Related Experiment Video
Updated: Jul 31, 2026
10:44
Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
Published on: March 28, 2017
Cytochrome P450: new nomenclature and clinical implications
American Family Physician
|February 3, 1998
Summary
Understanding cytochrome P450 (CYP450) enzyme functions helps predict drug interactions. This knowledge aids physicians in managing patient responses and preventing adverse events like cardiac dysrhythmias.
Area of Science:
- Pharmacology
- Biochemistry
- Drug Metabolism
Background:
- Cytochrome P450 (CYP450) enzymes are crucial for drug metabolism.
- Inhibition or induction of CYP450 enzymes is a primary cause of drug interactions.
- Specific CYP450 subfamilies (e.g., CYP3A, CYP1A2, CYP2D6) are implicated in various drug interactions.
Observation:
- The CYP3A subfamily mediates interactions with nonsedating antihistamines and cisapride, potentially causing cardiac dysrhythmias.
- CYP3A4 and CYP1A2 are involved in theophylline drug interactions.
- CYP2D6 metabolizes numerous psychotherapeutic agents.
- Protease inhibitors for HIV treatment are metabolized by CYP450 enzymes, leading to numerous drug interactions.
Findings:
- Drug interactions are frequently mediated by the modulation of cytochrome P450 (CYP450) enzyme activity.
- Key CYP450 enzymes like CYP3A4, CYP1A2, and CYP2D6 play distinct roles in metabolizing diverse drug classes.
- The metabolism of HIV protease inhibitors by CYP450 enzymes highlights their potential for significant drug-drug interactions.
Implications:
- Understanding CYP450 enzyme characteristics is vital for predicting and managing drug interactions.
- Physicians can better anticipate patient responses to medications by considering CYP450 involvement.
- This knowledge supports safer and more effective therapeutic regimens, particularly for patients on multiple medications or with conditions like HIV.
More Related Videos
07:38A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s
Published on: September 25, 2017
09:33Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling
Published on: March 20, 2018
Related Concept Videos
01:17Drug Nomenclature
During the development of a new pharmaceutical, the manufacturer initially assigns a code name to the drug. Once approved, the drug receives a United States Adopted Name (USAN)—a generic, nonproprietary designation. Upon being listed in the United States Pharmacopeia, this nonproprietary name becomes the drug's official name. Additionally, the manufacturer assigns a proprietary name or trademark, which serves as the brand name under which the drug is marketed. It is worth noting that the same...
01:19Phase II Reactions: Miscellaneous Conjugation Reactions
Phase II biotransformations are detoxification mechanisms that conjugate xenobiotics with endogenous substances, neutralizing their toxicity.
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
01:16Therapeutic Drug Monitoring: Overview and Classification
Therapeutic Drug Monitoring (TDM) is a clinical practice that measures specific drug levels in a patient's blood at designated intervals to ensure the drug concentration stays within a therapeutic range. This monitoring is crucial for optimizing individual dosage regimens, enhancing therapeutic efficacy, and minimizing drug-related toxicity. TDM is vital for drugs with narrow therapeutic windows, significant variability in pharmacokinetics, and a clear correlation between plasma levels and...
01:27Pharmacogenetics of Drug Metabolism: Overview
Genetic polymorphism in drug metabolism is crucial to the inter-individual variability observed in drug responses. Drug metabolism primarily involves the chemical modification of drugs and other xenobiotics to enhance their elimination by increasing their polarity. Two main classes of enzymes mediate this biotransformation process: Phase I enzymes, primarily cytochrome P450s, catalyze oxidation and reduction reactions, while other enzymes, such as esterases, mediate hydrolysis, and Phase II...
01:28Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Cytochrome P450 (CYP450) enzymes are a superfamily of heme-containing monooxygenases that play a pivotal role in Phase I drug metabolism by catalyzing oxidation and reduction reactions.These enzymes transform lipophilic xenobiotics into more hydrophilic metabolites, facilitating subsequent Phase II conjugation and eventual excretion. The CYP450 family is classified into families (e.g., CYP1–CYP3) and subfamilies (e.g., CYP2A, CYP2C), based on amino acid sequence homology.CYP450 isoenzymes,...
01:27Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Phase II biotransformation reactions are essential for detoxifying and eliminating xenobiotics, including many pharmaceutical compounds. These reactions typically involve conjugation, the covalent attachment of polar endogenous groups such as glucuronic acid, sulfate, methyl, or acetyl moieties to functional groups introduced during Phase I metabolism. The resulting conjugates are more water-soluble, enabling efficient renal or biliary excretion.The major classes of Phase II enzymes include...