Given an abstract from a research paper, your task is to identify and label relationships between chemical compounds and genes mentioned in the abstract.

The relationship type must be one of ['DOWNREGULATOR', 'SUBSTRATE', 'INDIRECT-REGULATOR', 'PART-OF', 'MODULATOR-ACTIVATOR', 'REGULATOR', 'INHIBITOR', 'COFACTOR', 'UPREGULATOR', 'ACTIVATOR', 'ANTAGONIST', 'NOT', 'INDIRECT-DOWNREGULATOR', 'SUBSTRATE_PRODUCT-OF', 'INDIRECT-UPREGULATOR', 'AGONIST', 'PRODUCT-OF', 'MODULATOR', 'DIRECT-REGULATOR', 'UNDEFINED', 'AGONIST-INHIBITOR', 'AGONIST-ACTIVATOR', 'MODULATOR-INHIBITOR'].

Please format your output as a JSON array. Each entry in the array should express a single relation, formatted as ["<Entity_A>", "<RELATION_A_B>", "<Entity_B>"]. If no relations can be found, please output an empty JSON array [].

Abstract:

Role of cytochrome P4502B6 in methadone metabolism and clearance. Methadone N-demethylation in vitro is catalyzed by hepatic cytochrome P4502B6 (CYP2B6) and CYP3A4, but clinical disposition is often attributed to CYP3A4. This investigation tested the hypothesis that CYP2B6 is a prominent CYP isoform responsible for clinical methadone N-demethylation and clearance, using the in vivo mechanism-based CYP2B6 inhibitor ticlopidine, given orally for 4 days. A preliminary clinical investigation with the CYP3A4/5 substrate probe alfentanil established that ticlopidine did not inhibit intestinal or hepatic CYP3A4/5. Subjects received intravenous plus oral (deuterium-labeled) racemic methadone before and after ticlopidine. Ticlopidine significantly and stereoselectively (S   >   R) inhibited methadone N-demethylation, decreasing plasma metabolite/methadone area under the curve ratios and metabolite formation clearances. Ticlopidine also significantly increased the dose-adjusted plasma area under the curve for R- and S-methadone by 20% and 60%, respectively, after both intravenous and oral dosing. CYP2B6 inhibition reduces methadone N-demethylation and clearance, and alters methadone concentrations, demonstrating an important role for CYP2B6 in clinical methadone disposition.
[["methadone", "SUBSTRATE", "CYP2B6"], ["methadone", "SUBSTRATE", "CYP"], ["Methadone", "SUBSTRATE", "cytochrome P4502B6"], ["Methadone", "SUBSTRATE", "CYP2B6"], ["ticlopidine", "INHIBITOR", "CYP2B6"], ["Methadone", "SUBSTRATE", "CYP3A4"]]