The primary side effect associated with aspirin use is increased bleeding. Aspirin works as an antiplatelet agent by inhibiting the production of thromboxane A2, a substance that promotes platelet aggregation. This inhibition reduces the ability of platelets to stick together, which is beneficial in preventing heart attacks and strokes. However, this antiplatelet effect can lead to an increased risk of bleeding, including gastrointestinal bleeding, excessive bruising, or prolonged bleeding from cuts.
While gastrointestinal upset is a common concern with aspirin use, it is not the most significant side effect compared to the risk of bleeding. Headaches may occur as a result of other factors but are not directly tied to aspirin. Similarly, skin rashes can happen but are considered less frequent and not a primary or concerning effect when assessing the side effects of aspirin compared to the risk of increased bleeding.