Pharmacology: Pharmacology: Antibiotics Practice Questions
Test yourself on Pharmacology: Antibiotics with 12 original NCLEX-RN practice questions. Pick an answer to see instant feedback and a full explanation.
Free original practice questions for study purposes. Open Exam Prep is an independent study resource and is not affiliated with, endorsed by, or sponsored by the makers of NCLEX-RN.
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1. A client is started on vancomycin IV for MRSA. During the infusion, the nurse notes flushing of the face and neck, pruritus, and an erythematous rash on the upper body. What is the nurse's priority action?
Explanation. These signs describe vancomycin infusion reaction ('red man syndrome'), caused by histamine release from rapid infusion. The appropriate intervention is to slow the infusion rate (and often give an antihistamine), then resume more slowly. Vancomycin should be infused over at least 60 minutes. Immediately stopping is not first-line for a non-anaphylactic infusion reaction, and shortening future doses would worsen it.
2. A client receiving gentamicin should be monitored most closely for which set of adverse effects?
Explanation. Aminoglycosides like gentamicin are classically associated with nephrotoxicity and ototoxicity. The nurse monitors BUN/creatinine, peak/trough levels, and reports tinnitus, hearing loss, or vertigo. Tendon rupture/QT relate to fluoroquinolones; gingival hyperplasia relates to phenytoin.
3. A client is prescribed oral tetracycline. Which instruction is most important for the nurse to include?
Explanation. Tetracyclines cause photosensitivity, so clients should avoid excessive sun and use protection. Dairy products, antacids, and iron contain calcium/magnesium/aluminum cations that chelate tetracycline and decrease absorption—these should be separated by 1–2 hours. Antibiotics must be completed as prescribed, not stopped when symptoms improve.
4. A client reports a penicillin allergy that caused hives. The provider wants to prescribe an antibiotic. The nurse recognizes that which class carries a potential for cross-sensitivity and should be used cautiously?
Explanation. Cephalosporins share a beta-lactam ring with penicillins, creating a risk of cross-sensitivity (low but real, especially with first-generation cephalosporins). The nurse should report the allergy. Macrolides, fluoroquinolones, and tetracyclines are structurally different and are safer alternatives in penicillin-allergic clients.
5. A client is taking ciprofloxacin (a fluoroquinolone) and reports new calf pain and swelling while walking. What should the nurse do first?
Explanation. Fluoroquinolones carry a black box warning for tendinitis and tendon rupture, especially of the Achilles tendon. New tendon pain warrants stopping the drug, resting the limb, and notifying the provider. Continued activity could precipitate rupture.
6. A client on long-term clindamycin develops severe watery diarrhea, abdominal cramping, and fever. The nurse suspects which complication?
Explanation. Clindamycin and broad-spectrum antibiotics disrupt normal flora and are strongly associated with C. difficile pseudomembranous colitis. The nurse should hold the drug, notify the provider, and obtain a stool sample. Antidiarrheal agents like loperamide are contraindicated because they slow toxin clearance.
7. A nurse is teaching a woman of childbearing age who is prescribed an oral antibiotic along with oral contraceptives. What is the most appropriate teaching?
Explanation. Some antibiotics (notably rifampin, and traditionally broad-spectrum agents) may reduce oral contraceptive effectiveness. The nurse advises using an additional barrier method during therapy. Clients should NOT stop their contraceptive, and antibiotics do not improve contraceptive efficacy.
8. A client receiving IV vancomycin has a trough level drawn. The nurse knows the trough should be obtained at which time?
Explanation. A trough level reflects the lowest drug concentration and is drawn immediately before (within 30 minutes of) the next dose. This ensures therapeutic levels are maintained while avoiding toxicity. A peak would be drawn after the infusion completes.
9. A client is prescribed trimethoprim-sulfamethoxazole (Bactrim). Which statement by the client indicates the need for further teaching?
Explanation. Sulfonamides must be completed as prescribed, not stopped early when symptoms improve, to prevent resistance and incomplete treatment. Adequate fluids prevent crystalluria, reporting rash is essential because of the risk of Stevens-Johnson syndrome, and sunscreen addresses photosensitivity—all correct.
10. A client is to receive an aminoglycoside and is also taking furosemide. The nurse recognizes this combination increases the risk of which toxicity?
Explanation. Both aminoglycosides and loop diuretics like furosemide are ototoxic; using them together significantly increases the risk of hearing loss and balance problems. The nurse should monitor for tinnitus and hearing changes and assess for additive nephrotoxicity as well.
11. A client taking metronidazole for a bacterial infection asks if it is okay to have a glass of wine with dinner. What is the nurse's best response?
Explanation. Metronidazole produces a disulfiram-like reaction with alcohol—flushing, severe nausea, vomiting, palpitations, and headache. Clients must avoid all alcohol (including in mouthwash and certain medications) during therapy and for at least 3 days after.
12. Before administering the first dose of IV ampicillin, which assessment is the nurse's priority?
Explanation. The priority before giving any antibiotic, especially a beta-lactam like ampicillin, is to assess for allergies due to the risk of anaphylaxis. Penicillins are a leading cause of allergic reactions. Diet timing, potassium, and bowel patterns are not priority safety checks for this drug.
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FAQ
How should I memorize antibiotic adverse effects for the NCLEX?
Group drugs by class and link each class to its hallmark adverse effect: aminoglycosides = nephro/ototoxicity, fluoroquinolones = tendon rupture and QT prolongation, tetracyclines/sulfonamides = photosensitivity, vancomycin = red man syndrome with rapid infusion, metronidazole = disulfiram reaction with alcohol. Learning the signature effect per class is more efficient than memorizing individual drugs.
What antibiotic teaching points come up most on the exam?
Common testable points include completing the full course even if symptoms improve, taking on schedule, separating tetracyclines from dairy/antacids/iron, using sunscreen with photosensitizing drugs, avoiding alcohol with metronidazole, using backup contraception, and reporting rash or new tendon pain immediately.
What should I always check before giving any antibiotic?
Always assess for drug allergies first because of the risk of anaphylaxis, particularly with penicillins and cephalosporins. Also confirm the correct drug/dose/route, obtain ordered cultures BEFORE the first dose, and for drugs like vancomycin and aminoglycosides, check renal function and peak/trough levels.