NUSC 2P19 Class 5 Rough

Why is cilastatin combined with imipenem in the formulation Primaxin?

Cilastatin inhibits a renal enzyme that breaks down imipenem, preserving its active drug levels.

Why must macrolide administration be carefully evaluated regarding concomitant medications?

Macrolides are highly protein-bound and can displace other protein-bound drugs, causing severe toxicity.

Which penicillin allergy presentation strictly contraindicates the use of cephalosporins?

A history of throat swelling or hives (anaphylactic reactions) from penicillin.

Why is ceftriaxone effective for treating central nervous system infections?

It easily crosses the meninges and diffuses directly into cerebrospinal fluid (CSF).

What severe integumentary adverse effects can occur with sulfonamides?

Photosensitivity, exfoliative dermatitis, Stevens-Johnson syndrome, and epidermal necrolysis.

What clinical signs characterize Red Man Syndrome?

Flushing or itching of the head, neck, face, and upper trunk.

What is definitive antibiotic therapy?

Antibiotic therapy specifically tailored to treat an organism identified through cultures.

In aminoglycoside monitoring, what does a trough level measure and why is it drawn?

It measures the lowest drug concentration to ensure adequate renal clearance and prevent organ toxicity.

What risk is associated with rapid infusion of carbapenems?

Drug-induced seizure activity (risk reduced by infusing over 60 minutes and adjusting dosage).

How does antibacterial spectrum change across the generations of cephalosporins?

Gram-positive coverage is highest in 1st generation and generally decreases through 3rd, while gram-negative coverage progressively increases and broadens.

Why are fluoroquinolones generally avoided in pediatric patients under 18 years of age?

Due to the increased risk of adverse musculoskeletal effects.

What route of elimination distinguishes ceftriaxone from most other $\beta$-lactams?

Elimination is primarily hepatic.

How do disinfectants differ from antiseptics in terms of application site and action?

Disinfectants kill organisms on nonliving objects (cidal), while antiseptics inhibit growth on living tissue (static).

Why do azithromycin and clarithromycin offer clinical advantages over erythromycin?

They cause fewer GI adverse effects, have a longer duration of action, better tissue penetration, and superior efficacy.

What clinical indicators signify a therapeutic response to antibiotic therapy?

Decrease in infection signs/symptoms, such as reduction of fever, normalization of WBC count, and disappearance of redness, pain, or drainage.

What is a subtherapeutic antibiotic response?

A scenario where the signs and symptoms of infection fail to improve despite antibiotic administration.

How far apart should oral quinolones and antacids or iron supplements be administered?

Patients must take interacting cations at least 1 hour before or after taking quinolones.

Which antibiotic classes target bacterial cell wall synthesis?

$\beta$-lactams, Vancomycin, Isoniazid, Ethambutol, Bacitracin, and Polymyxin.

What is the mechanism of action of macrolides?

They prevent protein synthesis within bacterial cells by binding to the 50S ribosomal subunit (bacteriostatic).

What impact does oral erythromycin have on GI motility?

It stimulates smooth muscle motility in the GI tract, causing nausea, vomiting, abdominal cramps, and diarrhea.

What is the primary route of administration for quinupristin-dalfopristin (Synercid)?

Intravenous injection only.

Which new class of antibiotics does linezolid belong to, and what drug-food interactions exist?

Oxazolidinones; it interacts with SSRIs (causing serotonin syndrome) and tyramine-containing foods.

Why should oral penicillins be taken with water rather than acidic juices?

Acidic fluids can nullify the drug's antibacterial action.

What defines a community-acquired infection?

An infection acquired by a person who has not been hospitalized or undergone a medical procedure within the past year.

What mechanism explains the bactericidal effect of quinolones?

They alter bacterial DNA by inhibiting essential replication enzymes, causing cell death.

How does colistimethate sodium exert its antimicrobial effect?

It penetrates and disrupts the cell membrane of susceptible gram-negative bacterial strains.

What is prophylactic antibiotic therapy?

Antibiotic treatment administered to prevent an infection, such as before surgery or following trauma.

What is the single most important method for preventing health care–associated infections?

Handwashing

Why is nitrofurantoin specifically effective for urinary tract infections?

It concentrates directly in the urine.

Which antibiotic classes inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit?

Chloramphenicol, Macrolides, Clindamycin, and Streptogramins.

Why do sulfonamides spare human cells while harming susceptible bacteria?

Human cells use preformed folic acid from the diet, whereas target bacteria must synthesize their own folic acid.

Why are aminoglycosides rarely administered orally?

They have extremely poor oral absorption.

Why is it important to ensure patients complete the full course of prescribed antibiotics?

To eradicate the infection completely and prevent the development of bacterial drug resistance.

Which antibiotic classes target bacterial DNA replication?

Quinolones and Metronidazole.

Which antibiotics are reserved for Klebsiella pneumoniae carbapenemase (KPC) producing organisms?

Tigecycline and colistimethate sodium.

When is oral vancomycin prescribed instead of intravenous vancomycin?

Oral vancomycin is used specifically for localized GI tract infections like C. difficile colitis and staphylococcal enterocolitis.

What diagnostic step should ideally be taken before initiating antibiotic therapy?

Culturing the suspected areas of infection to identify the causative organism and drug susceptibilities.

Which genetic enzymatic deficiency increases susceptibility to drug-induced hemolytic anemia from certain antibiotics?

Glucose-6-phosphate dehydrogenase (G6PD) deficiency.

What toxicities must be monitored when a patient is receiving vancomycin?

Ototoxicity and nephrotoxicity.

Why are oral cephalosporins routinely administered with food?

To decrease gastrointestinal upset, even though food slightly delays drug absorption.

Which 1st-generation cephalosporins are used for surgical prophylaxis and staphylococcal infections?

Cefazolin (IV/IM) and Cephalexin (oral).

What adverse effect can occur when cephalosporins are taken with alcohol?

A disulfiram-like acute alcohol intolerance reaction.

Which two major antibiotic classes are most frequently associated with severe allergic anaphylactic reactions?

Penicillins and Sulfonamides.

What ratio of quinupristin to dalfopristin makes up the synergistic agent Synercid?

A 30:70 combination.

Why should patients taking oral contraceptives use back-up contraception while on penicillin or tetracycline therapy?

Antibiotics can decrease gastrointestinal gut flora required to recirculate and maintain oral contraceptive efficacy.

Which antibiotic classes inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit?

Aminoglycosides and Tetracyclines.

Why is SMX-TMP commonly prescribed for outpatient Staphylococcus infections?

Because of the high prevalence of community-acquired MRSA infections.

How do structural differences distinguish gram-positive from gram-negative bacteria?

Gram-positive organisms have a thick cell wall and outer capsule, whereas gram-negative organisms have a more complex cell structure that makes them harder to treat.

What key clinical signs alert the nurse to an impending antibiotic superinfection?

Fever, perineal itching, new cough, lethargy, or unusual vaginal/mucosal discharge.

What treatment limitation exists for Extended-Spectrum $\beta$-Lactamase (ESBL) producing organisms?

They are resistant to all $\beta$-lactam antibiotics and aztreonam, and can generally only be treated with carbapenems or quinolones.

What two major organ toxicities are associated with aminoglycoside therapy?

Nephrotoxicity (kidney damage) and Ototoxicity (auditory and vestibular impairment).

What is empiric antibiotic therapy?

Treatment of an infection initiated before specific culture and sensitivity results have been reported.

What mechanism explains the antibacterial action of sulfonamides?

They inhibit the bacterial synthesis of folic acid required for purine and nucleic acid synthesis.

Which antibiotic classes act as bacterial antimetabolites?

Sulfonamides, Dapsone, and Trimethoprim.

What criterion defines a health care–associated infection regarding the timing of onset?

It occurs more than 48 hours after admission to a health care facility.

What severe gastrointestinal condition is strongly associated with clindamycin administration?

Pseudomembranous colitis (Clostridium difficile infection).

How long should a nurse monitor a patient for an allergic reaction after administering penicillin?

At least 30 minutes.

Which 3rd-generation cephalosporin is specifically utilized for difficult-to-treat infections caused by Pseudomonas species?

Ceftazidime

Which fixed-dose combination antibiotic is commonly used to treat Pneumocystis jiroveci pneumonia?

Sulfamethoxazole-trimethoprim (SMX-TMP).

What key patient teaching point regarding sunlight applies to tetracyclines?

Avoid sunlight exposure and tanning beds due to drug-induced photosensitivity.

What causes Red Man Syndrome during vancomycin therapy, and how is it prevented?

It is caused by rapid IV infusion triggering histamine release; it is prevented by infusing vancomycin slowly over at least 60 minutes.

Why are trade names of penicillin combinations a frequent source of medication errors?

Many combination trade names (e.g., Clavulin) do not end in 'cillin', masking their penicillin content to clinicians.

By what mechanism do cations like calcium, magnesium, and aluminum impair tetracycline absorption?

They chelate (bind) with tetracyclines to form insoluble complexes in the gastrointestinal tract.

What effect do NSAIDs have when co-administered with penicillins?

NSAIDs compete for protein binding, potentially increasing free active penicillin concentrations.

What is the bactericidal mechanism of action of penicillins?

They bind to penicillin-binding proteins inside bacterial cells, disrupting normal cell wall synthesis and causing cell lysis.

What defines a superinfection during antibiotic treatment?

A secondary infection occurring when normal body flora are destroyed by antibiotics, allowing opportunistic pathogens (e.g., Clostridium difficile) to overgrow.

Why are tetracyclines contraindicated in children under 8 years old and pregnant women?

They bind to calcium in developing teeth causing permanent discoloration, and may stunt fetal skeletal growth.

For what type of microbial infections is metronidazole primarily indicated?

Anaerobic bacterial infections and protozoal infections.

What four antibiotic sub-classes constitute the $\beta$-lactam group?

Penicillins, Cephalosporins, Carbapenems, and Monobactams.

What general fluid instruction applies to all oral antibiotic administration?

Take with at least 180 mL of water to optimize absorption.

What specific indication is unique to the macrolide fidaxomicin?

Treatment of Clostridium difficile–associated diarrhea.

What severe musculoskeletal black-box warning is issued by Health Canada for fluoroquinolones?

An increased risk of tendonitis and tendon rupture.

Which 2nd-generation cephalosporin provides coverage against anaerobic bacteria and is used for colorectal surgical prophylaxis?

Cefoxitin

Which antibiotic generation does cefepime hydrochloride belong to?

4th generation cephalosporins.

What fluid intake instruction should be given to patients taking sulfonamides?

Drink 2000 to 3000 mL of fluid per 24 hours to prevent crystalluria.