Final answer:
Phenylbutazone affects coagulation primarily by displacing warfarin from its albumin binding sites, increasing warfarin’s active concentration in blood and enhancing its anticoagulant effects. It may also interact with aspirin which affects platelet function.
Step-by-step explanation:
The effect of Phenylbutazone on the coagulation system is primarily through binding to albumin, displacing warfarin. This displacement leads to an increased effect of warfarin because it increases the warfarin concentration in the blood. Warfarin is a well-known anticoagulant that functions by inhibiting the synthesis of vitamin K-dependent clotting factors within the liver, which are essential for blood clotting. So, altering warfarin’s binding to albumin can significantly affect its anticoagulant activity. Phenylbutazone may also interact with aspirin, another anticoagulant that works by inhibiting the platelets' ability to clump together and form a clot. Specifically, aspirin blocks the formation of thromboxane A2 (TXA2), a potent agent that promotes platelet aggregation.