Effects of various factors including the CYP2D6 genotype and coadministration of flunitrazepam on the steady-state plasma concentrations of bromperidol and its reduced metabolite

1998 ◽  
Vol 135 (4) ◽  
pp. 333-337 ◽  
Author(s):  
A. Suzuki ◽  
K. Otani ◽  
K. Mihara ◽  
N. Yasui ◽  
T. Kondo ◽  
...  
Keyword(s):  
Steady State ◽  
Plasma Concentrations ◽  
Cyp2d6 Genotype ◽  
State Plasma

CYP2D6 genotypes in association with steady state plasma concentrations of active metabolites of tamoxifen in patients with breast cancer

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 634-634 ◽  
Author(s):  
H. Lim ◽  
H. Lee ◽  
K. Lee ◽  
E. Lee ◽  
I. Jang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Steady State ◽  
Plasma Concentrations ◽  
Cancer Center ◽  
Cyp2d6 Genotype ◽  
Active Metabolites ◽  
Fluorescence Detector ◽  
Wilcoxon Rank Sum Test ◽  
Center Hospital ◽  
State Plasma

634 Background: Tamoxifen is a prodrug that is metabolized to active metabolites, Z-4-hydroxy-N-desmethyltamoxifen (BX) and Z-4-hydroxy-tamoxifen (4OH) where CYP2D6 plays a major role in the conversion. Genetic polymorphisms of CYP2D6 by ethnicities are well known with CYP2D6*10 in Asians (up to 50% in Koreans), and CYP2D6 *2 and *4 in American Whites as major variant alleles. We analyzed the steady state plasma concentrations of tamoxifen and its metabolites in patients (pts) with breast cancer to evaluate their associations with various CYP2D6 genotypes. Methods: Blood samples were collected from 219 pts on tamoxifen, 20 mg daily as adjuvant therapy for more than 3 months at National Cancer Center, Korea. Plasma tamoxifen, N-desmethyltamoxifen, BX, 4OH were measured by validated HPLC with fluorescence detector, and analyzed according to CYP2D6 genotype groups by Wilcoxon rank sum test. CYP2D6*10, CYP2D6*5 and CYP2D6*2×2 were identified by PCR-RFLP methods, and the rests were classified as CYP2D6*1 (wild type). This study was approved by IRB at National Cancer Center Hospital (NCCNHS04–033) and conducted after informed consent obtained by the patients. Results: Thus far, we measured plasma concentration of tamoxifen and its metabolites for 158 pts among 198 pts genotyped. 59 pts (29.8%) carried CYP2D6*1/*1, 84 pts (42.4%) *1/*10 and 49 pts (24.7%) *10/*10. Other types were CYP2D6*1/*5 (8.6%), *5/*5 (1.0%), *1/*2×2 (2.5%). Pts with CYP2D6 *10/*10 (n=40) demonstrated significantly lower steady state plasma concentrations of BX and 4OH than those with other genotypes (n=118) (BX: 7.9 vs.19.2. ng/ml [95 % CI; 5.5–10.4 vs. 15.8–22.7 ng/ml] p<0.0001; 4OH: 1.5 vs. 2.8 ng/ml [95 % CI; 1.1–2.0 vs. 2.3–3.3 ng/ml] p<0.0001), whereas there were no differences with *1/*10 (n=64) vs. without *10 allele (n=54) (BX: 20.6 vs. 18.1 ng/ml; 4OH: 2.9 vs. 2.7 ng/ml). Basically no significant differences in BX/4OH or other compounds by various CYP2D6*2 ×2 and *5 alleles were observed. Conclusions: The steady state plasma concentrations of BX and 4OH were significantly low with CYP2D6 *10/*10 genotype, and their clinical implications need to be explored.(Supported by a grant NCC-0410590). No significant financial relationships to disclose.

Clinical Implications of CYP2D6 Genotypes Predictive of Tamoxifen Pharmacokinetics in Metastatic Breast Cancer

2007 ◽  
Vol 25 (25) ◽  
pp. 3837-3845 ◽  
Author(s):  
Hyeong-Seok Lim ◽  
Han Ju Lee ◽  
Keun Seok Lee ◽  
Eun Sook Lee ◽  
In-Jin Jang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Steady State ◽  
Clinical Outcome ◽  
Plasma Concentrations ◽  
Metastatic Breast ◽  
Pregnane X Receptor ◽  
Cyp2d6 Genotype ◽  
Breast Cancer Patients ◽  
State Plasma

Purpose The CYP3A and CYP2D6 enzymes play a major role in converting tamoxifen to its active metabolites. CYP3A is a highly inducible enzyme, regulated mainly by pregnane X receptor (PXR). This study assessed the association between genetic polymorphisms of CYP2D6 and PXR, and tamoxifen pharmacokinetics (PK) and clinical outcomes in patients with breast cancer. Patients and Methods Plasma concentrations of tamoxifen and its metabolites were measured. Common alleles of CYP2D6 and PXR were identified in 202 patients treated with tamoxifen 20 mg daily for more than 8 weeks. Twelve of the 202 patients and an additional nine patients with metastatic breast cancer receiving tamoxifen were assessed for clinical outcome in correlation with genotypes. Results Patients carrying CYP2D6*10/*10 (n = 49) demonstrated significantly lower steady-state plasma concentrations of 4-hydroxy-N-desmethyltamoxifen and 4-hydroxytamoxifen than did those with other genotypes (n = 153; 4-hydroxy-N-desmethyltamoxifen: 7.9 v 18.9 ng/mL, P < .0001; 4-hydroxytamoxifen: 1.5 v 2.6 ng/mL, P < .0001), whereas no difference by PXR genotypes was found. CYP2D6*10/*10 was significantly more frequent among nonresponders with MBC (100% v 50%, P = .0186). In Cox proportional hazard analysis, CYP2D6 genotype and number of disease sites were significant factors affecting time to progression (TTP). The median TTP for patients receiving tamoxifen was shorter in those carrying CYP2D6*10/*10 than for others (5.0 v 21.8 months, P = .0032) Conclusion CYP2D6*10/*10 is associated with lower steady-state plasma concentrations of active tamoxifen metabolites, which could possibly influence the clinical outcome by tamoxifen in Asian breast cancer patients.

Relationship between the CYP2D6 genotype and the steady-state plasma concentrations of trazodone and its active metabolite m -chlorophenylpiperazine

1997 ◽  
Vol 133 (1) ◽  
pp. 95-98 ◽  
Author(s):  
Kazuo Mihara ◽  
K. Otani ◽  
Akihito Suzuki ◽  
Norio Yasui ◽  
Hajime Nakano ◽  
...  
Keyword(s):  
Steady State ◽  
Active Metabolite ◽  
Plasma Concentrations ◽  
Cyp2d6 Genotype ◽  
State Plasma

CYP2D6 genotype and steady-state plasma concentrations (Css) of haloperidol

1998 ◽  
Vol 13 (1) ◽  
pp. 45
Author(s):  
A. Suzuki ◽  
K. Mihara ◽  
N. Yasui ◽  
T. Kondo ◽  
S. Kaneko ◽  
...  
Keyword(s):  
Steady State ◽  
Plasma Concentrations ◽  
Cyp2d6 Genotype ◽  
State Plasma

scholarly journals Fasting Remnant Lipoprotein Cholesterol and Triglyceride Concentrations Are Elevated in Nondiabetic, Insulin-Resistant, Female Volunteers1

1999 ◽  
Vol 84 (11) ◽  
pp. 3903-3906 ◽  
Author(s):  
Fahim Abbasi ◽  
Tracey McLaughlin ◽  
Cindy Lamendola ◽  
Helen Yeni-Komshian ◽  
Akira Tanaka ◽  
...  
Keyword(s):  
Steady State ◽  
Plasma Concentrations ◽  
Lipoprotein Metabolism ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Insulin Resistant ◽  
Remnant Lipoprotein ◽  
Increased Risk ◽  
Resistant Group ◽  
State Plasma

This study was initiated to test the hypothesis that plasma concentrations of remnant lipoproteins would be higher after an overnight fast in insulin-resistant compared to insulin-sensitive volunteers. Forty-three healthy nonobese women were studied, divided into insulin-resistant (n = 21) and insulin-sensitive (n = 22) groups on the basis of their steady state plasma glucose (SSPG) concentration at the end of a 180-min infusion of octreotide acetate, insulin, and glucose. Under these conditions, steady state plasma insulin concentrations are similar in all subjects (∼60μ U/mL), and the higher the SSPG concentrations, the more insulin resistant the individual. By selection, mean (±sem) SSPG concentrations were significantly higher (P &lt; 0.001) in the insulin-resistant group (210 ± 7 vs. 78 ± 3 mg/dL). In addition, the insulin-resistant group had higher triglycerides (198 ± 27 vs. 101 ± 12 mg/dL; P &lt; 0.005) and lower high density lipoprotein cholesterol (48 ± 4 vs. 60 ± 4 mg/dL; P &lt; 0.05) concentrations. Finally, insulin resistance was associated with higher remnant lipoprotein particle concentrations of cholesterol (7.2 ± 0.8 vs. 4.4 ± 0.3; P &lt; 0.005) and triglycerides (22.2 ± 3.4 vs. 8.5 ± 1.0; P &lt; 0.001). All of these differences were seen despite the fact that the two groups were similar in terms of age and body mass index. These results identify additional abnormalities in lipoprotein metabolism that may contribute to the increased risk of coronary heart disease seen in insulin-resistant, nondiabetic subjects (syndrome X).

Sign in / Sign up

Export Citation Format

Share Document