Phases of Drug Metabolism

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What is the primary function of Phase I metabolism in drug metabolism?

To decrease renal elimination of drugs

To attach substituent groups to the drug

To introduce groups that can undergo Phase II reactions (correct)

To increase lipid solubility of drugs

What is the most common Phase I reaction catalyzed by CYP450 enzymes?

Reduction

Oxidation (correct)

Glucuronidation

Hydrolysis

Which of the following enzymes is NOT a Phase I metabolic enzyme?

UDP-glucuronosyltransferase (UGT's) (correct)

Azo reductase

CYP450

Aldehyde dehydrogenase

What is the purpose of the catalytic cycle of CYP450 enzymes?

To split molecular oxygen Signup and view all the answers

Which of the following is a consequence of inhibition of the CYP450 system?

Drug levels increase Signup and view all the answers

What is the main difference between Phase I and Phase II metabolism?

Phase I introduces functional groups, while Phase II attaches solubilizing groups Signup and view all the answers

What is the primary function of flavin monooxygenase in Phase I metabolism?

To catalyze oxidation reactions of nitrogen-containing functional groups Signup and view all the answers

Which of the following is an example of a Phase I oxidation reaction?

Oxidation of a primary alcohol Signup and view all the answers

What is the classification of CYP3A4 enzyme?

Family 3, Subfamily A Signup and view all the answers

What is the purpose of sulphonation in Phase II metabolism?

To attach a solubilizing group to the drug Signup and view all the answers

What is the primary purpose of drug metabolism in the body?

To convert non-polar substances into polar substances for excretion Signup and view all the answers

What is the main site of drug metabolism in the body?

Liver Signup and view all the answers

What is the result of Phase I metabolic reactions?

Conversion of a non-polar substance into a polar substance Signup and view all the answers

What is the consequence of converting an active drug into an inactive metabolite?

Termination of drug action Signup and view all the answers

Which of the following is an example of an active drug being converted into an active metabolite?

Phenacetin Signup and view all the answers

What is the role of enzymes in drug metabolism?

To catalyze the chemical conversion of one drug into another Signup and view all the answers

What is the result of coadministering two drugs that are metabolized by the same enzyme?

Reduced metabolism of one or both drugs Signup and view all the answers

What is the effect of CYP450 inducers on drug metabolism?

Increase the metabolism of drugs Signup and view all the answers

Which of the following is an example of a CYP450 inhibitor?

Ketoconazole Signup and view all the answers

What is the consequence of drug-drug interactions involving synergism?

Increased effect of one or both drugs Signup and view all the answers

What is the purpose of identifying the CYP that metabolizes a drug?

To avoid coadministering drugs that are metabolized by the same enzyme Signup and view all the answers

What is the effect of CYP450 inhibitors on the therapeutic concentration of drugs?

Increase the therapeutic concentration of drugs Signup and view all the answers