Pharmacology Quiz

Questions and Answers

Which CYP enzyme is involved in the metabolism of clopidogrel and proton pump inhibitors?

CYP 2C19 (correct)

CYP 3A4

CYP 2A

CYP 2B

Which of the following statements is true about protein binding of drugs?

Drugs having higher affinity for a plasma protein can displace another drug from the same protein (correct)

Acidic drugs bind to alpha-1 acid glycoprotein in plasma

Basic drugs bind to albumin in plasma

Sex steroid hormones do not bind to any protein in plasma

What is the pH at which a drug is 50% ionized?

pH of the plasma

pKa of the drug (correct)

pH of the solution

pH of the gut

What is the primary factor that determines the extent of ionization of a drug?

pKa of the drug Signup and view all the answers

What happens to the degree of ionization of a weak acidic drug when the pH is near its pKa?

It is greatly affected by small changes Signup and view all the answers

What is the ionization state of phenobarbitone at an acid pH?

Largely unionized Signup and view all the answers

Which of the following statements about bioavailability is false?

Bioavailability is always 100% Signup and view all the answers

What is the significance of knowing the pKa of a drug?

It is useful in predicting the drug's behavior in various body fluids Signup and view all the answers

What is the volume of plasma completely cleared of a specimen compound per unit time and measured as a test of kidney function?

Clearance Signup and view all the answers

What is the formula to calculate the volume of distribution of a drug?

Vd = Dose administered IV / Plasma concentration Signup and view all the answers

What is the conjugation reaction involved in the metabolism of sulphonamides?

Acetylation Signup and view all the answers

Which anesthetic is associated with the redistribution phenomenon?

Thiopentone Signup and view all the answers

Which of the following is a nonsynthetic phase I reaction for drug detoxification?

Oxidation Signup and view all the answers

What is the primary role of the kidney in pharmacokinetics?

To excrete drugs Signup and view all the answers

What is bioavailability?

The percentage of drug detected in the systemic circulation after its administration Signup and view all the answers

What is the primary role of conjugation reactions in drug metabolism?

To increase the polarity of drugs Signup and view all the answers

What is an example of physiological antagonism?

Insulin-Glucagon Signup and view all the answers

Which of the following drugs does not act on ionic channels?

Insulin Signup and view all the answers

What does efficacy of a drug refer to?

Maximum response a drug can produce Signup and view all the answers

Which of the following drugs is known to cause an SLE-like reaction?

Hydralazine Signup and view all the answers

What is the term for a drug that binds to a receptor and causes an action opposite to that of an agonist?

Inverse Agonist Signup and view all the answers

What is the study of how variation in the human genome affects the response to medications known as?

Pharmacogenomics Signup and view all the answers

What is the term for a drug that has a high affinity for a receptor but does not activate it?

Neutral Antagonist Signup and view all the answers

Which of the following is an example of a partial agonist?

Isoproterenol Signup and view all the answers

What type of dose-response curve provides information on variation in sensitivity of response to increasing doses of the drug in different individuals?

Graded DRC Signup and view all the answers

What is the primary goal of Phase 1 in drug development?

To determine efficacy and dose in patients Signup and view all the answers

What is the effect on Vmax and Km in competitive inhibition?

Km increases, Vmax remains unchanged Signup and view all the answers

Which of the following drugs is contraindicated in acute intermittent porphyria?

Barbiturates Signup and view all the answers

What is drug efficacy defined as?

The maximal effect that a drug can produce Signup and view all the answers

What is the purpose of Phase 2 in drug development?

To conduct randomized controlled trials in patients Signup and view all the answers

What is the effect on Vmax and Km in non-competitive inhibition?

Vmax decreases, Km remains same Signup and view all the answers

What is the goal of Phase 3 in drug development?

To conduct randomized controlled trials in patients Signup and view all the answers

What is the most common cytochrome P450 enzyme involved in drug metabolism?

CYP3A4 Signup and view all the answers

Which of the following drugs is known to bind to albumin?

Propranolol Signup and view all the answers

Which of the following is an enzyme inhibitor?

Ketoconazole Signup and view all the answers

Which of the following antiepileptics is NOT a microsomal enzyme inducer?

Valproate Signup and view all the answers

What is the effect of grapefruit juice on drug metabolism?

Enzyme inhibitor Signup and view all the answers

Which of the following can result in oral contraceptive failure?

Concurrent use of rifampicin Signup and view all the answers

Which of the following is a substrate for CYP3A4?

All of the above Signup and view all the answers

Which of the following statements about drug metabolism is TRUE?

All of the above. Signup and view all the answers

Study Notes

Enzymes and Metabolism

CYP 2C19 is the mitochondrial enzyme involved in the metabolism of clopidogrel and proton pump inhibitors.
A drug's extent of ionization depends on its pKa and the pH of the solution it is dissolved in.

Drug-Protein Binding

Acidic drugs bind to albumin in plasma.
Basic drugs bind to alpha-1 acid glycoprotein in plasma.
Drugs with higher affinity for a plasma protein can displace other drugs from the same protein.

Bioavailability

Bioavailability is the percentage of a drug detected in the systemic circulation after its administration.
Volume of plasma completely cleared of a specific compound per unit time is a measure of kidney function.

Volume of Distribution

Volume of distribution (Vd) is the ratio of the dose administered IV to the plasma concentration.

Redistribution Phenomenon

Redistribution phenomenon is seen in Thiopentone.

Conjugation Reactions

Sulphonamide is conjugated with Acetylation.
Oxidation is a nonsynthetic phase I reaction for drug detoxification.

Cytochrome P450 Enzymes

CYP3A4 is the cytochrome P450 enzyme most commonly involved in drug metabolism.
Ketoconazole is an enzyme inhibitor.
Rifampicin is an enzyme inducer.

Drug Metabolism

Grapefruit juice is an enzyme inhibitor.
Phenobarbitone and Phenytoin are microsomal enzyme inducers.
Valproate is not an enzyme inducer.

Pharmacodynamics

Efficacy of a drug refers to the maximum response it can produce.
Inverse agonist is a drug that binds to a receptor and causes an action opposite to that of an agonist.

Pharmacogenomics

Pharmacogenomics is the study of how variations in the human genome affect the response to medications.

Dose-Response Curve

A graded DRC shows the variation in sensitivity of response to increasing doses of a drug in different individuals.
In competitive inhibition, Km increases, and Vmax remains unchanged.
In non-competitive inhibition, Vmax decreases, and Km remains unchanged.

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Description

Test your knowledge of pharmacology with these multiple-choice questions. Identify the correct mitochondrial enzyme involved in clopidogrel metabolism and identify the wrong statement about drug binding.