Aspirin Interactions

Aspirin (and other salicylates) displace valproate from plasma albumin binding sites and also inhibit valproate's beta-oxidation, leading to increases in the free (active) valproate fraction by up to fourfold. Even total valproate levels may not rise dramatically, masking the increase in pharmacologically active free drug and raising the risk of valproate toxicity (sedation, tremor, hyperammonemia, hepatotoxicity).

Alcohol and aspirin together significantly increase the risk of gastrointestinal bleeding because aspirin irreversibly inhibits platelets for their entire 7-10 day lifespan while alcohol damages the gastric lining and impairs clot formation. The risk is particularly elevated for daily low-dose aspirin users who drink regularly.

Ginkgo biloba can inhibit platelet-activating factor (PAF) and platelet aggregation, which can add to aspirin's irreversible inhibition of cyclooxygenase-1 and thromboxane A2. The combination may modestly increase minor bleeding events, with case reports of more serious bleeds in vulnerable patients.

Omega-3 fatty acids in fish oil reduce platelet aggregation and prolong bleeding time slightly, theoretically adding to aspirin's antiplatelet effect. Clinical trials, however, consistently show no clinically significant increase in major bleeding even with high-dose fish oil added to aspirin.