Comprehensive RN Pharmacology Exam Preparation: 150 Practice
Questions with Verified Answers and Detailed Rationales Covering
Antibiotics, Cardiac Drugs, Anticoagulants, Insulin, Diuretics,
Psychiatric Medications, Pain Management, and Emergency
Antidotes for NCLEX Success.
150 Pharmacology Questions – Answers &
Explanations
Section 1: Antibiotics (Questions 1–15)
1. A patient on IV vancomycin reports flushing, rash on the neck
and chest, and hypotension. What is the priority action?
A. Slow the infusion rate
B. Give diphenhydramine
C. Stop the infusion immediately
D. Notify the provider
Answer: C – This is Red Man Syndrome. Stop infusion first, then
treat.
2. Which lab finding requires holding the next dose of
gentamicin?
A. Cr 0.8 mg/dL
B. BUN 15 mg/dL
C. Trough level 3.5 mcg/mL
,D. Peak level 6 mcg/mL
Answer: C – High trough (>2 mcg/mL) indicates toxicity risk.
3. A patient allergic to penicillin is prescribed cephalexin. What
action is correct?
A. Give as ordered; cross-reactivity is a myth
B. Hold and notify provider; up to 10% cross-reactivity
C. Administer with an antihistamine
D. Give a test dose first
Answer: B – Cross-reactivity risk is real; avoid unless necessary.
4. Which antibiotic causes red-brown discoloration of body
fluids?
A. Ciprofloxacin
B. Doxycycline
C. Rifampin
D. Metronidazole
Answer: C – Rifampin turns urine, sweat, tears orange-red;
harmless.
5. A patient on linezolid reports headache, palpitations, and
sweating after eating cheese. What happened?
A. Anaphylaxis
B. Hypertensive crisis (tyramine interaction)
C. Serotonin syndrome
D. Linezolid toxicity
Answer: B – Linezolid is an MAOI; avoid aged cheese, wine, cured
meats.
6. Which instruction is correct for tetracycline?
A. Take with milk or antacids
B. Take on an empty stomach with water
,C. Expect tooth discoloration in adults
D. May cause weight gain
Answer: B – Dairy and antacids bind tetracycline, reducing
absorption.
7. A patient has C. difficile diarrhea after clindamycin. What drug
is first-line?
A. Metronidazole
B. Vancomycin (oral)
C. Fidaxomicin
D. IV metronidazole
Answer: B – Oral vancomycin or fidaxomicin is now preferred over
metronidazole.
8. Which fluoroquinolone side effect requires immediate
discontinuation?
A. Nausea
B. Dizziness
C. Tendon pain
D. Photosensitivity
Answer: C – Risk of tendon rupture; hold and notify provider.
9. A sulfa-allergic patient should avoid:
A. Penicillin G
B. Azithromycin
C. Trimethoprim-sulfamethoxazole
D. Doxycycline
Answer: C – Bactrim/Septra contains sulfa.
10. Which drug requires a loading dose for meningitis but not for
UTI?
A. Ceftriaxone
, B. Ciprofloxacin
C. Vancomycin
D. Gentamicin
Answer: A – Ceftriaxone loading dose for severe infections.
11. Macrolides like azithromycin prolong which cardiac interval?
A. PR interval
B. QRS duration
C. QT interval
D. ST segment
Answer: C – Risk of torsades de pointes.
12. A patient on metronidazole drinks alcohol and now has severe
nausea, vomiting, and flushing. This is:
A. Disulfiram-like reaction
B. Anaphylaxis
C. Serotonin toxicity
D. Alcohol withdrawal
Answer: A – Avoid alcohol during and for 48 hours after
metronidazole.
13. Which antibiotic is safe in pregnancy?
A. Doxycycline
B. Ciprofloxacin
C. Amoxicillin
D. Gentamicin
Answer: C – Penicillins are pregnancy category B.
14. A patient gets IV aztreonam. It is most similar to which drug
class?
A. Penicillins
B. Carbapenems
Questions with Verified Answers and Detailed Rationales Covering
Antibiotics, Cardiac Drugs, Anticoagulants, Insulin, Diuretics,
Psychiatric Medications, Pain Management, and Emergency
Antidotes for NCLEX Success.
150 Pharmacology Questions – Answers &
Explanations
Section 1: Antibiotics (Questions 1–15)
1. A patient on IV vancomycin reports flushing, rash on the neck
and chest, and hypotension. What is the priority action?
A. Slow the infusion rate
B. Give diphenhydramine
C. Stop the infusion immediately
D. Notify the provider
Answer: C – This is Red Man Syndrome. Stop infusion first, then
treat.
2. Which lab finding requires holding the next dose of
gentamicin?
A. Cr 0.8 mg/dL
B. BUN 15 mg/dL
C. Trough level 3.5 mcg/mL
,D. Peak level 6 mcg/mL
Answer: C – High trough (>2 mcg/mL) indicates toxicity risk.
3. A patient allergic to penicillin is prescribed cephalexin. What
action is correct?
A. Give as ordered; cross-reactivity is a myth
B. Hold and notify provider; up to 10% cross-reactivity
C. Administer with an antihistamine
D. Give a test dose first
Answer: B – Cross-reactivity risk is real; avoid unless necessary.
4. Which antibiotic causes red-brown discoloration of body
fluids?
A. Ciprofloxacin
B. Doxycycline
C. Rifampin
D. Metronidazole
Answer: C – Rifampin turns urine, sweat, tears orange-red;
harmless.
5. A patient on linezolid reports headache, palpitations, and
sweating after eating cheese. What happened?
A. Anaphylaxis
B. Hypertensive crisis (tyramine interaction)
C. Serotonin syndrome
D. Linezolid toxicity
Answer: B – Linezolid is an MAOI; avoid aged cheese, wine, cured
meats.
6. Which instruction is correct for tetracycline?
A. Take with milk or antacids
B. Take on an empty stomach with water
,C. Expect tooth discoloration in adults
D. May cause weight gain
Answer: B – Dairy and antacids bind tetracycline, reducing
absorption.
7. A patient has C. difficile diarrhea after clindamycin. What drug
is first-line?
A. Metronidazole
B. Vancomycin (oral)
C. Fidaxomicin
D. IV metronidazole
Answer: B – Oral vancomycin or fidaxomicin is now preferred over
metronidazole.
8. Which fluoroquinolone side effect requires immediate
discontinuation?
A. Nausea
B. Dizziness
C. Tendon pain
D. Photosensitivity
Answer: C – Risk of tendon rupture; hold and notify provider.
9. A sulfa-allergic patient should avoid:
A. Penicillin G
B. Azithromycin
C. Trimethoprim-sulfamethoxazole
D. Doxycycline
Answer: C – Bactrim/Septra contains sulfa.
10. Which drug requires a loading dose for meningitis but not for
UTI?
A. Ceftriaxone
, B. Ciprofloxacin
C. Vancomycin
D. Gentamicin
Answer: A – Ceftriaxone loading dose for severe infections.
11. Macrolides like azithromycin prolong which cardiac interval?
A. PR interval
B. QRS duration
C. QT interval
D. ST segment
Answer: C – Risk of torsades de pointes.
12. A patient on metronidazole drinks alcohol and now has severe
nausea, vomiting, and flushing. This is:
A. Disulfiram-like reaction
B. Anaphylaxis
C. Serotonin toxicity
D. Alcohol withdrawal
Answer: A – Avoid alcohol during and for 48 hours after
metronidazole.
13. Which antibiotic is safe in pregnancy?
A. Doxycycline
B. Ciprofloxacin
C. Amoxicillin
D. Gentamicin
Answer: C – Penicillins are pregnancy category B.
14. A patient gets IV aztreonam. It is most similar to which drug
class?
A. Penicillins
B. Carbapenems
