Medication interactions NCLEX-RN Practice Questions

Medication interactions NCLEX-RN Practice Questions

by

Medication interactions NCLEX-RN Practice Questions help you refine clinical judgment around one of the most testable and safety-critical topics in Pharmacological & Parenteral Therapies. Nurses must anticipate, recognize, and respond to drug–drug, drug–food, and drug–herbal interactions to prevent adverse events. This set dives into real NCLEX-RN level scenarios where a single interaction can change outcomes—warfarin and antibiotics, MAOIs and tyramine, IV incompatibilities, serotonin syndrome risks, electrolyte-driven toxicity, and more. Each question emphasizes prioritization, client education, monitoring, and safe administration. Use these to sharpen your ability to connect medication mechanisms with practical bedside decisions, anticipate lab changes, and deliver precise client counseling to minimize harm and optimize therapeutic effects.

Q1. A client on chronic warfarin therapy for atrial fibrillation is prescribed trimethoprim–sulfamethoxazole for a UTI. What is the nurse’s priority action?

  • Notify the provider and anticipate a reduced warfarin dose with earlier INR recheck
  • Hold the antibiotic and request a different class
  • Increase dietary vitamin K intake to offset the interaction
  • Administer both medications as ordered and recheck INR in one month

Correct Answer: Notify the provider and anticipate a reduced warfarin dose with earlier INR recheck

Q2. A client taking phenelzine reports using an over-the-counter cold medicine. Which ingredient would most concern the nurse due to interaction risk?

  • Dextromethorphan
  • Guaifenesin
  • Pseudoephedrine
  • Saline nasal spray

Correct Answer: Pseudoephedrine

Q3. A client on linezolid therapy also takes sertraline. Which assessment finding requires immediate intervention?

  • Blood pressure 98/60 mm Hg
  • Muscle rigidity and hyperreflexia
  • Mild nausea after meals
  • Scattered petechiae on the forearms

Correct Answer: Muscle rigidity and hyperreflexia

Q4. A client receiving digoxin and furosemide is at increased risk of toxicity due to which interaction mechanism?

  • Loop diuretics cause hyperkalemia, increasing digoxin binding
  • Loop diuretics cause hypokalemia, increasing digoxin sensitivity
  • Loop diuretics increase digoxin clearance, reducing effect
  • Loop diuretics alkalinize urine, decreasing digoxin levels

Correct Answer: Loop diuretics cause hypokalemia, increasing digoxin sensitivity

Q5. The nurse teaches a client on levothyroxine about medication timing. Which instruction prevents a common interaction that reduces absorption?

  • “Take with calcium carbonate to reduce stomach upset.”
  • “Take with breakfast for best absorption.”
  • “Separate from iron or calcium supplements by at least 4 hours.”
  • “Take with antacids if heartburn occurs.”

Correct Answer: “Separate from iron or calcium supplements by at least 4 hours.”

Q6. A client on lisinopril is started on spironolactone. What is the nurse’s highest priority monitoring focus?

  • Hyponatremia
  • Hyperkalemia
  • Hypocalcemia
  • Hypomagnesemia

Correct Answer: Hyperkalemia

Q7. The nurse reviews medications for a client taking warfarin. Which herbal supplement requires immediate teaching due to bleeding risk?

  • Ginkgo biloba
  • Ginger capsules
  • Glucosamine
  • Garlic tablets

Correct Answer: Garlic tablets

Q8. A client on simvastatin asks about drinking grapefruit juice. What is the appropriate response?

  • “Limit to one glass per week.”
  • “Avoid grapefruit juice; it can raise simvastatin levels and increase muscle injury risk.”
  • “Drink only with meals to reduce interaction.”
  • “Switch to orange juice on days you take the statin.”

Correct Answer: “Avoid grapefruit juice; it can raise simvastatin levels and increase muscle injury risk.”

Q9. A client taking warfarin is prescribed metronidazole for bacterial vaginosis. Which plan is best?

  • Advise increased vitamin K intake during therapy
  • Hold warfarin for 48 hours after starting metronidazole
  • Notify provider to anticipate increased INR and arrange earlier monitoring
  • Switch metronidazole to amoxicillin to avoid interaction

Correct Answer: Notify provider to anticipate increased INR and arrange earlier monitoring

Q10. A client on haloperidol is prescribed erythromycin. Which complication is the priority concern?

  • Severe hypotension
  • QT prolongation leading to torsades de pointes
  • Neuroleptic malignant syndrome
  • Cholestatic jaundice

Correct Answer: QT prolongation leading to torsades de pointes

Q11. A client using nitroglycerin for angina is given sildenafil for erectile dysfunction. What is the nurse’s action?

  • Administer both and monitor blood pressure hourly
  • Hold sildenafil and notify the provider due to severe hypotension risk
  • Administer with food to blunt vasodilation
  • Space the drugs by 4 hours to avoid interaction

Correct Answer: Hold sildenafil and notify the provider due to severe hypotension risk

Q12. A client on lithium for bipolar disorder is self-treating osteoarthritis with ibuprofen. What is the nurse’s best instruction?

  • “Use acetaminophen instead of NSAIDs to avoid lithium accumulation.”
  • “Add aspirin to balance the NSAID effect on lithium.”
  • “Increase lithium dose if pain worsens.”
  • “No changes are needed; these drugs are safe together.”

Correct Answer: “Use acetaminophen instead of NSAIDs to avoid lithium accumulation.”

Q13. A client taking fluoxetine reports poor pain control with codeine. Which explanation is most accurate?

  • Fluoxetine induces hepatic enzymes increasing codeine activation
  • Fluoxetine inhibits CYP2D6 reducing codeine’s conversion to morphine
  • Fluoxetine increases P-glycoprotein pumping codeine into the brain
  • Fluoxetine alkalinizes urine prolonging codeine effect

Correct Answer: Fluoxetine inhibits CYP2D6 reducing codeine’s conversion to morphine

Q14. A client on clopidogrel is prescribed omeprazole. What is the priority nursing action?

  • Administer both as ordered; no interaction is expected
  • Notify the provider because omeprazole may reduce clopidogrel activation
  • Switch clopidogrel to warfarin
  • Hold omeprazole and give an H2 blocker without provider consultation

Correct Answer: Notify the provider because omeprazole may reduce clopidogrel activation

Q15. The nurse prepares IV phenytoin for a client with seizures. Which action prevents a critical compatibility error?

  • Dilute in 5% dextrose only
  • Administer undiluted via Y-site with any compatible solution
  • Dilute in normal saline only and use a dedicated line
  • Mix with enteral formula to prevent hypotension

Correct Answer: Dilute in normal saline only and use a dedicated line

Q16. A client starting rifampin asks about birth control. Which teaching is correct?

  • “Rifampin increases oral contraceptive effectiveness.”
  • “Use a nonhormonal backup method; rifampin reduces contraceptive efficacy.”
  • “Switch to a higher-dose estrogen pill.”
  • “No changes are needed with rifampin.”

Correct Answer: “Use a nonhormonal backup method; rifampin reduces contraceptive efficacy.”

Q17. A client on warfarin begins eating large amounts of spinach and kale. What change should the nurse anticipate?

  • Decreased INR and reduced anticoagulant effect
  • Increased INR and bleeding risk
  • No change in INR
  • Elevated liver enzymes

Correct Answer: Decreased INR and reduced anticoagulant effect

Q18. A client on venlafaxine uses sumatriptan for migraines. Which symptom suggests a significant interaction?

  • Constipation and dry mouth
  • Bradycardia and miosis
  • Agitation, diaphoresis, and tremor
  • Rash and conjunctivitis

Correct Answer: Agitation, diaphoresis, and tremor

Q19. A client receiving gentamicin and furosemide requires which priority monitoring due to interaction risk?

  • Ototoxicity and renal function
  • Hepatotoxicity
  • Hyperglycemia
  • Platelet count

Correct Answer: Ototoxicity and renal function

Q20. A neonate is ordered IV ceftriaxone and calcium gluconate. The nurse should:

  • Administer via Y-site to maintain IV access
  • Administer ceftriaxone in a separate line and avoid concomitant calcium due to precipitation risk
  • Administer calcium first to protect cardiac function
  • Mix both in the same syringe for rapid delivery

Correct Answer: Administer ceftriaxone in a separate line and avoid concomitant calcium due to precipitation risk

Q21. A client on theophylline is prescribed ciprofloxacin. Which is the best nursing action?

  • Administer both and schedule a trough level in 6 weeks
  • Notify the provider; ciprofloxacin can increase theophylline levels
  • Switch ciprofloxacin to levofloxacin without order
  • Increase theophylline dose to maintain bronchodilation

Correct Answer: Notify the provider; ciprofloxacin can increase theophylline levels

Q22. A client on methadone for chronic pain is prescribed levofloxacin. What is the major interaction concern?

  • Severe constipation
  • Serotonin syndrome
  • QT prolongation and torsades risk
  • Acute angle-closure glaucoma

Correct Answer: QT prolongation and torsades risk

Q23. A client taking MAOIs asks about safe dietary choices. Which food requires avoidance due to interaction?

  • Fresh cottage cheese
  • Aged cheddar
  • Fresh apples
  • Pasteurized milk

Correct Answer: Aged cheddar

Q24. A client on insulin and a nonselective beta-blocker (propranolol) has episodes of hypoglycemia. What critical teaching should the nurse provide?

  • “Beta-blockers can mask hypoglycemia tremors and tachycardia; monitor glucose closely.”
  • “Propranolol prevents hypoglycemia.”
  • “Take extra insulin to counter stress.”
  • “Switch to long-acting insulin to avoid interactions.”

Correct Answer: “Beta-blockers can mask hypoglycemia tremors and tachycardia; monitor glucose closely.”

Q25. A client receiving heparin is also prescribed aspirin. Which rationale supports a provider consultation?

  • Heparin inhibits platelet aggregation by COX-1 blockade
  • Combined heparin and aspirin increases bleeding risk via complementary mechanisms
  • Aspirin lowers heparin levels
  • Heparin reverses aspirin’s effects

Correct Answer: Combined heparin and aspirin increases bleeding risk via complementary mechanisms

Q26. A client takes cyclosporine after transplant and drinks grapefruit juice daily. What is the priority teaching?

  • “Grapefruit juice lowers cyclosporine levels.”
  • “Avoid grapefruit juice; it can raise cyclosporine levels and increase nephrotoxicity.”
  • “Drink with milk to reduce interactions.”
  • “Increase fluid intake to offset the effect.”

Correct Answer: “Avoid grapefruit juice; it can raise cyclosporine levels and increase nephrotoxicity.”

Q27. A client on carbamazepine is counseled about contraception. Which statement by the client indicates understanding?

  • “My pill will work better with carbamazepine.”
  • “I need a backup nonhormonal method because carbamazepine reduces pill effectiveness.”
  • “I’ll take double the estrogen dose to compensate.”
  • “No backup is necessary.”

Correct Answer: “I need a backup nonhormonal method because carbamazepine reduces pill effectiveness.”

Q28. A client on vancomycin is started on piperacillin–tazobactam. The nurse should prioritize monitoring for:

  • Nephrotoxicity with rising creatinine
  • Hyperkalemia
  • Thrombocytosis
  • Hypercalcemia

Correct Answer: Nephrotoxicity with rising creatinine

Q29. A client receiving enteral tube feeds is prescribed oral phenytoin. What is the best administration plan to prevent interaction?

  • Crush and mix phenytoin into the feeding bag
  • Stop feeds 1–2 hours before and after dosing and flush the tube well
  • Dilute phenytoin in milk for better absorption
  • Give with high-protein formula to enhance binding

Correct Answer: Stop feeds 1–2 hours before and after dosing and flush the tube well

Q30. A client treated with metronidazole asks about alcohol use. What is the appropriate response regarding interaction?

  • “Alcohol is safe in moderation.”
  • “Limit to one drink per day.”
  • “Avoid alcohol during therapy and for 48–72 hours after to prevent a disulfiram-like reaction.”
  • “Drink with meals to avoid flushing.”

Correct Answer: “Avoid alcohol during therapy and for 48–72 hours after to prevent a disulfiram-like reaction.”

Leave a Comment