Aspirin Interactions

Aspirin and other salicylates push valproate off its plasma-protein binding sites and slow one of its breakdown pathways, so the active, unbound portion of valproate can rise even when the standard total valproate blood level looks unchanged. This can mask a clinically meaningful increase in active drug and raise the risk of valproate toxicity such as sedation, tremor, confusion, raised ammonia, and liver strain, while aspirin's own anti-clotting effect adds to valproate's tendency to lower platelets.

Aspirin and alcohol both damage the gastric lining and impair clotting; used together they raise the risk of upper gastrointestinal bleeding, with risk rising as alcohol intake and aspirin use increase.

Ginkgo biloba can inhibit platelet-activating factor (PAF) and platelet aggregation, which may add to aspirin's irreversible inhibition of cyclooxygenase-1 and thromboxane A2. Observational data suggest a modest increase in minor bleeding events when the two are combined, and there are case reports of more serious bleeds in vulnerable patients, though a controlled trial found no measurable added effect on platelet function.

Omega-3 fatty acids in fish oil mildly reduce platelet aggregation, which in theory adds to aspirin's antiplatelet effect. In practice, clinical studies have not found a clinically significant increase in major bleeding when standard fish oil is combined with aspirin.