Medical Pharmacology: Drug Metabolism Practice Questions
Choose the correct answer for each question.
Phase I reactions:
These reactions include hydrolysis, reduction and oxidation.
Phase I enzymes catalyze drug modification by adding:-OH,-COOH,-SH,-O-or NH2. These modifications have little effect on water solubility of the drug.
Both
Neither
Concerning phase I reactions:
Activity of phase I enzymes most typically results in drug inactivation.
Phase I enzymic catalysis of ester hydrolysis of certain drugs leads to drug activation.
Both
Neither
The term "prodrug" refers to a drug that is initially inactive but as a result of metabolic transformation becomes active.
True
False
Prodrugs are activated by either cytochrome P450 enzyme isoforms or flavin-containing monooxygenases.
True
False
Cyclophosphamide, anticancer drug, is a prodrug, requiring activation by cytochrome P450 enzyme isoforms.
True
False
Phase II enzymes catalyze conjugation reactions that result in metabolites with increased water solubility which promotes drug elimination.
True
False
Phase II reactions:
These reactions enhance drug elimination.
These reactions reduce some toxic metabolites caused by oxidative reactions.
Both
Neither
Location of drug biotransformation:
Following oral administration, some drugs are absorbed from the small intestine and pass directly to the liver, undergoing substantial hepatic metabolism (first-pass effect).
Some orally administered drugs such as clonazepam or chlorpromazine are substantially metabolized in the intestine.
Intestinal metabolism may be important in first-pass effects and may be especially
noteworthy in patients with reduced hepatic function.
A & B
B & C
A & C
A, B & C
Drug metabolizing enzyme systems
may be found in lipophilic endoplasmic reticulum membranes associated with
liver and other tissues .
True
False
Associated with smooth endoplasmic reticulum:
Drug metabolism
Protein synthesis
Enzyme class mainly associated with smooth endoplasmic reticulum: mixed function oxidases a.k.a. monooxygenases.
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Source Material:
Buxton ILO Chapter
2: Pharmcokinetics: The Dynamics of Drug Absorption,
Distribution, Metabolism, and Elimiation in Goodman & Gilman's:
The Pharmacological Basis of Therapeutics, 14e, (Brunton LL H
Knollmann BC, eds) McGraw-Hill Education, 2023.
Gonzalez FJ
Coughtrie M Chapter 5: Drug Metabolism in Goodman & Gilman's:
The Pharmacological Basis of Therapeutics, 14e, (Brunton LL H
Knollmann BC, eds) McGraw-Hill Education, 2023.
Holford NHG Chapter
3: Pharmacokinetics & Pharmacodynamics: Rational Dosing &
the Time Course of Drug Action: in Basic & Clinical
Pharmacology (Katzung BG, Editor; Vanderah TW, Associate
editor) 15e McGraw Hill 2021.
Correia MA Chapter 4
Drug Biotransformation in Basic &
Clinical Pharmacology (Katzung BG, Editor; Vanderah TW, Associate
editor) 15e McGraw Hill 2021.
Baca QJ Golan DE
Pharmacokinetics Chapter 3: Principles of Pharmacology:
The Pathophysiologic Basis of Drug Therapy. (Golan DE, editor-in
chief, Armstrong EJ Armstrong AW, associate editors) 4e Wolters
Kluwer 2017.
Guengerich FP
Chapter 4: Drug Metabolism in
Principles of Pharmacology: The Pathophysiologic Basis of Drug Therapy. (Golan DE, editor-in
chief, Armstrong EJ Armstrong AW, associate editors) 4e Wolters
Kluwer 2017.
Flood P Shafer SL
Chapter 2 Basic Principles of Pharmacology in Stoelting's
Pharmacology & Physiology in Anesthetic Practice (Glood P
Rathmell JP Urman RD, eds) 6e Wolters Kluwer 2022.
Burchum JR Rosenthal
LD Lehne's Pharmacology for Nursing Care Unit II Chapter 4
Pharmcokinetics 11 e Elsevier 2022.
