortality. Current guidelines discourage routine primary prevention; the USPSTF 2022 recommends individualized decision-making in adults 40–59 with at least 10 percent 10-year CVD risk and recommends against initiation in adults aged 60 or older. Cancer-prevention signals remain investigational.