antibiotics

What pathogen factors determine antibiotic selection?

Identify the specific organism and determine its susceptibility to antibiotics.

What does culture and sensitivity testing tell you?

Culture identifies the organism; sensitivity testing determines which antibiotics inhibit it and which it resists.

What is the difference between antibiotic sensitivity and resistance?

A sensitive organism responds to the antibiotic; a resistant organism is not effectively inhibited by it.

Which host factors affect antibiotic therapy?

Immune function, conditions at the infection site, allergies, age, pregnancy, and genetics.

Why do age and kidney function matter when selecting an antibiotic?

Very young and older patients may handle drugs differently; impaired kidney function affects elimination of renally excreted antibiotics.

What is the difference between bacteriostatic and bactericidal drugs?

Bacteriostatic drugs suppress bacterial growth; bactericidal drugs kill bacteria.

How can beta-lactamase contribute to antibiotic resistance?

A beta-lactamase-producing organism can defeat a susceptible beta-lactam antibiotic; the materials note that penicillins vary in beta-lactamase sensitivity.

Which actions help prevent antibiotic resistance in the uploaded materials?

Treat bacterial infection rather than contamination, complete the prescribed course, and eliminate invasive catheters when appropriate.

When is antibiotic prophylaxis indicated in the uploaded materials?

Selected cardiac, vascular, orthopedic, or GI surgeries; bacterial endocarditis prevention; and neutropenia.

What is a superinfection?

A new infection that develops during treatment of the original infection.

Why can prolonged or broad-spectrum antibiotic therapy cause a superinfection?

It disrupts normal flora, allowing organisms such as C. difficile or Candida to overgrow.

Which antimicrobial drugs inhibit bacterial cell wall synthesis?

Penicillins, cephalosporins, carbapenems, isoniazid, and vancomycin are listed in the materials.

Which antimicrobial classes inhibit protein synthesis?

Aminoglycosides, tetracyclines, ketolides, macrolides, and streptogramins.

Which antimicrobial drugs target RNA synthesis, DNA synthesis, and folic acid production?

Rifampin targets RNA synthesis; fluoroquinolones target DNA synthesis; sulfonamides inhibit folic acid production.

Which penicillins are listed in the materials?

Penicillin V, piperacillin, amoxicillin, and ampicillin.

How do penicillins work, and are they bactericidal or bacteriostatic?

They disrupt bacterial cell wall synthesis, causing cells to expand and burst; they are bactericidal.

Why should kidney function be monitored during penicillin therapy?

Penicillins are eliminated by the kidneys.

What allergy assessment is emphasized before administering penicillin?

Assess for penicillin and cephalosporin allergies because the materials identify cross-allergy concerns.

What common effects and possible allergy findings are listed for penicillins?

Nausea, vomiting, and diarrhea; possible allergy findings include rash, itching, and fever.

What blood cell changes can occur with penicillins?

Decreased red blood cells, white blood cells, and platelets.

What penicillin interactions are highlighted in the course materials?

Aminoglycosides: possible antagonism; oral contraceptives: decreased effectiveness is listed.

What should a patient taking penicillin or amoxicillin be taught?

Complete the prescribed course, recognize allergy symptoms, and take the medication with water.

Which cephalosporins are listed in the materials?

Cephalexin, cefoxitin, cefotaxime, and cefepime.

How do cephalosporins work?

They bind to penicillin-binding proteins and disrupt bacterial cell wall synthesis; they are bactericidal.

What major effectiveness problem is identified for cephalosporins?

Bacterial resistance.

Why is kidney function important during cephalosporin therapy?

Most cephalosporins are excreted by the kidneys.

What are the most common cephalosporin adverse reactions?

Rash and diarrhea.

What increases the risk of superinfection during cephalosporin therapy?

Large doses or prolonged treatment.

What allergy concern should be assessed before giving a cephalosporin?

A history of penicillin allergy because the materials identify possible cross-reactivity.

Which cephalosporin interaction increases kidney injury risk?

Concurrent cefazolin and nephrotoxic drugs.

What nursing care and teaching are emphasized for cephalosporins?

Assess allergies and alcohol use, monitor for antibiotic-associated colitis, take with food if GI upset occurs, and use alternate birth control as instructed in the materials.

A patient receiving a cephalosporin develops severe diarrhea. What complication should the nurse consider?

Antibiotic-associated pseudomembranous colitis caused by C. difficile; assess and report the finding.

Which drugs are tetracyclines, and what infections are they used for?

Tetracycline and minocycline; uses include acne, periodontal disease, and Lyme disease.

How do tetracyclines work?

They bind to the bacterial 30S ribosomal subunit and inhibit protein synthesis; they are bacteriostatic.

Why are tetracyclines avoided during the second half of pregnancy and in children 8 years or younger?

They can affect fetal bone and tooth development and permanently discolor developing teeth.

What organ impairments are listed as contraindications to tetracyclines?

Severe renal or hepatic impairment.

Which substances interact with tetracyclines?

Milk products, vitamin D, iron supplements, magnesium-containing laxatives, and antacids.

How should oral tetracycline be administered according to the materials?

Give with a full glass of water; separate antacids by 1–3 hours.

What milk-timing instruction appears in the tetracycline study guide?

Drink milk 1 hour before or 2 hours after the medication.

What adverse effects should be monitored during tetracycline therapy?

Nausea, vomiting, diarrhea, C. difficile or vaginal yeast superinfection, photosensitivity, dizziness, lightheadedness, and permanent tooth damage.

What assessments and teaching are emphasized for tetracyclines?

Assess pregnancy status, age, and renal or hepatic impairment; monitor urine output and teach protection from sunlight.

A patient taking tetracycline develops significant diarrhea. Why is this concerning?

Broad-spectrum therapy can lead to a potentially life-threatening C. difficile bowel superinfection.

Which aminoglycosides are listed, and what is their primary use?

Tobramycin, neomycin, and gentamicin; they treat serious gram-negative bacterial infections.

How do aminoglycosides act according to the lecture slides?

They inhibit bacterial protein synthesis and have bactericidal activity.

Why are aminoglycoside serum levels monitored?

The same dose can produce different levels in different patients, and excessive exposure increases toxicity risk.

What is the difference between an aminoglycoside peak and trough level?

Peak measures the high post-dose concentration; trough measures the concentration remaining just before the next dose.

When are aminoglycoside peak and trough levels collected in the lecture slides?

Peak: 30 minutes after an IM injection or infusion; trough: just before the next dose.

What aminoglycoside peak-level withholding guidance appears in the slides?

Withhold the drug if the peak exceeds the listed 5–10 mcg/mL range; the materials do not provide separate targets for each drug.

What are the major aminoglycoside toxicities?

Ototoxicity, nephrotoxicity, and neurotoxicity; blood dyscrasias can also occur.

Which early findings suggest aminoglycoside ototoxicity?

Tinnitus, vertigo, persistent headache, hearing loss, or impaired balance.

Which additional findings suggest aminoglycoside neurotoxicity?

Paresthesias, muscle twitching, and seizures.

How do aminoglycosides injure the kidneys?

They damage cells of the proximal renal tubules.

What aminoglycoside assessments and labs are emphasized?

Hearing assessment or whisper test, urine output, renal findings, serum drug levels, and periodic CBC.

A patient receiving gentamicin develops hearing loss or low urine output. What action is emphasized in the study guide?

Stop or withhold the medication and report the finding because it suggests ototoxicity or nephrotoxicity.

Which drugs increase aminoglycoside ototoxicity risk?

Furosemide and aspirin; avoid concurrent neurotoxic drugs.

Which drugs increase aminoglycoside nephrotoxicity risk?

NSAIDs, aspirin, and vancomycin.

How should an IM aminoglycoside be administered, and what solution should be discarded?

Inject deeply into a large muscle; discard discolored solutions or solutions containing particles.

Which sulfonamides are listed, and how do they work?

Sulfamethoxazole–trimethoprim and sulfisoxazole; they suppress bacterial growth by inhibiting folic acid needed for DNA synthesis.

What uses are listed for sulfonamides?

UTIs; the study guide also lists burns.

What adverse effects are emphasized for sulfonamides?

Nausea, vomiting, diarrhea, crystalluria, blood dyscrasias, and Stevens–Johnson syndrome.

What is crystalluria, and what teaching helps reduce this concern during sulfonamide therapy?

Crystals form in urine and may contribute to stones; take the medication with a full glass of water.

What skin findings during sulfamethoxazole–trimethoprim therapy require immediate reporting?

A severe red or purplish rash, especially with blistering, because it may indicate Stevens–Johnson syndrome.

Why is Stevens–Johnson syndrome a priority concern?

It is a medical emergency involving severe skin injury.

What allergy history should be reviewed before sulfonamide therapy?

Sulfonamide allergies and reactions to chemically related drugs listed in the materials: NSAIDs, sulfonylureas, thiazides, and loop diuretics.

Which findings suggest hemolysis during sulfonamide therapy, and what lab may be monitored?

Fever, pallor, or jaundice; periodic blood counts may be ordered.

How should sulfonamides be administered according to the materials?

On an empty stomach with a full glass of water.

Why are sulfonamides avoided near term in pregnancy and in infants younger than 2 months?

Risk of kernicterus; they may also worsen maternal folate deficiency.

Which fluoroquinolones are listed in the materials?

Ciprofloxacin, levofloxacin, ofloxacin, and moxifloxacin.

How do fluoroquinolones work, and what infections are listed as uses?

They inhibit bacterial DNA gyrase and replication; uses include respiratory, urinary tract, joint, and soft tissue infections.

What boxed warning is emphasized for fluoroquinolones?

Tendinitis and tendon rupture, commonly involving the Achilles tendon.

Which patients have especially high tendon rupture risk with fluoroquinolones?

Patients older than 60, corticosteroid users, and kidney, heart, or lung transplant recipients.

What age precaution is listed for fluoroquinolones?

The materials advise avoiding them in patients younger than 18.

What findings should the nurse assess for during ciprofloxacin or levofloxacin therapy?

Leg or heel pain, difficulty walking, and photosensitivity.

A patient taking ciprofloxacin reports new heel pain and difficulty walking. What is the priority concern?

Possible tendinitis or tendon rupture; promptly report the findings.

Which substances reduce fluoroquinolone absorption?

Aluminum or magnesium antacids, iron salts, zinc salts, and sucralfate.

How should fluoroquinolones be timed with antacids and ferrous sulfate in the materials?

Administer the fluoroquinolone at least 4 hours before them.

What other adverse effects can occur with fluoroquinolones?

Dizziness, headache, restlessness, confusion, nausea, vomiting, diarrhea, abdominal pain, photosensitivity, and Candida infection of the throat.

What patient teaching is emphasized for fluoroquinolones?

Avoid direct sunlight, use protective clothing, sunglasses, and sunscreen, and avoid strenuous activity for 5–10 days after completing therapy.

What uses are listed for metronidazole?

Protozoal STIs such as trichomoniasis and H. pylori infection associated with peptic ulcer disease.

What adverse effects are listed for metronidazole?

Peripheral neuropathy, optic neuropathy, seizures, dysuria, nausea, epigastric distress, and headache.

What metronidazole absorption interactions are listed in the materials?

H2 blockers, PPIs, and antacids are listed as decreasing absorption.

What teaching is emphasized for metronidazole?

Take with food, increase fluids, avoid alcohol because of a disulfiram-like reaction, and arrange partner notification and treatment when used for an STI.

What infection is vancomycin reserved for in the materials?

Serious MRSA infection.

What major adverse effects are emphasized for vancomycin?

Ototoxicity and a histamine-mediated infusion reaction called red man syndrome in the materials.

How should IV vancomycin be administered according to the materials?

Infuse over at least 1 hour to reduce infusion-related reactions.

What nursing assessments and interventions are emphasized for vancomycin?

Assess hearing, monitor for hypersensitivity or urticarial rash, and administer prescribed pretreatment diphenhydramine.

Why is concurrent vancomycin and an aminoglycoside concerning?

Increased ototoxicity risk; vancomycin is also listed as increasing aminoglycoside nephrotoxicity risk.

What are fungi, and how can humans be exposed?

Single-celled or multicellular organisms, including yeasts, molds, and mushrooms; exposure can occur through contaminated soil or inhaled spores.

What conditions encourage fungal overgrowth in the study guide?

Warm, dark, moist environments; fungi may become problematic when normal flora overgrow.

How do superficial and systemic fungal infections differ?

Superficial infections affect scalp, skin, nails, and mucous membranes; systemic infections affect internal organs such as lungs, brain, and digestive organs.

How does treatment differ for superficial and systemic fungal infections?

Superficial infections usually use topical agents, with oral therapy for deeper infections; systemic infections require oral or parenteral therapy.

Why is immunosuppression important in fungal infections?

Suppressed immune defenses increase the risk of serious systemic fungal infections, which can be fatal; HIV is an example.

What distinction do the materials make between community-acquired and opportunistic fungal infections?

Community-acquired infections can affect people with intact immunity; opportunistic infections are described as occurring in immunosuppressed patients, often in health care settings.

Which azoles are taught, and how do they work?

Fluconazole and ketoconazole inhibit ergosterol synthesis, disrupting the fungal cytoplasmic membrane.

What serious azole adverse effects are emphasized in the materials?

Cardiac suppression through a negative inotropic effect and liver injury that may progress to liver failure.

Why does a history of heart problems matter before azole therapy in these materials?

The listed negative inotropic effect can further weaken cardiac pumping.

Which findings suggest hepatotoxicity during azole therapy?

Anorexia, nausea, vomiting, jaundice, dark urine, and clay-colored stools; the study guide also lists ascites.

What hormonal effects should be monitored during prolonged azole therapy?

In males: gynecomastia, decreased libido, and erectile dysfunction; in females: irregular menses.

What should patients understand about the duration of antifungal therapy?

Prolonged treatment may be necessary, sometimes for 3–6 months.

How does nystatin work, and what infections does it treat?

It binds to fungal membrane sterols, allowing intracellular contents to leak; it treats Candida infections of the mouth, skin, vagina, and intestines.