CYP2C9

CYP2C9 is a key CYP450 isoform that metabolises warfarin, phenytoin, losartan, and several NSAIDs. Cannabinoid-mediated inhibition of CYP2C9 can raise warfarin levels significantly, increasing bleeding risk — which is why co-prescription mandates more frequent INR monitoring and, often, prophylactic warfarin dose-reduction at cannabinoid initiation.

Related terms

• CYP450Family of liver enzymes that metabolise many drugs, including cannabinoids — source of many clinically relevant interactions.
• CYP3A4Most abundant hepatic CYP450 isoform; affected by both THC and CBD.