scholarly journals Cytochrome P450 1A2 is the most important enzyme for hepatic metabolism of the metamizole metabolite 4‐methylaminoantipyrine

2021 ◽  
Author(s):  
Fabio Bachmann ◽  
Henriette E. Meyer zu Schwabedissen ◽  
Urs Duthaler ◽  
Stephan Krähenbühl
Keyword(s):  
Cytochrome P450 ◽  
Hepatic Metabolism ◽  
Cytochrome P450 1A2 ◽  
Important Enzyme

Decreased metabolism of 13C-caffeine via hepatic CYP1A2 in marasmus and kwashiorkor based on breath test

2015 ◽  
Vol 26 (1) ◽  
Author(s):  
Kazeem Adeola Oshikoya ◽  
Kenneth Smith ◽  
Helen Sammons ◽  
Imti Choonara
Keyword(s):  
Cytochrome P450 ◽  
Breath Test ◽  
Hepatic Metabolism ◽  
Cytochrome P450 1A2 ◽  
Cyp1a2 Activity ◽  
Nutritional Recovery

AbstractHepatic metabolism of drugs has been rarely studied in children with malnutrition. Caffeine breath test (CBT) has been used to determine the activity of cytochrome P450 1A2 (CYP1A2) enzymes in children. We used the CBT to assess how marasmus and kwashiorkor differentially affectA total of 45 children composed of 15 children per group of malnutrition (marasmus, marasmic-kwashiorkor, and kwashiorkor) were studied during malnutrition and after nutritional recovery. After an overnight fast, patients ingested 3 mg/kgThe CPDR in the expiredHepatic metabolism of caffeine significantly decreased in children with marasmus, marasmic-kwashiorkor, and kwashiorkor compared to after they had recovered nutritionally. This suggests a decreased CYP1A2 activity in all categories of malnutrition.

scholarly journals Cytochrome P450 1A2 is the most important enzyme for hepatic metabolism of the metamizole metabolite 4-methylaminoantipyrine

2021 ◽  
Author(s):  
Fabio Bachmann ◽  
Urs Duthaler ◽  
Henriette Meyerzuschwabidissen ◽  
Stephan Krahenbuhl
Keyword(s):  
Cytochrome P450 ◽  
Healthy Volunteers ◽  
Adverse Reactions ◽  
Hepatic Metabolism ◽  
Double Blind Study ◽  
Double Blind ◽  
Primary Metabolite ◽  
Dose Dependent ◽  
Important Enzyme

Aim: Metamizole (dipyrone) is a prodrug not detectable in serum or urine after oral ingestion. The primary metabolite is 4-methylaminoantipyrine (4-MAA), which can be N-demethylated to 4-aminoantipyrine (4-AA) or oxidized to 4-formylaminoantipyrine (4-FAA) by cytochrome P450 (CYP)-dependent reactions. Our aim was to identify the CYPs involved. Methods: We investigated the metabolism of 4-MAA in vitro using CYP expressing supersomes and the pharmacokinetics of metamizole in the presence of CYP inhibitors in healthy volunteers. Results: The experiments in supersomes revealed CYP1A2 as the major CYP for 4-MAA N-demethylation and 4-FAA formation. CYP2C19 and CYP2D6 contributed to N-demethylation but not to FAA formation. In the subsequent clinical study, we investigated the influence of ciprofloxacin (strong CYP1A2 inhibitor), fluconazole (strong CYP2C19 inhibitor) and the combination ciprofloxacin/fluconazole on the pharmacokinetics of a single dose of metamizole in n=12 healthy volunteers in a randomized, placebo-controlled, double-blind study. Both ciprofloxacin and fluconazole inhibited the metabolism of 4-MAA, confirming the in vitro results. Ciprofloxacin, fluconazole and ciprofloxacin/fluconazole increased the AUC0-12h of 4-MAA by 51%, 17% and 92%, respectively. Ciprofloxacin, fluconazole and ciprofloxacin/fluconazole decreased the AUC0-12h of 4-AA by 27%, 12% and 24%, respectively, and of 4-FAA by 33%, 9% and 51%, respectively. Ciprofloxacin, fluconazole and ciprofloxacin/fluconazole increased the half-life of 4-MAA from 3.22 h (placebo) to 3.91, 3.69 and 6.07 h, respectively. Conclusion: CYP1A2 is the major CYP for the conversion of 4-MAA to 4-AA and 4-FAA. CYP1A2 inhibition increases the 4-MAA exposure by a factor of approximately 1.5, which could be relevant for dose-dependent adverse reactions.

Fatty Liver and Impaired Hepatic Metabolism Alters the Congener-Specific Distribution of Polychlorinated Biphenyls (PCBs) in Mice with a Liver-Specific Deletion of Cytochrome P450 Reductase

2020 ◽  
Author(s):  
Xueshu Li ◽  
Chun-Yun Zhang ◽  
Hans-Joachim Lehmler
Keyword(s):  
Cytochrome P450 ◽  
Polychlorinated Biphenyls ◽  
Fatty Liver ◽  
Partition Coefficients ◽  
Hepatic Metabolism ◽  
Gas Chromatography Mass Spectrometry ◽  
Cytochrome P450 Reductase ◽  
P450 Reductase ◽  
Specific Distribution ◽  
Specific Deletion

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that are linked to adverse health outcomes. PCB tissue levels are determinants of PCB toxicity; however, it is unclear how factors, such as an altered metabolism and/or a fatty liver, affect PCB distribution in vivo. We determined the congener-specific disposition of PCBs in mice with a liver specific deletion of cytochrome P450 reductase (KO), a model of fatty liver with impaired hepatic metabolism, and wildtype (WT) mice. Male and female KO and WT mice were exposed orally to Aroclor 1254, a technical PCB mixture. PCBs were quantified in adipose, blood, brain and liver tissues by gas chromatography-mass spectrometry. PCB profiles and levels in tissues were genotype and sex dependent. PCB levels were higher in the liver from KO compared to WT mice. PCB profiles showed clear differences between tissues from the same exposure group. While experimental tissue : blood partition coefficients in KO and WT mice did not follow the trends predicted using a composition-based model, the agreement between experimental and calculated partition coefficients was still reasonable. Thus, a fatty liver and/or an impaired hepatic metabolism alter the distribution of PCBs in mice and the magnitude of the partitioning of PCBs from blood into tissues can be approximated using composition-based models.<br>

scholarly journals Severe Adverse Drug Reactions to Quetiapine in Two Patients Carrying CYP2D6*4 Variants: A Case Report

2021 ◽  
Vol 22 (12) ◽  
pp. 6480
Author(s):  
Céline K. Stäuble ◽  
Markus L. Lampert ◽  
Thorsten Mikoteit ◽  
Martin Hatzinger ◽  
Kurt E. Hersberger ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Case Report ◽  
Adverse Drug Reactions ◽  
Active Metabolite ◽  
Hepatic Metabolism ◽  
Cytochrome P450 3A4 ◽  
Drug Reactions ◽  
Drug Induced ◽  
Potential Impact ◽  
Intermediate Metabolizer

We report two cases of patients who developed severe adverse drug reactions including persistent movement disorders, nausea, and vertigo during treatment with quetiapine at maximum daily doses ranging between 300 and 400 mg. The extensive hepatic metabolism of quetiapine is mainly attributed to cytochrome P450 3A4 (CYP3A4). However, there is recent evidence supporting the idea of CYP2D6 playing a role in the clearance of the quetiapine active metabolite norquetiapine. Interestingly, both patients we are reporting of are carriers of the CYP2D6*4 variant, predicting an intermediate metabolizer phenotype. Additionally, co-medication with a known CYP2D6 inhibitor and renal impairment might have further affected quetiapine pharmacokinetics. The herein reported cases could spark a discussion on the potential impact of a patient’s pharmacogenetic predisposition in the treatment with quetiapine. However, further studies are warranted to promote the adoption of pharmacogenetic testing for the prevention of drug-induced toxicities associated with quetiapine.

Virtual Screening and Prediction of Site of Metabolism for Cytochrome P450 1A2 Ligands

2009 ◽  
Vol 49 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Poongavanam Vasanthanathan ◽  
Jozef Hritz ◽  
Olivier Taboureau ◽  
Lars Olsen ◽  
Flemming Steen Jørgensen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Virtual Screening ◽  
Cytochrome P450 1A2
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