Answer
Mr Chu was advised to cease using Aspirin for pain control because he was to have a hip replacement surgery, soon. It is known that aspirin inhibits platelet aggregation, and therefore delays coagulation. If he was to continue taking aspirin close to the time of surgery, it would increase the risk of prolonged, life-threatening post-surgical bleeding .
Mr Chu was in pain and he would be in pain for some time after his surgical operation. Therefore, he needed to take an analgesic drug daily. Before surgery he was accustomed to take aspirin for pain relief. The doctor suggested that he replace Aspirin with Acetominophen before having his surgery. The doctor considered this a safer drug because Acetominophen does not inhibit Thromboxane A2 action, and consequently does not affect platelet aggregation and clotting time.
Work Step by Step
Most surgeons would require a patient to cease use of aspirin for at least seven days before any surgical operation. This is a precaution to reduce the risk of life-threatening post-surgical bleeding. For a patient who is in pain before surgery , some alternative non-opioid medications are Naprosyn, Ibupropfen , Ketorolac, and Acetominophen (Paraceamol). In this group, all of the other analgesics (NSAIDs) except Acetominophen(Tylenol) have been shown to have some minor effects on the coagulation process. However, Acetominophen at normal analgesic doses ( in acute treatment of pain) does not inhibit the action of Thromboxane A2 ;therefore, it does not impair platelet the aggregation process, nor decrease clotting time. It is therefore a safe analgesic to use (acutely) before surgery
Aspirin affects coagulation because it has a negative impact of the production of Thromboxane A2.
Thromboxane A2 is produced by platelets. One of the effects of aspirin is to inhibit the cyclooxegenase enzyme which is important in the synthesis of prostaglandins and Thromboxane A2.. Thromboxane A2 is required for platelet aggregation, formation of the platelet plug, and for formation blood clots. Aspirin taken close to the time of a surgical operation ( not after eight days before surgery) places the patient at great risk of prolonged , life-threatening bleeding.
It should be stated that large doses of Acetominophen taken chronically, can impair liver function (are hepatotoxic). When the liver is damaged, its ability to produce erythropoietic factors is impaired. So Acetominophen is not an innocuous drug: it can have negative effects on erythropoiesis and hemostasis.
In Mr Chu's circumstances , acetominophen is a much safer analgesic choice than aspirin.
