ASPIRIN AND LOW-MOLECULAR-WEIGHT HEPARINS

Although the concurrent use of aspirin and heparin is effective in the prevention of post-operative thromboembolism, the risk of bleeding in patients receiving heparin is increased almost 2.5-fold by the use of aspirin. Cases of retroperitoneal and spinal haematoma have been reported with concurrent use of low-molecular-weight heparins (e.g. enoxaparin) and aspirin.
Unless specifically indicated, such as in unstable angina, it may be prudent to avoid the combined use of aspirin with LMWHs because of the likely increased risk of bleeding. Patients should be monitored closely for signs of bleeding.