Increased liver enzymes and hepatic failure have been associated with the use of dipyridamole. Aspirin should be avoided in severe hepatic disease. Information on drug interactions is provided from existing literature on the individual constituents contained in this product. Interactions with aspirin are mostly a result of either protein binding displacement or inhibitory prostaglandin effects. Increased effects of methotrexate, warfarin, heparin, acetazolamide, and oral hypoglycemics can occur when administered with aspirin.
Alcohol can increase the risk of gastrointestinal bleeding when administered with aspirin.
Aggrenox contains two agents that work by different mechanisms to inhibit platelet aggregation. Aspirin inhibits platelet aggregation through irreversible inhibition of platelet cyclo-oxygenase. This prevents the formation of the platelet-aggregating substance thromboxane A2. Dipyridamole inhibits the uptake of adenosine into platelets, endothelial cells, and erythrocytes. Dipyridamole also inhibits phosphodiesterase and this can result in vasodilation.