Acetylsalicylic acid
Acetylsalicylic acid is a salicylate that blocks cyclooxygenase irreversibly. In platelets that block lasts for the whole life of the platelet, so they clump less readily and blood clots form less easily; the same enzyme block also relieves pain and fever. It is used for pain and fever, and, at the strengths meant for the blood, to prevent clots and strokes in people at raised risk.
It is taken with food, because the enzyme it blocks also maintains part of the stomach's own protection, and bleeding there is the main hazard. Alcohol, prednisolone and ibuprofen all add to that risk, and ibuprofen can additionally get in the way of the antiplatelet effect. Clopidogrel and omega-3 supplements lengthen bleeding further, and it is not combined with warfarin, rivaroxaban, apixaban or ketorolac. Hemoglobin, platelets and ferritin are the values worth following, since quiet blood loss is the usual reason iron stores fall while it is being used.
Bleeding that will not stop, black or tarry stools, coffee-ground vomit, unexplained bruising, or steadily growing tiredness and pallor mean see a doctor. When it has been prescribed to prevent clots, that course is not interrupted on one's own, even after a bleeding scare — the decision belongs with the doctor.
Reference information, not medical advice. Discuss any change with your doctor.