🏥 NCLEX Pharmacology MCQs (101–120) with Answers & Explanations
Pharmacology remains one of the most challenging yet rewarding areas for NCLEX-RN aspirants. In this post, we present NCLEX Pharmacology MCQs Part 3 (101–150), designed to sharpen your drug knowledge and test-taking skills.
This batch covers advanced antibiotic therapy, pain management (opioids & NSAIDs), chemotherapy, psychiatric medications, and critical care drugs. Each question comes with the correct answer and explanation, making it ideal for self-study, revision, and last-minute NCLEX preparation.
If you missed earlier posts, start with 👉 Part 1 (1–50) and Part 2 (51–100).
101. A patient is prescribed gentamicin. Which lab test should the nurse monitor most closely?
A. Liver enzymes
B. Serum potassium
C. Serum creatinine
D. Blood glucose
✅ Answer: C. Serum creatinine
💡 Explanation: Aminoglycosides like gentamicin are nephrotoxic. Kidney function (serum creatinine, BUN) must be monitored to prevent renal damage.
102. A patient receiving vancomycin develops redness and flushing of the upper body. What is this reaction called?
A. Anaphylaxis
B. Red man syndrome
C. Stevens-Johnson syndrome
D. Angioedema
✅ Answer: B. Red man syndrome
💡 Explanation: Red man syndrome occurs when vancomycin is infused too rapidly. It is not an allergic reaction but a histamine release response. Slow IV infusion helps prevent it.
103. Which antibiotic can cause permanent teeth discoloration in children under 8 years?
A. Penicillin
B. Tetracycline
C. Cephalosporin
D. Macrolide
✅ Answer: B. Tetracycline
💡 Explanation: Tetracyclines bind to calcium in teeth and bones, causing yellow-brown discoloration and slowed bone growth in children.
104. A patient on isoniazid (INH) for tuberculosis complains of numbness and tingling in hands and feet. Which vitamin prevents this side effect?
A. Vitamin A
B. Vitamin B6 (pyridoxine)
C. Vitamin C
D. Vitamin D
✅ Answer: B. Vitamin B6 (pyridoxine)
💡 Explanation: INH interferes with pyridoxine metabolism, leading to peripheral neuropathy. Supplementation with vitamin B6 prevents this.
105. Which opioid antagonist is used to reverse respiratory depression?
A. Naloxone
B. Morphine
C. Methadone
D. Buprenorphine
✅ Answer: A. Naloxone
💡 Explanation: Naloxone is a pure opioid antagonist that rapidly reverses the respiratory depression caused by opioid overdose.
106. Which side effect is most common with long-term corticosteroid use?
A. Hypoglycemia
B. Osteoporosis
C. Weight loss
D. Bradycardia
✅ Answer: B. Osteoporosis
💡 Explanation: Long-term corticosteroid therapy causes bone demineralization, hyperglycemia, hypertension, and increased infection risk.
107. A patient taking digoxin reports nausea, blurred vision, and seeing yellow halos. These are signs of:
A. Heart failure
B. Digoxin toxicity
C. Pulmonary edema
D. Liver failure
✅ Answer: B. Digoxin toxicity
💡 Explanation: Classic symptoms of digoxin toxicity include GI upset, visual disturbances (yellow/green halos), and arrhythmias.
108. Which electrolyte imbalance increases the risk of digoxin toxicity?
A. Hyperkalemia
B. Hypokalemia
C. Hypernatremia
D. Hypocalcemia
✅ Answer: B. Hypokalemia
💡 Explanation: Low potassium levels enhance digoxin binding to cardiac tissues, increasing toxicity risk.
109. A nurse should hold a beta-blocker (like metoprolol) if the patient’s heart rate is below:
A. 100 bpm
B. 90 bpm
C. 60 bpm
D. 40 bpm
✅ Answer: C. 60 bpm
💡 Explanation: Beta-blockers slow the heart. If HR < 60 bpm, the drug is withheld and provider notified.
110. Which diuretic causes ototoxicity at high doses?
A. Furosemide
B. Hydrochlorothiazide
C. Spironolactone
D. Acetazolamide
✅ Answer: A. Furosemide
💡 Explanation: Loop diuretics like furosemide may cause hearing loss (ototoxicity), especially with rapid IV administration.
111. A patient taking warfarin should avoid excessive intake of:
A. Vitamin D
B. Vitamin E
C. Vitamin K
D. Vitamin B12
✅ Answer: C. Vitamin K
💡 Explanation: Vitamin K is the antidote to warfarin. Excessive dietary intake (leafy greens) reduces warfarin effectiveness.
112. Which lab test monitors warfarin therapy?
A. aPTT
B. PT/INR
C. Platelet count
D. Fibrinogen
✅ Answer: B. PT/INR
💡 Explanation: Prothrombin Time (PT) and International Normalized Ratio (INR) monitor warfarin therapy. Target INR = 2.0–3.0.
113. Heparin therapy is best monitored using:
A. PT
B. INR
C. aPTT
D. Platelet count
✅ Answer: C. aPTT
💡 Explanation: Activated Partial Thromboplastin Time (aPTT) measures heparin activity.
114. Which drug is the antidote for heparin overdose?
A. Vitamin K
B. Protamine sulfate
C. Naloxone
D. Atropine
✅ Answer: B. Protamine sulfate
💡 Explanation: Protamine sulfate binds to heparin, neutralizing its anticoagulant effect.
115. A patient taking lithium for bipolar disorder must avoid:
A. Excessive water intake
B. High salt intake
C. Low salt intake
D. Dairy products
✅ Answer: C. Low salt intake
💡 Explanation: Low sodium levels increase lithium reabsorption, raising risk of toxicity. Patients must maintain normal salt intake.
116. Which antidepressant carries a risk of hypertensive crisis with tyramine-rich foods?
A. SSRIs
B. MAO inhibitors
C. Tricyclics
D. SNRIs
✅ Answer: B. MAO inhibitors
💡 Explanation: MAO inhibitors (e.g., phenelzine, tranylcypromine) interact with tyramine foods (cheese, wine), causing dangerous hypertension.
117. Which antipsychotic is most associated with agranulocytosis?
A. Haloperidol
B. Clozapine
C. Risperidone
D. Olanzapine
✅ Answer: B. Clozapine
💡 Explanation: Clozapine requires weekly WBC monitoring due to risk of agranulocytosis (life-threatening low WBC count).
118. Which insulin has the fastest onset of action?
A. Regular insulin
B. NPH insulin
C. Insulin lispro
D. Insulin glargine
✅ Answer: C. Insulin lispro
💡 Explanation: Insulin lispro (rapid-acting) starts working in 15 minutes and is used before meals.
119. A nurse should monitor for lactic acidosis in a patient taking:
A. Metformin
B. Insulin glargine
C. Glyburide
D. Sitagliptin
✅ Answer: A. Metformin
💡 Explanation: Metformin carries a rare but serious risk of lactic acidosis, especially with renal impairment.
120. Which thyroid medication is safe in pregnancy?
A. Methimazole
B. Levothyroxine
C. Radioactive iodine
D. None of these
✅ Answer: B. Levothyroxine
💡 Explanation: Levothyroxine (synthetic T4) is safe and essential for hypothyroid pregnant women. Methimazole & radioactive iodine are contraindicated.
121. Which antiepileptic drug can cause gingival hyperplasia?
A. Valproic acid
B. Phenytoin
C. Carbamazepine
D. Lamotrigine
✅ Answer: B. Phenytoin
💡 Explanation: Long-term phenytoin use causes gum overgrowth (gingival hyperplasia) and requires good oral hygiene.
122. A nurse is teaching a patient on carbamazepine. Which precaution is most important?
A. Avoid dairy products
B. Monitor for skin rash
C. Increase vitamin K intake
D. Avoid salt substitutes
✅ Answer: B. Monitor for skin rash
💡 Explanation: Carbamazepine can cause Stevens-Johnson syndrome (SJS), especially in Asian patients with HLA-B*1502 allele.
123. Which drug is contraindicated with sildenafil (Viagra)?
A. Aspirin
B. Nitrates
C. Beta-blockers
D. Antacids
✅ Answer: B. Nitrates
💡 Explanation: Sildenafil + nitrates can cause life-threatening hypotension.
124. A patient taking rifampin for TB should be informed about which harmless side effect?
A. Blue urine
B. Red-orange urine and tears
C. White patches in mouth
D. Metallic taste
✅ Answer: B. Red-orange urine and tears
💡 Explanation: Rifampin causes orange-red body fluids (urine, sweat, saliva, tears). It is harmless but important to warn patients.
125. Which TB drug can cause optic neuritis leading to vision changes?
A. Isoniazid
B. Rifampin
C. Ethambutol
D. Pyrazinamide
✅ Answer: C. Ethambutol
💡 Explanation: Ethambutol may damage the optic nerve, leading to color blindness and blurred vision.
126. Which medication is used in alcohol withdrawal to prevent seizures?
A. Diazepam
B. Disulfiram
C. Naltrexone
D. Methadone
✅ Answer: A. Diazepam
💡 Explanation: Benzodiazepines (diazepam, lorazepam) prevent seizures and ease withdrawal symptoms in alcohol detox.
127. Disulfiram is used to treat alcohol dependence by causing:
A. Intense cravings
B. Severe reaction with alcohol intake
C. Improved liver function
D. Reduced anxiety
✅ Answer: B. Severe reaction with alcohol intake
💡 Explanation: Disulfiram causes flushing, nausea, palpitations, hypotension when alcohol is consumed → deters drinking.
128. Which drug is used as opioid substitution therapy?
A. Methadone
B. Diazepam
C. Buprenorphine
D. Both A & C
✅ Answer: D. Both A & C
💡 Explanation: Methadone and buprenorphine are used in maintenance therapy to reduce opioid cravings and withdrawal symptoms.
129. Which cholesterol-lowering drug can cause muscle pain (myopathy)?
A. Statins (atorvastatin)
B. Niacin
C. Bile acid resins
D. Fibrates
✅ Answer: A. Statins (atorvastatin)
💡 Explanation: Statins may cause rhabdomyolysis and liver toxicity. Monitor CK levels if patient reports muscle pain.
130. Which vitamin should be taken with isoniazid (INH) to prevent neuropathy?
A. Vitamin B1
B. Vitamin B6
C. Vitamin B12
D. Vitamin D
✅ Answer: B. Vitamin B6
💡 Explanation: INH depletes pyridoxine (B6) leading to peripheral neuropathy. Supplementation prevents complications.
131. Which antimalarial drug is also used for autoimmune diseases like lupus?
A. Chloroquine
B. Artemisinin
C. Primaquine
D. Mefloquine
✅ Answer: A. Chloroquine
💡 Explanation: Chloroquine is used for malaria and autoimmune disorders (lupus, rheumatoid arthritis).
132. Which vaccine should not be given to immunocompromised patients?
A. Influenza (inactivated)
B. MMR
C. Hepatitis B
D. Tetanus
✅ Answer: B. MMR
💡 Explanation: Live vaccines (MMR, Varicella, Oral polio) are contraindicated in immunocompromised patients.
133. Which antibiotic is contraindicated in pregnancy due to cartilage damage risk in fetus?
A. Penicillin
B. Ciprofloxacin
C. Azithromycin
D. Amoxicillin
✅ Answer: B. Ciprofloxacin
💡 Explanation: Fluoroquinolones (ciprofloxacin) are avoided in pregnancy because they may damage cartilage and joints in the fetus.
134. Which anticoagulant is safe in pregnancy?
A. Warfarin
B. Heparin
C. Dabigatran
D. Rivaroxaban
✅ Answer: B. Heparin
💡 Explanation: Heparin does not cross the placenta and is the anticoagulant of choice in pregnancy, unlike warfarin.
135. Which electrolyte should be monitored in patients on ACE inhibitors (like lisinopril)?
A. Sodium
B. Potassium
C. Calcium
D. Magnesium
✅ Answer: B. Potassium
💡 Explanation: ACE inhibitors may cause hyperkalemia by decreasing aldosterone activity.
136. A patient taking spironolactone should avoid:
A. Bananas and oranges
B. High-protein diet
C. Dairy products
D. Whole grains
✅ Answer: A. Bananas and oranges
💡 Explanation: Spironolactone is a potassium-sparing diuretic. Avoid potassium-rich foods to prevent hyperkalemia.
137. Which drug is used as first-line treatment for status epilepticus?
A. Phenytoin
B. Diazepam
C. Valproic acid
D. Gabapentin
✅ Answer: B. Diazepam
💡 Explanation: IV benzodiazepines (diazepam or lorazepam) are first-line in acute seizure emergencies.
138. Which thyroid drug is contraindicated in pregnancy?
A. Levothyroxine
B. Methimazole
C. Propylthiouracil (PTU)
D. None of these
✅ Answer: B. Methimazole
💡 Explanation: Methimazole is teratogenic in 1st trimester → PTU is preferred early in pregnancy.
139. Which diabetic medication can cause hypoglycemia if taken without food?
A. Metformin
B. Insulin
C. Sulfonylureas (glipizide)
D. DPP-4 inhibitors
✅ Answer: C. Sulfonylureas (glipizide)
💡 Explanation: Sulfonylureas stimulate insulin release regardless of meals → risk of severe hypoglycemia.
140. Which drug is used to prevent organ transplant rejection?
A. Methotrexate
B. Cyclosporine
C. Prednisone
D. Rituximab
✅ Answer: B. Cyclosporine
💡 Explanation: Cyclosporine suppresses T-cell activity and prevents rejection in organ transplantation.
141. Which insulin has the fastest onset of action?
A. Regular insulin
B. Lispro
C. NPH
D. Glargine
✅ Answer: B. Lispro
💡 Explanation: Lispro (rapid-acting) works within 15 minutes, making it suitable for controlling post-meal blood glucose spikes.
142. Which insulin cannot be mixed with any other type?
A. Lispro
B. NPH
C. Glargine
D. Regular insulin
✅ Answer: C. Glargine
💡 Explanation: Glargine (long-acting insulin) must never be mixed with other insulins because of its unique pH and release mechanism.
143. Which drug is commonly used for prophylaxis of migraine?
A. Sumatriptan
B. Propranolol
C. Ergotamine
D. Ibuprofen
✅ Answer: B. Propranolol
💡 Explanation: Beta-blockers (like propranolol) are used for migraine prevention, while triptans are used for acute attacks.
144. A nurse should monitor INR values in a patient taking which drug?
A. Aspirin
B. Warfarin
C. Heparin
D. Dabigatran
✅ Answer: B. Warfarin
💡 Explanation: Warfarin therapy requires monitoring of INR (2.0–3.0) to prevent bleeding or clotting risks.
145. Which drug is the antidote for heparin overdose?
A. Vitamin K
B. Protamine sulfate
C. Fresh frozen plasma
D. Activated charcoal
✅ Answer: B. Protamine sulfate
💡 Explanation: Protamine sulfate binds heparin and neutralizes its anticoagulant effect.
146. Which antiplatelet drug irreversibly inhibits platelet aggregation?
A. Clopidogrel
B. Aspirin
C. Both A & B
D. Warfarin
✅ Answer: C. Both A & B
💡 Explanation: Aspirin (COX inhibitor) and clopidogrel (ADP receptor blocker) both irreversibly inhibit platelets.
147. Which drug is first-line for acute asthma attack?
A. Salmeterol
B. Albuterol
C. Theophylline
D. Montelukast
✅ Answer: B. Albuterol
💡 Explanation: Albuterol (short-acting beta-2 agonist) provides rapid relief in acute bronchospasm.
148. Which drug class can cause a dry cough as a side effect?
A. Beta-blockers
B. ACE inhibitors
C. Calcium channel blockers
D. ARBs
✅ Answer: B. ACE inhibitors
💡 Explanation: ACE inhibitors increase bradykinin levels → persistent dry cough in some patients.
149. Which antibiotic may cause permanent teeth discoloration in children?
A. Amoxicillin
B. Tetracycline
C. Azithromycin
D. Ceftriaxone
✅ Answer: B. Tetracycline
💡 Explanation: Tetracyclines bind calcium → cause yellow/brown tooth discoloration in children and pregnant women.
150. Which medication is given to treat malignant hyperthermia?
A. Dantrolene
B. Atropine
C. Naloxone
D. Flumazenil
✅ Answer: A. Dantrolene
💡 Explanation: Dantrolene is a muscle relaxant that treats malignant hyperthermia, a rare but fatal reaction to anesthesia.
You’ve just completed NCLEX Pharmacology MCQs Part 3 (101–150) ✅. These practice questions help you master drug actions, side effects, interactions, and nursing considerations—skills essential for safe nursing practice.
📌 What’s Next?
- Revise all 150 pharmacology MCQs we’ve covered so far.
- 👉 NCLEX Pharmacology Part 4 (151–200) with more advanced questions.
- Explore our Anatomy, Physiology, and Microbiology MCQs for complete NCLEX coverage.
💡 Pro Tip: Consistent practice with MCQs + explanations is the fastest way to build confidence for the NCLEX exam.