Pharmacology - Mock Test 56

Question 551

The following is <u>not</u> true of the cytochrome P450 isoenzyme CYP2D6

A) It generates the hepatotoxic metabolite N-acetyl benzoquinone immine from paracetamol B) It is involved in demethylation of codeine into morphine C) Its altered form is responsible for poor capacity to hydroxylate many drugs including metoprolol D) It is inhibited by quinidine

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Question 552

Which of the following cytochrome P450 isoenzymes is involved in the metabolism of largest number of drugs in human beings and has been implicated in some dangerous drug interactions

A) CYP 3A4 B) CYP 2C9 C) CYP 2E1 D) CYP 1A2

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Question 553

A prodrug is

A) The prototype member of a class of drugs B) The oldest member of a class of drugs C) An inactive drug that is transformed in the body to an active metabolite D) A drug that is stored in body tissues and is then gradually released in the circulation

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Question 554

Which of the following is a prodrug

A) Hydralazine B) Clonidine C) Captopril D) Enalapril

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Question 555

Biotransformation of drugs is primarily directed to

A) Activate the drug B) Inactivate the drug C) Convert lipid soluble drugs into nonlipid soluble metabolites D) Convert nonlipid soluble drugs into lipid soluble metabolites

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Question 556

The plasma protein bound fraction of a drug

A) Contributes to the response at the given moment B) Remains constant irrespective of the total drug concentration C) Remains constant irrespective of the disease state D) Is not available for metabolism unless actively extracted by the liver

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Question 557

High plasma protein binding

A) Increases volume of distribution of the drug B) Facilitates glomerular filtration of the drug C) Minimises drug interactions D) Generally makes the drug long acting

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Question 558

Weakly acidic drugs

A) Are bound primarily to α1 acid glycoprotein in plasma B) Are excreted faster in alkaline urine C) Are highly ionized in the gastric juice D) Do not cross blood-brain barrier

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Question 559

Which of the following is <u>not</u> true of the blood-brain barrier

A) It is constituted by tight junctions between the endothelial cells of brain capillaries and the glial tissue B) It allows passage of lipid soluble drugs into the brain C) It limits entry of highly ionized drugs into the brain D) It regulates passage of substances from brain into blood

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Question 560

The blood-brain barrier, which restricts entry of many drugs into brain, is constituted by

A) P-glycoprotein efflux carriers in brain capillary cells B) Tight junctions between endothelial cells of brain capillaries C) Enzymes present in brain capillary walls D) All of the above

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