Biomaterial Database

Update: clinically significant cytochrome P-450 drug interactions. 1998

E L Michalets

Department of Pharmacy, Mission-St. Joseph's Health System, and the University of North Carolina School of Pharmacy Community-Based Practice, Asheville 28801, USA.

Recent technologies have resulted in an explosion of information concerning the cytochrome P-450 isoenzymes and increased awareness of life-threatening interactions with such commonly prescribed drugs as cisapride and some antihistamines. Knowledge of the substrates, inhibitors, and inducers of these enzymes assists in predicting clinically significant drug interactions. In addition to inhibition and induction, microsomal drug metabolism is affected by genetic polymorphisms, age, nutrition, hepatic disease, and endogenous chemicals. Of the more than 30 human isoenzymes identified to date, the major ones responsible for drug metabolism include CYP3A4, CYP2D6, CYP1A2, and the CYP2C subfamily.

UI	MeSH Term	Description	Entries
D010600	Pharmacology	The study of the origin, nature, properties, and actions of drugs and their effects on living organisms.	Pharmacologies
D003577	Cytochrome P-450 Enzyme System	A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.	Cytochrome P-450,Cytochrome P-450 Enzyme,Cytochrome P-450-Dependent Monooxygenase,P-450 Enzyme,P450 Enzyme,CYP450 Family,CYP450 Superfamily,Cytochrome P-450 Enzymes,Cytochrome P-450 Families,Cytochrome P-450 Monooxygenase,Cytochrome P-450 Oxygenase,Cytochrome P-450 Superfamily,Cytochrome P450,Cytochrome P450 Superfamily,Cytochrome p450 Families,P-450 Enzymes,P450 Enzymes,Cytochrome P 450,Cytochrome P 450 Dependent Monooxygenase,Cytochrome P 450 Enzyme,Cytochrome P 450 Enzyme System,Cytochrome P 450 Enzymes,Cytochrome P 450 Families,Cytochrome P 450 Monooxygenase,Cytochrome P 450 Oxygenase,Cytochrome P 450 Superfamily,Enzyme, Cytochrome P-450,Enzyme, P-450,Enzyme, P450,Enzymes, Cytochrome P-450,Enzymes, P-450,Enzymes, P450,Monooxygenase, Cytochrome P-450,Monooxygenase, Cytochrome P-450-Dependent,P 450 Enzyme,P 450 Enzymes,P-450 Enzyme, Cytochrome,P-450 Enzymes, Cytochrome,Superfamily, CYP450,Superfamily, Cytochrome P-450,Superfamily, Cytochrome P450
D004347	Drug Interactions	The action of a drug that may affect the activity, metabolism, or toxicity of another drug.	Drug Interaction,Interaction, Drug,Interactions, Drug
D004364	Pharmaceutical Preparations	Drugs intended for human or veterinary use, presented in their finished dosage form. Included here are materials used in the preparation and/or formulation of the finished dosage form.	Drug,Drugs,Pharmaceutical,Pharmaceutical Preparation,Pharmaceutical Product,Pharmaceutic Preparations,Pharmaceutical Products,Pharmaceuticals,Preparations, Pharmaceutical,Preparation, Pharmaceutical,Preparations, Pharmaceutic,Product, Pharmaceutical,Products, Pharmaceutical
D004790	Enzyme Induction	An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.	Induction, Enzyme
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006899	Mixed Function Oxygenases	Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.	Hydroxylase,Hydroxylases,Mixed Function Oxidase,Mixed Function Oxygenase,Monooxygenase,Monooxygenases,Mixed Function Oxidases,Function Oxidase, Mixed,Function Oxygenase, Mixed,Oxidase, Mixed Function,Oxidases, Mixed Function,Oxygenase, Mixed Function,Oxygenases, Mixed Function
D051544	Cytochrome P-450 CYP3A	A cytochrome P-450 suptype that has specificity for a broad variety of lipophilic compounds, including STEROIDS; FATTY ACIDS; and XENOBIOTICS. This enzyme has clinical significance due to its ability to metabolize a diverse array of clinically important drugs such as CYCLOSPORINE; VERAPAMIL; and MIDAZOLAM. This enzyme also catalyzes the N-demethylation of ERYTHROMYCIN.	CYP3A,CYP3A4,CYP3A5,Cytochrome P-450 CYP3A4,Cytochrome P-450 CYP3A5,Cytochrome P-450IIIA,Cytochrome P450 3A,Cytochrome P450 3A4,Cytochrome P450 3A5,Erythromycin N-Demethylase,Taurochenodeoxycholate 6-alpha-Monooxygenase,3A5, Cytochrome P450,6-alpha-Monooxygenase, Taurochenodeoxycholate,Cytochrome P 450 CYP3A,Cytochrome P 450 CYP3A4,Cytochrome P 450 CYP3A5,Cytochrome P 450IIIA,Erythromycin N Demethylase,N-Demethylase, Erythromycin,P-450 CYP3A, Cytochrome,P-450 CYP3A4, Cytochrome,P-450 CYP3A5, Cytochrome,P-450IIIA, Cytochrome,P450 3A, Cytochrome,P450 3A5, Cytochrome,Taurochenodeoxycholate 6 alpha Monooxygenase
D019388	Cytochrome P-450 CYP1A2	A cytochrome P450 enzyme subtype that has specificity for relatively planar heteroaromatic small molecules, such as CAFFEINE and ACETAMINOPHEN.	CYP1A2,Phenacetin O-Dealkylase,CYP 1A2,Caffeine Demethylase,Cytochrome P-450 LM(4),Cytochrome P-450 LM4,Cytochrome P-450d,Cytochrome P450 1A2,CYP1A2, Cytochrome P-450,Cytochrome P 450 CYP1A2,Cytochrome P 450 LM4,Cytochrome P 450d,Demethylase, Caffeine,O-Dealkylase, Phenacetin,P-450 LM4, Cytochrome,Phenacetin O Dealkylase
D019389	Cytochrome P-450 CYP2D6	A cytochrome P450 enzyme that catalyzes the hydroxylation of many drugs and environmental chemicals, such as DEBRISOQUINE; ADRENERGIC RECEPTOR ANTAGONISTS; and TRICYCLIC ANTIDEPRESSANTS. This enzyme is deficient in up to 10 percent of the Caucasian population.	CYP2D6,Debrisoquine 4-Hydroxylase,Debrisoquine Hydroxylase,CYP 2D6,Cytochrome P450 2D6,Debrisoquine 4-Monooxygenase,Imipramine 2-Hydroxylase,Sparteine Monooxygenase,2-Hydroxylase, Imipramine,4-Hydroxylase, Debrisoquine,4-Monooxygenase, Debrisoquine,CYP2D6, Cytochrome P-450,Cytochrome P 450 CYP2D6,Debrisoquine 4 Hydroxylase,Debrisoquine 4 Monooxygenase,Hydroxylase, Debrisoquine,Imipramine 2 Hydroxylase,Monooxygenase, Sparteine,P-450 CYP2D6, Cytochrome,P450 2D6, Cytochrome