Sulfaphenazole and α-naphthoflavone attenuate the metabolism of the synthetic cannabinoids JWH-018 and AM2201 found in K2/spice.

"K2" or "Spice" is an emerging drug of abuse that is laced with psychoactive synthetic cannabinoids JWH-018 and AM2201. Previous studies have identified hydroxylated (OH) and carboxylated (COOH) species as primary human metabolites, and kinetic studies have implicated CYP2C9 and -1A2 as major hepatic P450s involved in JWH-018 and AM2201 oxidation. The present study extends these findings by testing the hypothesis that CYP2C9- and 1A2-selective chemical inhibitors, sulfaphenazole (SFZ) and α-naphthoflavone (ANF), block oxidation of JWH-018 and AM2201 in human liver microsomes (HLM). A concentration-dependent inhibition of JWH-018 and AM2201 oxidation was observed in the presence of increasing concentration of SFZ (0.5 - 50 μM) and ANF (0.1 - 5.0 μM). No metabolic inhibition was observed with omeprazole, quinidine, and ketoconazole. The results presented herein further demonstrate the importance of CYP2C9- and 1A2-mediated oxidation of JWH-018 and AM2201 and the likelihood of adverse toxicity in populations with polymorphic alleles of these enzymes.