USMLE Step 1 Exam Pharmacology/Integrated
Basic Science Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2025/2026 Q&A | Instant Download
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1. A 62-year-old man with hypertension is started on a drug that
inhibits angiotensin-converting enzyme (ACE). Which of the following
is a common adverse effect of ACE inhibitors?
A) Hyperkalemia
B) Hypokalemia
C) Hypoglycemia
D) Neutropenia
Answer: A) Hyperkalemia
ACE inhibitors reduce aldosterone secretion, which decreases
potassium excretion, leading to hyperkalemia.
2. A patient is prescribed a selective β1-blocker for hypertension.
Which of the following is a potential side effect?
A) Bronchospasm
B) Bradycardia
C) Hypoglycemia
D) Hyperthyroidism
Answer: B) Bradycardia
Selective β1-blockers decrease heart rate and contractility, which can
result in bradycardia.
3. A 25-year-old woman is treated with a drug that inhibits
dihydrofolate reductase. Which drug is most likely prescribed?
,A) Methotrexate
B) Trimethoprim
C) 5-Fluorouracil
D) Leucovorin
Answer: A) Methotrexate
Methotrexate inhibits dihydrofolate reductase, reducing
tetrahydrofolate levels and impairing DNA synthesis.
4. A patient receiving warfarin therapy develops bleeding. Which
vitamin can be administered as an antidote?
A) Vitamin A
B) Vitamin D
C) Vitamin K
D) Vitamin E
Answer: C) Vitamin K
Vitamin K is required for γ-carboxylation of clotting factors II, VII, IX,
and X; supplementation reverses warfarin anticoagulation.
5. A drug is given that irreversibly inhibits cyclooxygenase-1 (COX-1)
in platelets. Which effect is expected?
A) Increased platelet aggregation
B) Decreased platelet aggregation
C) Increased prostacyclin synthesis
D) Increased thromboxane A2 synthesis
Answer: B) Decreased platelet aggregation
Aspirin irreversibly inhibits COX-1 in platelets, preventing
thromboxane A2 formation and reducing platelet aggregation.
,6. A patient presents with gout and is started on allopurinol. What is
the mechanism of action?
A) Xanthine oxidase inhibitor
B) Uricosuric agent
C) Anti-inflammatory
D) Purine synthesis stimulator
Answer: A) Xanthine oxidase inhibitor
Allopurinol inhibits xanthine oxidase, reducing uric acid formation.
7. A man with peptic ulcer disease is prescribed omeprazole. What is
the primary mechanism of action?
A) H2 receptor antagonist
B) Proton pump inhibitor
C) Anticholinergic
D) Mucosal protectant
Answer: B) Proton pump inhibitor
Omeprazole irreversibly inhibits the H+/K+ ATPase in parietal cells,
decreasing gastric acid secretion.
8. A patient develops extrapyramidal symptoms after starting a
psychiatric medication. Which drug class is most likely responsible?
A) SSRIs
B) Typical antipsychotics
C) Benzodiazepines
D) Lithium
Answer: B) Typical antipsychotics
Dopamine D2 receptor blockade in the nigrostriatal pathway by
typical antipsychotics can cause extrapyramidal symptoms.
, 9. A patient is treated with furosemide. Which electrolyte
disturbance is commonly associated?
A) Hyperkalemia
B) Hypokalemia
C) Hypercalcemia
D) Hypermagnesemia
Answer: B) Hypokalemia
Loop diuretics like furosemide increase potassium excretion in the
urine.
10. A patient receiving insulin therapy develops hypoglycemia. Which
of the following is the most appropriate acute treatment?
A) Metformin
B) Glucose
C) Glucagon suppression
D) Sulfonylurea
Answer: B) Glucose
Acute hypoglycemia should be treated immediately with oral or
intravenous glucose.
11. Which drug is used to reverse opioid overdose?
A) Naloxone
B) Naltrexone
C) Methadone
D) Buprenorphine
Answer: A) Naloxone
Naloxone is a competitive opioid antagonist used in acute opioid
toxicity.
Basic Science Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2025/2026 Q&A | Instant Download
1. A 62-year-old man with hypertension is started on a drug that
inhibits angiotensin-converting enzyme (ACE). Which of the following
is a common adverse effect of ACE inhibitors?
A) Hyperkalemia
B) Hypokalemia
C) Hypoglycemia
D) Neutropenia
Answer: A) Hyperkalemia
ACE inhibitors reduce aldosterone secretion, which decreases
potassium excretion, leading to hyperkalemia.
2. A patient is prescribed a selective β1-blocker for hypertension.
Which of the following is a potential side effect?
A) Bronchospasm
B) Bradycardia
C) Hypoglycemia
D) Hyperthyroidism
Answer: B) Bradycardia
Selective β1-blockers decrease heart rate and contractility, which can
result in bradycardia.
3. A 25-year-old woman is treated with a drug that inhibits
dihydrofolate reductase. Which drug is most likely prescribed?
,A) Methotrexate
B) Trimethoprim
C) 5-Fluorouracil
D) Leucovorin
Answer: A) Methotrexate
Methotrexate inhibits dihydrofolate reductase, reducing
tetrahydrofolate levels and impairing DNA synthesis.
4. A patient receiving warfarin therapy develops bleeding. Which
vitamin can be administered as an antidote?
A) Vitamin A
B) Vitamin D
C) Vitamin K
D) Vitamin E
Answer: C) Vitamin K
Vitamin K is required for γ-carboxylation of clotting factors II, VII, IX,
and X; supplementation reverses warfarin anticoagulation.
5. A drug is given that irreversibly inhibits cyclooxygenase-1 (COX-1)
in platelets. Which effect is expected?
A) Increased platelet aggregation
B) Decreased platelet aggregation
C) Increased prostacyclin synthesis
D) Increased thromboxane A2 synthesis
Answer: B) Decreased platelet aggregation
Aspirin irreversibly inhibits COX-1 in platelets, preventing
thromboxane A2 formation and reducing platelet aggregation.
,6. A patient presents with gout and is started on allopurinol. What is
the mechanism of action?
A) Xanthine oxidase inhibitor
B) Uricosuric agent
C) Anti-inflammatory
D) Purine synthesis stimulator
Answer: A) Xanthine oxidase inhibitor
Allopurinol inhibits xanthine oxidase, reducing uric acid formation.
7. A man with peptic ulcer disease is prescribed omeprazole. What is
the primary mechanism of action?
A) H2 receptor antagonist
B) Proton pump inhibitor
C) Anticholinergic
D) Mucosal protectant
Answer: B) Proton pump inhibitor
Omeprazole irreversibly inhibits the H+/K+ ATPase in parietal cells,
decreasing gastric acid secretion.
8. A patient develops extrapyramidal symptoms after starting a
psychiatric medication. Which drug class is most likely responsible?
A) SSRIs
B) Typical antipsychotics
C) Benzodiazepines
D) Lithium
Answer: B) Typical antipsychotics
Dopamine D2 receptor blockade in the nigrostriatal pathway by
typical antipsychotics can cause extrapyramidal symptoms.
, 9. A patient is treated with furosemide. Which electrolyte
disturbance is commonly associated?
A) Hyperkalemia
B) Hypokalemia
C) Hypercalcemia
D) Hypermagnesemia
Answer: B) Hypokalemia
Loop diuretics like furosemide increase potassium excretion in the
urine.
10. A patient receiving insulin therapy develops hypoglycemia. Which
of the following is the most appropriate acute treatment?
A) Metformin
B) Glucose
C) Glucagon suppression
D) Sulfonylurea
Answer: B) Glucose
Acute hypoglycemia should be treated immediately with oral or
intravenous glucose.
11. Which drug is used to reverse opioid overdose?
A) Naloxone
B) Naltrexone
C) Methadone
D) Buprenorphine
Answer: A) Naloxone
Naloxone is a competitive opioid antagonist used in acute opioid
toxicity.
