18 Questions
Which enzyme is responsible for the O-methylation of important neurotransmitters such as norepinephrine and dopamine?
Catechol-O-methyltransferase (COMT)
Which of the following is the activated coenzyme involved in methylation reactions?
S-adenosylmethionine (SAM)
Which type of methylation reaction does not create a quaternary ammonium derivative and thus tends to result in pharmacologically inactive compounds?
O-methylation
Which of the following methyltransferases is NOT typically involved in the metabolism of xenobiotics?
Histamine-specific N-methyltransferase
Which of the following is NOT an example of a phase II reaction involving a conjugation process?
Acetylation
Which of the following factors affects the metabolism of drugs and xenobiotics the most?
The metabolism of several different phase I and phase II pathways
Which metabolic pathway is primarily responsible for terminating the biological activity of biogenic amines?
Methylation
Which of the following drugs exhibits acetylation polymorphism resulting in variable therapeutic and toxicological responses?
Isoniazid
Which of the following populations is typically categorized as slow acetylators?
Egyptians
Which phase II reaction is least likely to be involved in the metabolism of drugs and xenobiotics?
Methylation
Which of the following biogenic amines is not primarily metabolized via methylation?
Dopamine
Which of the following statements about acetylation polymorphism is true?
Slow acetylators are more likely to show an inadequate therapeutic response to standard drug doses
What is the primary determinant of the relative amount of a particular metabolite?
The concentration and activity of the enzyme(s) responsible for biotransformation
What is the consequence of a decreased rate of metabolism of a drug?
Increased intensity and duration of the drug action
What is a factor that can affect drug metabolism and is influenced by the drug's chemical structure?
Chemical factor
What type of stereoselectivity refers to the preferential interaction of one stereoisomer with metabolizing enzymes at a specific region of the molecule?
Regioselectivity
What is the consequence of an increased rate of metabolism of a drug?
Decreased intensity and duration of the drug action
What is an example of a biological factor that can affect drug metabolism?
Nutritional status
Test your knowledge on drug metabolism, pharmacological action, and the impact of metabolic rates on drug intensity and toxicity. Understand the relationship between enzyme concentration, drug metabolism, and toxicity levels.
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