10 USMLE Pharmacology Quick Review Questions with Answers (Set 4)

These 10 quick USMLE review questions test the high-yield facts that show up again and again on the exam: pharmacokinetics, tardive dyskinesia, CYP450 reactions, filgrastim, benzodiazepines, pralidoxime, atropine, local anesthetics and ondansetron. Each question includes the correct answer.

Written by Dr. Ray Makar, MD, author of the Repeated USMLE Questions eBook series.

Prefer video? Watch daily USMLE case questions on MedFocus by Dr. Ray on YouTube.

How to use this page: read the question, pick your answer, then tap Show Answer and Explanation.

Questions

Question 1. Pharmacokinetics of a drug is defined as which one of the following?

A- Amount of drug needed to produce an effect
B- Effect of a drug on certain body systems
C- Reaction of the body to a drug
D- The movement of a drug within the body

D- The movement of a drug within the body
The correct answer is D

 

Question 2. Which one of the following drugs is associated the most to tardive dyskinesia after use for years?

A- Aripiprazole
B- Chlorpromazine
C- Olanzapine
D- Risperidone

B- Chlorpromazine
The correct answer is B

 

Question 3. Which of the following is the main reaction of hepatic cytochrome P-450 in metabolism?

A- Binding with glucuronic acid
B- Binding with glutathione
C- Hydroxylation
D- Methylation

C- Hydroxylation
The correct answer is C

 

Question 4. Stimulation of hepatic microsomal cytochrome P450 enzymes can cause which one of the following?

A- Decreased metabolism of certain drugs
B- Enhancement of excretion of some drugs
C- Increased intestinal absorption of certain drugs
D- Increased metabolism of certain drugs

D- Increased metabolism of certain drugs- Induction of hepatic cytochrome P450 enzymes leads to increased drug metabolism, which can reduce the effectiveness of drugs that are metabolized by these pathways. It does not decrease metabolism, increase intestinal absorption, or directly enhance excretion.
The correct answer is D

 

Question 5. Which of the following drugs is used after chemotherapy to increase the leukocyte count if it drops?

A- Dexamethasone
B- Filgrastim
C- Interleukin-2
D- Prednisone

B- Filgrastim- Filgrastim (G-CSF) stimulates the bone marrow to increase neutrophil production and is commonly used after chemotherapy to treat or prevent neutropenia. Dexamethasone and prednisone are corticosteroids, and IL-2 is used to stimulate T-cell proliferation, not leukocyte recovery after chemotherapy.
The correct answer is B

 

Question 6. Which of the following drugs has the shortest half-life and is used in acute anxiety?

A- Alprazolam
B- Chlordiazepoxide
C- Clonazepam
D- Flurazepam

A- Alprazolam- Alprazolam has a short half-life and rapid onset of action, making it suitable for acute anxiety episodes. Chlordiazepoxide, clonazepam, and flurazepam all have longer half-lives and are not ideal for quick, short-term relief.
The correct answer is A

 

Question 7. Which one of these drugs reverses both muscarinic and nicotinic effects of organophosphorus compounds by restoring cholinesterase?

A- Atracurium
B- Atropine
C- Physostigmine
D- Pralidoxime

D- Pralidoxime- Pralidoxime reactivates acetylcholinesterase, reversing both muscarinic and nicotinic effects of organophosphate poisoning. Atropine blocks muscarinic symptoms only, and physostigmine actually increases acetylcholine. Atracurium is a neuromuscular blocker and has no role here.
The correct answer is D

 

Question 8. Stimulation of muscarinic receptors by pilocarpine is competitively inhibited by which of the following medications?

A- Atropine
B- Edrophonium
C- Physostigmine
D- Pralidoxime

A- Atropine- Atropine is a competitive antagonist of muscarinic receptors and therefore blocks the muscarinic effects of pilocarpine. Edrophonium and physostigmine increase acetylcholine, and pralidoxime reactivates acetylcholinesterase but does not block muscarinic receptors directly
The correct answer is A

 

Question 9. Which one of the following local anesthetics can NOT be given parenterally because of its physicochemical properties?

A- Benzocaine
B- Etidocaine
C- Mepivacaine
D- Procaine

A- Benzocaine- Benzocaine is used only as a topical anesthetic because it is poorly water-soluble and cannot be reliably or safely administered parenterally. Etidocaine, mepivacaine, and procaine are all injectable local anesthetics.
The correct answer is A

 

Question 10. Which one of the following drugs is the most effective for severe nausea and vomiting of pregnancy?

A- Cimetidine
B- Loratadine
C- Meclizine
D- Ondansetron

D- Ondansetron- Ondansetron is one of the most effective and commonly used medications for nausea and vomiting of pregnancy, especially when symptoms are moderate to severe. Meclizine can help mild cases, but ondansetron provides stronger symptom control. Cimetidine and loratadine are not used for pregnancy-related nausea.
The correct answer is D

 

High-yield points from this set

  • Pharmacokinetics = what the body does to the drug; pharmacodynamics = what the drug does to the body.
  • Typical antipsychotics such as chlorpromazine cause tardive dyskinesia.
  • Filgrastim (G-CSF) raises neutrophils after chemotherapy.
  • Pralidoxime regenerates acetylcholinesterase if given before aging.

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