PT  - JOURNAL ARTICLE
AU  - Wenjiang Zhang
AU  - Yamini Ramamoorthy
AU  - Tansel Kilicarslan
AU  - Helma Nolte
AU  - Rachel F. Tyndale
AU  - Edward M. Sellers
TI  - Inhibition of Cytochromes P450 by Antifungal Imidazole Derivatives
AID  - 10.1124/dmd.30.3.314
DP  - 2002 Mar 01
TA  - Drug Metabolism and Disposition
PG  - 314--318
VI  - 30
IP  - 3
4099  - http://dmd.aspetjournals.org/content/30/3/314.short
4100  - http://dmd.aspetjournals.org/content/30/3/314.full
SO  - Drug Metab Dispos2002 Mar 01; 30
AB  - The interactions of a panel of antifungal agents with cytochromes P450 (P450s), as a means of predicting potential drug-drug interactions, have not yet been investigated. The objective of this study was to evaluate the specificity and selectivity of five antifungal agents using selective probe reactions for each of the eight major P450s. The index reactions used were phenacetinO-deethylation (for CYP1A2), coumarin 7-hydroxylation (CYP2A6), diclofenac 4′-hydroxylation (CYP2C9), omeprazole 5-hydroxylation (CYP2C19), dextromethorphanO-demethylation (CYP2D6), 7-ethoxy-4-trifluoromethylcoumarin deethylation (CYP2B6), chlorzoxazone 6-hydroxylation (CYP2E1), and omeprazole sulfonation (CYP3A4). Five antifungal agents that include an imidazole moiety (clotrimazole, miconazole, sulconazole, tioconazole, and ketoconazole) were examined in cDNA-expressing microsomes from human lymphoblast cells or human liver microsomes. All inhibitors studied demonstrated nonselective inhibition of P450s. Ketoconazole seemed to be the most selective for CYP3A4, although it also inhibited CYP2C9. High-affinity inhibition was seen for CYP1A2 (sulconazole and tioconazoleKi, 0.4 μM), CYP2B6 (miconazoleKi, 0.05 μM; sulconazoleKi, 0.04 μM), CYP2C19 (miconazoleKi, 0.05 μM; sulconazoleKi, 0.008 μM; tioconazoleKi, 0.04 μM), CYP2C9 (sulconazoleKi, 0.01 μM), CYP2D6 (miconazoleKi, 0.70 μM; sulconazoleKi, 0.40 μM), CYP2E1 (tioconazoleKi, 0.4 μM), and CYP3A4 (clotrimazoleKi, 0.02 μM; miconazoleKi, 0.03 μM; tioconazoleKi, 0.02 μM). Therefore, this class of compounds is likely to result in significant drug-drug interactions in vivo. The American Society for Pharmacology and Experimental Therapeutics