11 USMLE Pharmacology Quick Review Questions with Answers (Set 16)

These 11 quick USMLE review questions test high-yield facts that show up again and again on the exam: cyclosporine, beta-blockers in angina, TCAs and antipsychotics, desmopressin, dexrazoxane, benzodiazepines, leuprolide, muscarinic agonists, organophosphates and pioglitazone. 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. Which of the following is the mechanism of action of metoprolol in a case of angina?

A- Reduces the production of epinephrine
B- Reduces the requirement of the heart for oxygen
C- Increases central venous pressure
D- Increases peripheral resistance

B- Reduces requirement of the heart for oxygen- Beta blockers lowers heart rate, blood pressure and contractility without affecting cardiac output and all these lead to reduction of requirement for myocardial oxygen
The correct answer is B

 

Question 2. Which of the following side effects occurs with both tricyclic antidepressants and phenothiazines?

A- Excessive salivation
B- Orthostatic hypotension
C- Seizures
D- Weight loss

B- Orthostatic hypotension- Both types of drugs block alpha-adrenergic receptors which may cause postural hypotension. They also decrease salivation, decrease seizures’ incidents and lead to weight gain.
The correct answer is B

 

Question 3. Which of the following medications is useful to distinguish nephrogenic from neurogenic diabetes insipidus?

A- Acetazolamide
B- Demeclocycline
C- Desmopressin
D- Hydrochlorothiazide

C- Desmopressin- It treats neurogenic DI through selective activation of V2 receptors in the kidney. Nephrogenic DI is treated with thiazides.
The correct answer is C

 

Question 4. Which of the following drugs is most likely protective against the toxicity of doxorubicin?

A- Dexrazoxane
B- Leucovorin
C- Mesna
D- Vitamin C

A-Dexrazoxane- It is iron-chelating agent that prevents the formation of free radicals and reduces the well-known cardiotoxicity.
The correct answer is A

 

Question 5. Which of the following is the mechanism of action of benzodiazepines in the treatment of insomnia?

A- Alpha adrenergic antagonist
B- Binds to serotonin receptors
C- Binds to GABA receptors
D- Dopamine receptor agonist

C- Binds to GABA receptors- Benzodiazepines are known for their activation of GABA receptors. Other choices are distractions.
The correct answer is C

 

Question 6. A single injection of leuprolide was given to a man 2 weeks ago. Which of the following changes could be revealed today?

A- Decreased testosterone production
B- Increased FSH receptors
C- Increased LH receptors
D- Increased testosterone production

D- Increased testosterone production- No effect on receptors but it increases FSH/LH and steroid production.
The correct answer is D

 

Question 7. Which one of the following actions is produced by muscarinic cholinergic agonists?

A- Activation of inhibitory G protein
B- Decreased IP3 production
C- Decreased release of intracellular calcium
D- Inhibition of phospholipase C

A- Activation of inhibitory G protein- Muscarinic cholinergic agonists activate inhibitory G protein, activate phospholipase C, and increase IP3 production and release of intracellular calcium.
The correct answer is A

 

Question 8. Organophosphorus poisoning can be treated with which of the following agents?

A- Atenolol
B- Atropine
C- Ipratropium bromide
D- Physostigmine

B- Atropine- It blocks the action of acetyl choline peripherally and though CNS. Atenolol has no role in this case. Ipratropium bromide doesn’t penetrate BBB and physostigmine would worsen the case.
The correct answer is B

 

Question 9. Which of the following is the mechanism of action of pioglitazone in diabetic patients?

A- Decreases insulin breakdown
B- Increases glucose excretion
C- Increases glucose uptake in muscle cells
D- Increases insulin release

C- Increases glucose uptake in muscle cells- This medication does not affect insulin release or degradation but it increases glucose uptake by adipose and muscle tissues.
The correct answer is C

 

Question 10. Which of the following is the effect of digoxin on a case of heart failure?

A- Decreased stroke volume and vagal activity
B- Increased stroke volume and cardiac output
C- Increased sympathetic tone and decreased vagal activity
D- Rapid conduction through AV node

B- Increased stroke volume and cardiac output- Digoxin effect on a failing heart includes also decreased sympathetic tone and increased vagal activity resulting in delayed conduction through AV node and inhibition of SA node.
The correct answer is B

 

Question 11. Which of the following is the mechanism of action of flumazenil in the treatment of lorazepam toxicity?

A- Competitive inhibition at benzodiazepine receptors
B- Inhibition of alpha adrenoceptors
C- Noncompetitive inhibition of benzodiazepine receptors
D- Stimulation of dopamine receptors

A- Competitive inhibition at benzodiazepine receptors- Flumazenil reverses the action of benzodiazepines on GABA receptors.
The correct answer is A

 

High-yield points from this set

  • Desmopressin separates central from nephrogenic diabetes insipidus.
  • Dexrazoxane protects against doxorubicin cardiotoxicity.
  • Continuous GnRH agonists (leuprolide) first raise, then suppress, testosterone.
  • Pioglitazone increases insulin sensitivity (PPAR-gamma).

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