Pharmacology for the USMLE: Exam Questions and Preparation
How Pharmacology is tested on the USMLE, the high-yield topics, a preparation approach and original practice questions with explained answers.
Pharmacology on the USMLE asks about the mechanism, the key adverse effect, the interaction or the antidote. The subject rewards organized lists and an understanding of principles, such as why a drug accumulates and which enzymes metabolize it.
Step 1 is reported as pass/fail, and its questions are integrated across disciplines and organ systems, so the subject labels below are study aids, not separate exams. The practice questions here are original and written to show the style of reasoning the exam rewards; they are not real exam items. Confirm the current content outline on the official USMLE website.
How Pharmacology is tested
Questions give a clinical scenario and ask which drug is used, how it works, what harm it can cause or how to reverse it. Pharmacokinetic questions ask you to calculate or reason about doses, half-life and clearance.
High-yield topics
- Pharmacokinetics: volume of distribution, clearance, half-life, loading and maintenance doses
- Pharmacodynamics: potency, efficacy, agonists and antagonists
- Autonomic drugs and their receptors
- Cardiovascular, renal and endocrine drugs
- Antimicrobials, antivirals and antifungals
- CNS drugs, anesthetics and analgesics
- Toxicology, antidotes and cytochrome P450 interactions
Preparation approach
- Study drugs by class, learning the prototype and the shared mechanism and adverse effects.
- Memorize the high-yield antidotes and the CYP450 inducers and inhibitors.
- Practice the pharmacokinetic equations until they are automatic.
- After each question block, write the adverse effect and the reason for every wrong option you chose.
Practice questions
Question 1
A patient presents several hours after intentionally ingesting a large amount of acetaminophen. Which treatment works by replenishing hepatic glutathione?
- A. Flumazenil
- B. N-acetylcysteine
- C. Naloxone
- D. Fomepizole
- E. Physostigmine
Answer: B. N-acetylcysteine restores glutathione, which detoxifies the toxic metabolite NAPQI. It is most effective when started early.
Question 2
A man stabilized on warfarin starts rifampin for tuberculosis, and his INR falls below target. What is the most likely mechanism?
- A. Inhibition of vitamin K epoxide reductase
- B. Induction of cytochrome P450 enzymes
- C. Displacement of warfarin from albumin
- D. Decreased intestinal absorption of warfarin
- E. Competitive antagonism at the receptor
Answer: B. Rifampin induces cytochrome P450 enzymes, increasing warfarin metabolism and lowering its effect, so the INR falls.
Question 3
A drug has a volume of distribution of 100 L and complete bioavailability. The target plasma concentration is 2 mg/L. What loading dose is needed?
- A. 2 mg
- B. 20 mg
- C. 50 mg
- D. 200 mg
- E. 2,000 mg
Answer: D. The loading dose equals the volume of distribution times the target concentration: 100 L x 2 mg/L = 200 mg.
Make it a plan
Put these subjects inside a dedicated study block with timed question blocks and careful review. See our Step 1 preparation timeline for a schedule and weekly milestones. This article is general educational guidance and not an individualized study plan.
Educational content only. Confirm current exam requirements with USMLE.