Pharmacology Practice Test #7: Antibiotics and Antimicrobials

Answer: C. Hold the next dose, have the client rest the leg, and notify the provider promptly

Rationale: Fluoroquinolones such as levofloxacin and ciprofloxacin carry a boxed warning for tendinitis and tendon rupture, most often of the Achilles tendon. The risk is higher in older adults, in clients taking corticosteroids such as prednisone, and after kidney, heart or lung transplant. New tendon pain or swelling is a sign to stop the drug: the nurse holds the next dose, has the client rest the limb and avoid exercise, and notifies the provider so a different antibiotic can be chosen. Option A is wrong because continuing the drug can lead to rupture. Option B is wrong because activity puts more strain on an inflamed tendon. Option D is wrong because tendon damage is not expected, and it can even appear after the course has ended.

Answer: A. "I'll take each capsule with just a sip of water right before I lie down for bed."

Rationale: Option A shows a need for more teaching. Doxycycline that is taken with too little water, or just before lying down, can stick in the esophagus and cause painful esophagitis and ulcers. The client should take each dose with a full glass of water and stay upright afterward, so option B is correct teaching. Option C is correct because tetracyclines increase sensitivity to sunlight and sunburn. Option D is correct because antacids, calcium, iron and other minerals bind tetracyclines and reduce absorption, so they are taken at a different time, with the spacing set by the pharmacist or prescriber.

Answer: D. "Avoid all alcohol, including mouthwash and cough syrups that contain alcohol, during treatment and for at least 3 days after your last dose."

Rationale: Metronidazole interferes with the breakdown of alcohol. Drinking alcohol while taking it can cause a disulfiram-like reaction: flushing, abdominal cramps, nausea and vomiting, headache and a fast heart rate. The product labeling advises avoiding alcohol during treatment and for at least 3 days after the last dose, and clients are often unaware that some mouthwashes and liquid cold medicines contain alcohol. Option A is wrong because metronidazole may be taken with food to lessen stomach upset and the metallic taste it often causes. Option B is wrong because stopping early can lead to treatment failure; the client finishes the prescribed course. Option C is wrong because routine antacid use is not part of metronidazole teaching.

Answer: B. Place the client on contact precautions per facility policy and notify the provider so stool testing for C. difficile can be ordered

Rationale: Clindamycin is one of the antibiotics most often linked to Clostridioides difficile infection, and new frequent watery stools with cramping and fever during antibiotic therapy should be treated as possible C. difficile until testing says otherwise. The nurse starts contact precautions according to facility policy (with soap-and-water hand hygiene, because alcohol rubs do not kill the spores) and notifies the provider, who orders the stool test and decides about the clindamycin and any treatment. Option A is wrong because antimotility drugs are generally avoided when C. difficile is suspected, as they can hold toxin in the bowel. Option C is wrong because waiting delays diagnosis and lets the infection spread to other clients. Option D is wrong because the lab tests only loose, unformed stool for C. difficile.

Answer: B. Fever, a spreading red rash with blisters, and painful sores in the mouth

Rationale: Sulfonamides such as sulfamethoxazole-trimethoprim are a known cause of Stevens-Johnson syndrome and toxic epidermal necrolysis, severe reactions in which the skin and mucous membranes blister and peel. Fever with a spreading blistering rash and mouth sores is an emergency: the client must stop the drug and be seen right away. Option A is a common, minor effect that usually improves when the drug is taken with food. Option C calls for teaching about drinking enough fluid, which also lowers the risk of crystals forming in the urine, but it is not the most urgent. Option D is a minor complaint that has resolved.

Answer: C. Agitation, tremor, heavy sweating, a temperature of 38.6 °C (101.5 °F), and muscle twitching

Rationale: Linezolid is an antibiotic that also weakly inhibits monoamine oxidase (MAO). Given with serotonergic drugs such as SSRIs, it can cause serotonin syndrome: agitation or confusion, tremor, sweating, fever, a fast heart rate, and muscle twitching or rigidity. This can become life-threatening, so the nurse reports it immediately; the provider decides whether to stop one of the drugs and how to treat. Clients on linezolid are also taught to limit foods very high in tyramine. Options A, B and D describe mild or expected effects that do not point to serotonin toxicity.

Answer: A. "Take out your dentures, then swish the medicine around your whole mouth for as long as you can before you swallow it."

Rationale: Nystatin works by direct contact with the yeast and is barely absorbed from the gut, so it must stay in contact with the lining of the mouth. The client removes the dentures, swishes the suspension around the whole mouth and holds it there as long as possible, then swallows (or spits, if that is what the prescription says). Dentures are cleaned and treated as well, or the infection can return. The dose is usually taken after meals and other mouth care. Option B is wrong because diluting it in a drink washes it past the mouth. Option C is wrong because rinsing right away removes the drug. Option D is wrong because the client continues for the full prescribed time, which often extends past the point the patches disappear.

Answer: D. Keep the client well hydrated as prescribed and monitor urine output, BUN and creatinine

Rationale: IV acyclovir can form crystals in the kidney tubules and cause acute kidney injury. The risk is higher with dehydration, rapid infusion, high doses, existing kidney disease and other nephrotoxic drugs. The nurse makes sure the client receives adequate fluids as prescribed, infuses each dose slowly over the time stated in the labeling and pharmacy instructions, and tracks urine output, BUN and creatinine so the provider can adjust the dose if kidney function changes. Option A is wrong because antacids have no role with an IV drug. Option B is wrong because acyclovir is never given by rapid IV push; fast infusion raises the risk of kidney injury. Option C is wrong because limiting fluids increases crystal formation.

Answer: C. "My urine may turn dark yellow or brown while I take this, and that is harmless."

Rationale: Nitrofurantoin can turn urine dark yellow or brown. This is harmless, and knowing about it ahead of time keeps clients from stopping the drug in alarm. Option A is wrong because the client finishes the prescribed course even when symptoms improve. Option B is wrong because nitrofurantoin is taken with food or milk, which improves absorption and reduces nausea. Option D is wrong because nitrofurantoin can cause lung reactions, sudden or slow to develop; a new cough, chest pain, fever or shortness of breath must be reported. The drug is also generally avoided when kidney function is significantly reduced, so the nurse checks recent kidney labs.

Answer: A. Today's ECG shows a QTc of 512 ms (438 ms a month ago), and the serum potassium is below the lab's reference range

Rationale: Macrolide antibiotics such as azithromycin can prolong the QT interval and, in rare cases, trigger torsades de pointes, a dangerous ventricular dysrhythmia. The risk is higher when the QT interval is already long, when potassium or magnesium is low, with a slow heart rate, and with other QT-prolonging drugs. A QTc that has lengthened this much along with low potassium should be reported before the first dose so the provider can correct the electrolytes and decide whether a different antibiotic is safer. Option B is expected with pneumonia. Option C does not need to be reported; collecting cultures before the first antibiotic dose is good practice. Option D is a minor past side effect, not an allergy or a contraindication.