CYP Enzymes and Drug Metabolism Quiz

Variability of drug metabolism, particularly involving cytochrome P450 (CYP) enzymes, is considered an important complicating factor in which of the following fields?

• Pharmacology and Toxicology

• Agronomy and Botany

• Meteorology and Climatology

• Geophysics and Seismology

How many CYP genes are found in the human genome?

• 15

• 25

• 57

• 7,000

Which of the following CYP families primarily metabolise xenobiotics, including the majority of small molecule drugs currently in use?

• Families 1, 2, and 3

• Families 4, 5, and 6

• Families 7, 8, and 9

• Families 10, 11, and 12

Which CYP isoform is the most abundant in the human liver, comprising approximately 25% of the total CYP, and plays a very important role in human metabolism?

• CYP1A2

• CYP2D6

• CYP3A4

• CYP2C9

What percentage of individuals in Caucasian populations typically exhibit the poor metaboliser (PM) phenotype for CYP2D6?

• 1 to 2%

• 5 to 10%

• 18 to 22%

• 29%

Which of the following is NOT a main category of cytochrome P450 (CYP) inhibition mechanisms?

• Reversible inhibition

• Quasi-irreversible inhibition

• Irreversible inhibition

• Allosteric activation

Which of the following is considered a preferred in vivo probe substrate for CYP1A2 enzyme activity studies?

• Tolbutamide

• Coumarin

• Midazolam

• Caffeine

Which antiarrhythmic drug is traditionally utilised as a highly selective and very efficient CYP2D6 inhibitor, despite not being a substrate of CYP2D6 itself?

• Amiodarone

• Fluconazole

• Quinidine

• Paroxetine

The induction of CYP2E1 by xenobiotics like ethanol and isoniazid is primarily regulated by which mechanism?

• Increased gene transcription

• Decreased protein synthesis

• Stabilization of mRNA and protein

• Allosteric activation

Which of the following is a well-known inducer of human CYP3A4 activity?

• Ketoconazole

• Grapefruit juice

• Rifampicin

• Fluvoxamine