Lecture 9: Antibiotics

sulfonamides - drug names

• sulfamethoxazole

• trimethoprim-sulfamethoxazole

sulfonamides - mech of action

inhibit folate synthesis (bacteriostatic)

sulfonamides - indications

• UTI

• resp infection

• MRSA

sulfonamides - side effects

• allergic rxn

• photosensitivity

• GI upset 

sulfonamides - special considerations

• high concentration in kidneys

• monitor for sulfa allergies 

penicillins - drug names

• penicillin G

• amoxicillin

• ampicillin

• piperacillin-tazobactam

penicillins - mech of action

inhibit cell wall synthesis (bactericidal)

penicillins - indications

• gram + infections

• some gram -

penicillins - side effects

• allergic rxn

• GI upset 

penicillins - special considerations

• monitor for penicillins allergy

• cross sensitivity with cephalosporins 

cephalosporins - drug names

• cephalexin

• cefazolin

• ceftriaxone

• cefepime

• ceftaroline 

cephalosporins - mech of action

inhibit cell wall synthesis (bactericidal)

cephalosporins - infications

• broad spectrum

• gram +

• gram -

• anaerobic

cephalosporins - side effects

• diarrhea

• rash

• pruritus

cephalosporins - special considerations

• cross-sensitivity with penicillins

• monitor renal function

macrolides - drug names

• erythromycin

• azithromycin

• clarithromycin 

macrolides - mech of action

inhibit protein synthesis (bacteriostatic/bactericidal)

macrolides - indications

• resp infections

• skin infection

• STIs

macrolides - side effects

• GI upset

• QT prolongation

macrolides - special considerations

• avoid use with CYP3A4 inhibitors

• monitor cardiac function

tetracyclines - drug names

• tetracycline

• doxycycline

• tigecycline 

tetracyclines - mech of action

inhibit protein synthesis (bacteriostatic)

tetracyclines - indications

• acne

• chlamydia

• pneumonia

• Rickettsia infections 

tetracyclines - side effects

• photosensitivity 

• tooth discoloration

tetracyclines - special considerations

• avoid children under 8 and pregnancy

• monitor for superinfections

fluoroquinolones - drug names

• ciprofloxacin

• levofloxacin

• moxifloxacin 

fluoroquinolones - mech of action

inhibit DNA replication (bactericidal) 

fluoroquinolones - indications

• UTI

• resp infections

• skin infections 

fluoroquinolones - side effects

• QT prolongation

• peripheral neuropathy 

fluoroquinolones - special considerations

• avoid in prepubescent children

• monitor for liver injury 

aminoglycosides - drug names

• gentamicin

• amikacin

• tobramycin 

aminoglycosides - mech of action

inhibit protein synthesis (bactericidal) 

aminoglycosides - indications

• serious gram - infections

• combinations therapy for gram + 

aminoglycosides - side effects

• nephrotoxicity 

• ototoxicity 

aminoglycosides - special considerations

• therapeutic drug monitoring

• caution neonates 

sulfonamides - nursing implications

• assess for sulfa allergies + monitor for delayed cutaneous rxn

• hydration

• monitor for signs of superinfection 

penicillins - nursing implications

• penicillin allergies and cross-sensitivity with penicillins

• monitor for allergic rxn

  • urticaria

  • pruritus

  • angioedema 

• pt education on potential drug interactions

  • oral contraceptives

  • NSAIDs

cephalosporins - nursing implications

• assess for allergies + cross sensitivity with penicillins

• monitor for common adverse effects

  • diarrhea

  • rash

  • pruritus  

• ensure proper admin timing/hydration

macrolides - nursing implications

• assess baseline cardiac function and hearing status

• monitor for GI related adverse effects 

  • especially with erythromycin

• pt education on proper dosage and admin instructions 

tetracyclines - nursing implications

• avoid use children <8 and pregnant women

  • risk for tooth discolouration and fetal skeletal development 

• monitor for photosensitivity and superinfection

• pt education on avoiding dairy products antacids close to dosing times 

aminoglycosides - nursing implications

• conduct therapeutic drug monitoring to avoid nephrotoxicity and ototoxicity

• adjust dosing based on renal function and creatinine clearance

• pt education to report changes in hearing, balance, renal function 

quinolones - nursing implications

• avoid use in prepubescent children

  • cartilage development concerns

• monitor for QT interval prolongation and peripheral neuropathy 

clindamycin - nursing implications

• assess for hypersensitivity and contraindications (ulcerative colitis)

• monitor for GI adverse effects and neuromuscular blocking properties

• pt education on proper oral/topical admin

metronidazole - nursing implications

• monitor for dizziness, headache, GI discomfort

• pt education on avoiding alcohol during therapy

• wat for drug interactions with lithium, benzodiazepines, warfarin 

nitrofurantoin - nursing implications

• monitor for GI upset, skin rxn, hepatotoxicity

• pt education to take plenty of fluids, food, milk

• signs of superinfection and peripheral neuropathy 

vancomycin - nursing implications

• therapeutic drug monitoring to avoid nephrotoxicity and ototoxicity

• monitor for red man syndrome and hypotension with rapid infusion

• pt education on proper admin and monitor IV site 

essential before antibiotic therapy

essential to obtain cultures from appropriate site before beginning antibiotic therapy

community-associated infections

occur in individuals not recently hospitalized

health care-associated infections

arise more than 48 hours post-admission

antibiotics classified as

• bacteriostatic = inhibiting growth

• bactericidal = directly killing bacteria 

empiric vs definitive therapy

• empiric

  • initiated when infections signs appear before ID causative organism

• definitive

  • treatment based on culture results 

broad-spectrum antibiotic therapy

target numerous organisms

narrow-sprectrum antibiotics

focus on few, overuse = antibiotic resistance

prophylactic antibiotic thereapy

prevent infections during high-risk procedures

four main mechs of antibiotic action

1. interference with bacterial cell wall synthesis

2. interference with protein synthesis

3. interference with replication of nucleic acids (DNA/RNA)

4. antimetabolite action disrupts metabolic rxn in bacterial cell

sulfonamides and their effects

• broad antibacterial activity in gram +-

• commonly used for UTis

• cause delayed allergic rxns (fever + skin rashes)

penicillin subgroups and effects

• four subgroups

• effective against gram +

• limited efficacy for gram -

• allergic rxns (urticaria/angioedema) + idiosyncratic steven johnson syndrome

cephalosporins and their generations

• semisynthetic antibiotics related to penicillin

• broad spectrum bacteria

• 5 generations

  • 1st gen target gram +

  • later gen for gram -

  • cefepime = 4th gen cephalosporin = UTI and pneumonia

  • ceftaroline = 5th gen = MRSA

• adverse effects

  • diarrhea, rash, potential cross-sensitivity in those allergic to penicillin

carbapenems and use

• broad-spectrum against gram +

• can cause seizures

macrolide antibiotics and use

• macrolides

  • azithromycin

  • clarithromycin

  • erythromycin 

• bacterial at high concentrations 

• fidaxomicin for c.diff 

• nausea/vomiting

tetracyclines use, effects, risks

• bacteriostatic antibiotics

• inhibit protein synthesis in bacteria

• tooth discoloration and serious SA in fetuses/children

• treat chlamydia/syphilis 

how antibiotic resistance happens

• lots of germs and some are drug resistant

• antibiotics kill bacteria causing illness as well as the good bacteria protecting body from infection

• drug resistant bacteria now able to grow and take over

• some bacteria give their drug resistance to other bacteria 

penicillin - what to know

• side effects

  • rash

  • itching

  • hives

  • anaphylaxis

• nursing implications

  • pt check label regarding admin with food

  • pt education to wear med-alert bracelet if allergic

  • monitor for 30 min when given parenterally

  • admin epinephrine if anaphylaxis occurs 

  • monitor for circulatory overload and bleeding tendencies for ticarcillin

cephalosporins - need to know 

• side effects

  • hypersensitivity rxn = rahs, pruritus, fever

  • nause, vomiting, diarrhea

  • severe immediate anaphylactic RARE

  • superinfection

• nursing implications

  • notify HCP if diarrhea - promote development of c.diff

  • monitor renal/hepatic studies throughout therapy

  • do not use with calcium diluents (ringers)

  • GI upset occur, take med with foood

  • pt education on refrigerating oral suspensions  

macrolides - need to know

• side effects

  • diarrhea

  • fatal cardiac dysrhythmias 

• nursing implications

  • take 1-2 hrs before food/antacids

  • observe for development of suprainfection

  • take for entire course of therapy even if S/S disappear

  • IV infused over 60 min

  • erythromycin = monitor warfarin levels and watch for prolonged QT waves 

tetracyclines - need to know

• precautions

  • not children under 8 or pregnant

  • teeth staining

• side effects

  • altercation of vaginal and intestinal flora resulting from diarrhea and GI upset

  • photosensitivity, suprainfection (c.diff) 

• nursing implications

  • take on empty stomach

  • wait 2hrs to consume antacids, milk products, Fe supplements

  • monitor for diarrhea = indication of superinfection of bowel (c.diff) 

  • wear sunscreen and protective clothing