PF-04457845 is a potent, orally active, irreversible inhibitor of fatty acid amide hydrolase (FAAH), the principle enzyme involved in the degradation of the endocannabinoid anandamide. PF-04457845 is a covalent inhibitor that carbamylates FAAH′s serine nucleophile. It was shown to be both potent and selective against other serine hydrolases. It has an IC50 value of 7.2 nM for human FAAH. The endocannabinoid system is a target for therapeutic pain relief. In a rat model of inflammatory pain, PF-04457845 produced significant reduction of inflammatory pain with efficacy comparable to that of naproxen at 10 mg/kg.
