Cytochrome P-450 CYP2D6

Publication Title: 
Journal of Ethnopharmacology

ETHNOPHARMACOLOGICAL RELEVANCE: 'Triphala' is one of the age-old, most commonly used polyherbal preparation from Ayurveda as Rasayana drug. AIM OF THE STUDY: This study was aimed at evaluating the effect of 'Triphala' on drug modulating enzymes to assess its safety through its potential to interact with co-administered drugs. MATERIALS AND METHODS: The cytochrome P450 inhibitory effect of 'triphala' formulation was investigated on rat liver microsomes using CYP450-CO complex assay and on individual isoform such as CYP3A4 and 2D6 using fluorescence screening.

Author(s): 
Ponnusankar, S.
Pandit, Subrata
Babu, Ramesh
Bandyopadhyay, Arun
Mukherjee, Pulok K.
Publication Title: 
Drug Metabolism and Disposition: The Biological Fate of Chemicals

Siberian ginseng ([SG]; Eleutherococcus senticosus) is a commonly used herbal preparation. The objective of this study was to assess in normal volunteers (n = 12) the influence of a standardized SG extract on the activity of cytochrome P450 CYP2D6 and 3A4. Probe substrates dextromethorphan (CYP2D6 activity) and alprazolam (CYP3A4 activity) were administered orally at baseline and again following treatment with SG (1 x 485 mg twice daily) for 14 days.

Author(s): 
Donovan, Jennifer L.
DeVane, C. Lindsay
Chavin, Kenneth D.
Taylor, Robin M.
Markowitz, John S.
Publication Title: 
British Journal of Clinical Pharmacology

AIMS: The purpose of this research was to characterize CYP2D6, GST-M1 and GST-T1 enzyme expression in human parathyroid tissue, and to determine whether or not there is any association between deficiencies in these enzymes and serum parathyroid hormone concentrations in patients with end-stage renal disease. METHODS: Surgical human parathyroid tissue was obtained and evaluated by immunohistochemistry for cellular localization of CYP2D6, GST-M1 and GST-T1 and colocalization of CYP2D6 with parathyroid hormone.

Author(s): 
Yan, Feng-Xiang
Langub, M. Chris
Ihnen, Mark A.
Hornung, Carlton
Juronen, Erkki
Rayens, Mary K.
Cai, Wei-Min
Wedlund, Peter J.
Fanti, Paolo
Publication Title: 
Drug Metabolism and Disposition: The Biological Fate of Chemicals

Oxycodone undergoes N-demethylation to noroxycodone and O-demethylation to oxymorphone. The cytochrome P450 (P450) isoforms capable of mediating the oxidation of oxycodone to oxymorphone and noroxycodone were identified using a panel of recombinant human P450s. CYP3A4 and CYP3A5 displayed the highest activity for oxycodone N-demethylation; intrinsic clearance for CYP3A5 was slightly higher than that for CYP3A4. CYP2D6 had the highest activity for O-demethylation. Multienzyme, Michaelis-Menten kinetics were observed for both oxidative reactions in microsomes prepared from five human livers.

Author(s): 
Lalovic, Bojan
Phillips, Brian
Risler, Linda L.
Howald, William
Shen, Danny D.
Publication Title: 
Drug Metabolism and Disposition: The Biological Fate of Chemicals

Green tea extract is a widely used dietary supplement. The objective of this study was to assess the influence of a decaffeinated green tea (DGT; Camellia sinensis) extract on the activity of the drug-metabolizing enzymes cytochrome P-450 2D6 and 3A4. Probe drugs dextromethorphan (30 mg, CYP2D6 activity) and alprazolam (ALPZ; 2 mg, CYP3A4 activity) were administered orally to healthy volunteers (n = 11) at baseline, and again after treatment with four DGT capsules/day for 14 days. Each DGT capsule contained 211 +/- 25 mg of green tea catechins and <1 mg of caffeine.

Author(s): 
Donovan, Jennifer L.
Chavin, Kenneth D.
DeVane, C. Lindsay
Taylor, Robin M.
Wang, Jun-Sheng
Ruan, Ying
Markowitz, John S.
Publication Title: 
Drug Metabolism and Disposition: The Biological Fate of Chemicals

Valerian (Valeriana officinalis) is a popular dietary supplement. The objective of this study was to assess the influence of a valerian extract on the activity of the drug-metabolizing enzymes cytochrome P450 2D6 (CYP2D6) and 3A4. Probe drugs dextromethorphan (30 mg; CYP2D6 activity) and alprazolam (2 mg; CYP3A4 activity) were administered orally to healthy volunteers (n = 12) at baseline and again after exposure to two 500-mg valerian tablets (1000 mg) nightly for 14 days. The valerian supplement contained a total valerenic acid content of 5.51 mg/tablet.

Author(s): 
Donovan, Jennifer L.
DeVane, C. Lindsay
Chavin, Kenneth D.
Wang, Jun-Sheng
Gibson, Bryan B.
Gefroh, Holly A.
Markowitz, John S.
Publication Title: 
Drug Metabolism and Disposition: The Biological Fate of Chemicals

Members of the cytochrome P450 (P450) enzyme families CYP1, CYP2, and CYP3 are responsible for the metabolism of approximately 75% of all clinically relevant drugs. With the increased prevalence of nonalcoholic fatty liver disease (NAFLD), it is likely that patients with this disease represent an emerging population at significant risk for alterations in these important drug-metabolizing enzymes. The purpose of this study was to determine whether three progressive stages of human NALFD alter hepatic P450 expression and activity.

Author(s): 
Fisher, Craig D.
Lickteig, Andrew J.
Augustine, Lisa M.
Ranger-Moore, James
Jackson, Jonathan P.
Ferguson, Stephen S.
Cherrington, Nathan J.
Publication Title: 
Pediatric Emergency Care

BACKGROUND: Pain is the most common reason for seeking health care in the Western world and is a contributing factor in up to 80% of all emergency department (ED) visits. In the pediatric emergency setting, musculoskeletal injuries are one of the most common painful presentations. Inadequate pain management during medical care, especially among very young children, can have numerous detrimental effects. No standard of care exists for the management of acute musculoskeletal injury-related pain in children.

Author(s): 
Ali, Samina
Drendel, Amy L.
Kircher, Janeva
Beno, Suzanne
Publication Title: 
Journal of Pharmacy & Pharmaceutical Sciences: A Publication of the Canadian Society for Pharmaceutical Sciences, Société Canadienne Des Sciences Pharmaceutiques

PURPOSE: Traditional Chinese medicines (TCM) are believed by many to be safe and used for self-medication without supervision. Although the risk appears to be low, certain TCM have been associated with a number of serious adverse reactions. A preliminary study was undertaken with 12 products using a human cytochrome P450 (CYP450) isozyme assay to determine if these products could affect human drug metabolism.

Author(s): 
Foster, Brian C.
Vandenhoek, Susan
Tang, Rainy
Budzinski, Jason W.
Krantis, Anthony
Li, K. Y.
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