ArticleBritish journal of clinical pharmacology2006
Poor correlation between 6beta-hydroxycortisol:cortisol molar ratios and midazolam clearance as measure of hepatic CYP3A activity.
Article in British journal of clinical pharmacology, 2006. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers.
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Who cites it
17 citing papers in PubMed, 47 citations in OpenAlex.
- Identification of the caffeine to trimethyluric acid ratio as a dietary biomarker to characterise variability in cytochrome P450 3A activity.European journal of clinical pharmacology · 2019Trial
- Comparison of two endogenous biomarkers of CYP3A4 activity in a drug-drug interaction study between midostaurin and rifampicin.European journal of clinical pharmacology · 2014Trial
- Evaluation of CYP3A activity in humans using three different parameters based on endogenous cortisol metabolism.Acta pharmacologica Sinica · 2009Trial
- Untargeted Metabolomics Reveal New Endogenous Plasma Biomarkers Associated with CYP3A Inhibition in Humans.Clinical pharmacology and therapeutics · 2026Article
- Deconvoluting Gut Versus Liver Cytochrome P450 3A4 Function: Drug Probes, Biomarkers, and Tissue Biopsy.Journal of clinical pharmacology · 2026Review
- Novel Approaches to Characterize Individual Drug Metabolism and Advance Precision Medicine.Drug metabolism and disposition: the biological fate of chemicals · 2023Review
- The Role of CYP3A in Health and Disease.Biomedicines · 2022Review
- The Effect of Modafinil on the Safety and Pharmacokinetics of Lorlatinib: A Phase I Study in Healthy Participants.Clinical pharmacokinetics · 2021Article
- A Physiology-Based Pharmacokinetic Framework to Support Drug Development and Dose Precision During Therapeutic Hypothermia in Neonates.Frontiers in pharmacology · 2020Review
- Phenotyping of Human CYP450 Enzymes by Endobiotics: Current Knowledge and Methodological Approaches.Clinical pharmacokinetics · 2019Review
- Distribution of Exogenous and Endogenous CYP3A Markers and Related Factors in Healthy Males and Females.The AAPS journal · 2017Article
- Interindividual Variability in Cytochrome P450-Mediated Drug Metabolism.Drug metabolism and disposition: the biological fate of chemicals · 2016Review
- Alteration in cytochrome P450 3A4 activity as measured by a urine cortisol assay in HIV-1-infected pregnant women and relationship to antiretroviral pharmacokinetics.HIV medicine · 2015Article
- Pharmacogenomics of Cytochrome P450 3A4: Recent Progress Toward the "Missing Heritability" Problem.Frontiers in genetics · 2013Article
- Genital tract, cord blood, and amniotic fluid exposures of seven antiretroviral drugs during and after pregnancy in human immunodeficiency virus type 1-infected women.Antimicrobial agents and chemotherapy · 2009Article
- Poor correlation between 6beta-hydroxycortisol:cortisol molar ratios and midazolam clearance as measure of hepatic CYP3A activity: a comment.British journal of clinical pharmacology · 2007Article
- Exome-wide association study of bleeding events in patients receiving direct oral anticoagulants.Science progressObservational
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7 authors at 2 institutions in 1 country.
Funding
Abstract
aimsA non-invasive proposed method for measuring CYP3A activity is the urinary 6beta-hydroxycortisol:cortisol ratio. This ratio has been used as an indicator of CYP3A induction and inhibition, with mixed results. This investigation evaluated the relationship between a validated, biomarker, intravenous midazolam clearance and the urinary cortisol ratio under constitutive conditions and with the influence of a moderate CYP3A inhibitor.
methodsThis was a sequential, cross-over study design. Intravenous midazolam 0.025 mg kg(-1) was administered to 10 male and 10 female subjects once every 14 days for 4 months. Fluvoxamine 150 mg day(-1) was given to all subjects during the last two visits. Total body clearance of midazolam and urinary 6beta-hydroxycortisol:cortisol molar ratio were used as biomarkers of hepatic CYP3A activity.
resultsNo significant correlations were found between these two markers (r(2) < 0.5, P > 0.05). Larger interindividual and intra-individual variability in CYP3A activity was observed in 6beta-hydroxycortisol:cortisol ratios compared with midazolam clearances. With fluvoxamine therapy, midazolam clearance values decreased approximately 1.5-fold and cortisol ratios decreased approximately 1.9-fold.
conclusionsThe high intra-individual variability of the urinary cortisol ratio, compared with midazolam, makes this a suboptimal CYP3A phenotyping tool.
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