COX

COX-1

Cyclooxygenase 1

Also known as: COX-1, COX1, PTGS1

What it is

Constitutive enzyme that produces prostaglandins with protective functions: maintains the gastric mucosa, regulates platelet aggregation (thromboxane A2) and renal flow.

Role in interactions

COX-1 inhibition by NSAIDs and aspirin explains the gastrotoxic effects (ulcer, bleeding) and, with aspirin, the antiplatelet effect. It is the target of NSAID + anticoagulant/antiplatelet interactions.

Common substrates3

arachidonic acid (yields PGE2PGI2thromboxane A2)

Inhibitors7

aspirin (irreversiblelow doses)diclofenac ibuprofen naproxen ketorolac indomethacin

Inducers1

not applicable (no clinically relevant inducers)

Clinical notes

COX-1 inhibition is the mechanism of additive bleeding risk when NSAIDs/aspirin are combined with oral anticoagulants or antiplatelets.