Antibiotic Slide Deck Flashcards
What are common causes of drug resistance?
- Overuse of broad-spectrum abx. - Over prescription of abx. for viral illnesses - Use of abx in animals that enter the food chain
Which type of bacteria has a cytoplasmic membrane surrounded by a touch rigid mesh cell wall?
Gram + organisms - Ex: staph aureus, strep pneumoniae, clostridium - stain purple
Which type of bacteria has a thin cell wall surrounded by a second lipid membrane?
Gram - organisms - Ex: E. coli, pseudomonas, H. pylori, Neisseria, gonerrhea, salmonella - stain pink
What type of organism needs oxygen to survive?
Obligate aerobes
What type of organism is poisoned by oxygen?
Obligate anaerobes
What type of organism can grow with or without oxygen because they can metabolize energy aerobically or anaerobically?
Facilitative anaerobes
What type of antibiotic stops the bacteria from growing but does not kill it?
Bacteriostatic
What type of antibiotic kills the bacteria?
Bactericidal - important to use this type in patients that are immunocompromised
Important factors to keep in mind when prescribing antibiotics:
- immune system function - renal and hepatic function - Age - Pregnancy/lactation - Risk for multi-drug-resistance organisms - Patient adherence: lowest frequency for the shortest duration - cost effective - for kids: taste good and most concentrated dose
What is the MOA of the penicillins?
Inhibit the biosynthesis of peptidoglycan bacterial cell wall
Penicillin V and Penicillin G Benzathine are active against what type of organisms?
Narrow spectrum - gram + mostly: S. pneumoniae, GABHS - bactericidal Pen V (oral) is best for group A beta-hemolytic strep - strep throat/pharyngitis Pen G (IV) best for syphilis infection (T. pallidum)
Amoxicillin and Augmentin (Amox/Clavulanic Acid) are active against what type of organisms?
More broad spectrum - Same gram + organisms as Pen V/Pen G but also some activity against gram - organisms - bactericidal Amoxicillin - 1st line for AOM and sinusitis Augmentin - 1st line fx for bites, UTI in pregnancy
PCNs Adverse Drug Reactions (ADR)
- serious allergic hx - Rash - GI (N/V/D) - Fungal overgrowth/candidiasis
Cephalosporin MOA
inhibit mucopeptide synthesis in the bacterial cell wall Bactericidal
Name common gram + organisms and where the common infections they cause
•Staphylococcus aureus -Commonly causes skin infections
–Can also cause endocarditis, sepsis, osteomyelitis, pneumonia
•Streptococcus
–Pyogenes (pharyngitis [GAS], impetigo, cellulitis)
–Pneumoniae (pneumonia, meningitis, sepsis)
–Agalactiae: meningitis, vaginitis [GBS], UTI, endocarditis, skin infection
•Enterococcus
–Anaerobic
–Can cause UTI, prostatitis, intra-abdominal infections, cellulitis, endocarditis
•Bacilli
–Lactobacilli -present in the mouth, vagina
–C. difficile
Name common gram negative organisms and the infectiosn they cause
•Escherichia coli
–Found in the intestines of humans and animals
–Responsible for food-borne illness and UTI
–Can also cause cholecystitis, traveler’s diarrhea and sepsis
•Pseudomonas aeruginosa
–Most common in hospitalized patients
–Can cause otitis externa, Pneumonia, wound infection, UTI, sepsis
•Klebsiella pneumoniae
–Colonizes the human mouth and gut
–Commonly causes Pnuemonia, UTI, sepsis
- Neisseria gonorrhoeae
- Haemophilus influenzae
–Pneumonia bronchitis, otitis media, cellulitis, infectious arthritis
How does spectrum of activity differ between classes of cephalosporins?
Earlier generations have good gram + coverage and less gram - coverage
Later generations have better gram - coverage and less gram + coverage
Cephalosporins ADRs
C. diff, hypersensitivity rx, hemolytic anemia, neutropenia, leukopenia, coagulation abnormalities
Cephalosporins cautions/CIs
- hx of PCN allergy with anaphylaxis or hypersensitivity rx - safe in pregnancy/lactation and pediatrics
The stronger the drug (5th generation is strongest; 1st generation is weakest) - the more chance of a C. Diff infection
What drug is in the glycopeptide class?
Vancomycin (PO)
Vancomycin MOA and indication
- inhibits cell wall synthesis by binding to the D-A1a-D-A1a protein in the cell wall - oral is not well absorbed - stays in the GI tract - used for C. diff. infection
Vancomycin (oral) ADRs
- ototoxicity - nephrotoxicity ** monitoring for hearing and renal function
Lincosamides active against/MOA
Clindamycin - Gram + organisms - bacteriostatic - MRSA skin infections, dental infections, acne (topical) - inhibits protein synthesis by binding to the 50S subunit of bacterial ribosome
High risk for C. Diff
Clindamycin pt education
- take w/ full glass of water - sit or stand for 30 minutes after dose - call clinic if diarrhea occurs
Macrolides MOA/indications
Azithromycin, Erythromycin, Clarithromycin - Gram + and gram - organisms - bacteriostatic - inhibits RNA-dependent protein synthesis by binding to the 50S subunit **Think respiratory for this class** 1st line CAP 1st line pertussis 1st line chlamydia
Macrolides ADRs
- potent CYP450 inhibitor - combination with statins may increase risk of myopathy - skin rash 9urticaria, bullous eruptions, eczema, SJS) - GI distress (esp. E-mycin)
Tetracyclines MOA/indications
Tetracycline/Doxycycline - inhibit protein synthesis by reversibly binding to the 30S subunit of the bacterial ribosome - Doxy 1st line for RMSF and Lyme dz - CAP (2nd line)
Tetracyclines cautions/CI/ADRs
- Preg Cat D - avoid in children < 8 years old d/t teeth discoloring ADRs: - nephrotoxic - photosensitivity - hepatotoxicity
Tetracyclines patient teaching
Take with a full glass of water - do not take with milk or milk products (binds to calcium)
Can cause stomach upset/esophagitis
Fluoroquinolones MOA
Ciprofloxacin, Levofloxacin - interferes with bacterial enzymes required for the synthesis of bacterial DNA - breakage of DNA strands
Fluoroquinolones indications
Complicated infections - pyelonephritis (1st line) - complicated UTIs - CAP (3rd line)
Fluoroquinolones cautions/CIs
- BBW: risk of tendon rupture and tendonitis - risk of QT prolongation - no for children < 18 (unless pyelonephritis, anthrax, allergies to other meds) - not for use in pregnancy and lactation - high risk of superinfection - increasing resistance - not to be used for minor uncomplicated infections
Sulfonamides/Trimethoprim MOA
Sulfonamides block folic acid synthesis Trimethoprim inhibits DNA synthesis
Sulfamethoxazole and Trimethoprim (Bactrim) Indications
- UTI
- Community acquired MRSA
- excellent gram negative coverage and coverage of stap/strep (gram +)
Sulfonamides and Trimethoprim cautions/CIs
•Common hypersensitivity reactions: rash, fever, Stevens-Johnson syndrome (more common in HIV + patients)
- Not for use in pregnancy (anti-folate effects)
- Avoid in pediatrics < 2 months old
- Hyperkalemia (reduces K+ excretion)
- Avoid concomitant administration with K+ sparing drugs (triamterene, ACE, ARB)
Nitrofurantoin MOA/Indications
- Multifactorial MOA
- Bacteriostatic in low concentrations, Bactericidal in higher concentrations
May inhibit acetyl coenzymes - interferes with bacterial protein synthesis, cell wall synthesis, and aerobic energy metabolism Indications:
Indication: uncomplicated UTI (1st line), not indicated in complicated infections/pyelo
Nitrofurantoin ADRs
neuropathy, pulmonary reactions
Metronidazole MOA/Indiations
Flagyl - interacts with DNA structure causing strand breakage, inhibition of protein synthesis, and cell death - broad spectrum (bacterial and parasitic)
Indications: C. diff, bacterial vaginosis, stool infections, trichomoniasis (think below the belt infections) - anaerobic, protozoans, fungals
Metronidazole ADRs
- metallic tast - dark urine - hepatotoxicity - superinfections (rare)
Metronidazole cautions/CIs/pt education
- do not use in the 1st trimester of pregnancy - take with food - avoid alcohol during and for 2 days after tx (can cause disulfiram rx: N/V, H/A, flushing, dizziness, chest and abdominal discomfort) - BBW: potentially carcinogenic
Tinidazole MOA/indications
- thought to cause cytotoxicity by damaging DNA and preventing DNA synthesis - newer, more expensive Indications: bacterial vaginosis, trichomoniasis - more for fungal, protozoan, parasitic infections - not as much bacterial
Tinidazole cautions/CIs
- avoid in pregnancy - BBW: potentially carcinogenic
Impetigo treatment
Mupirocin (Bactroban) topically 3x/day for 5-14 days for up to 5 lesions Cephalexin (oral) if there are 5 or more impetigo lesions
Oral medication options for skin lesions
- give if moderate to severe impetigo (5 or more lesions), boils, perianal strep, cellulitis cephalexin, bactrim (amox/clavulanate), dicloxacillin If MRSA skin infection is suspected: CBD (cephalexin, bactrim, doxycycline)
Oral candidiasis treatment
- nystatin or clotrimazole loxenges
Topical antifungal agents
- used to treat vulvovaginal yeast infections - topical miconazole and clotrimazole - Fluconazole oral (systemic) x 1 dose
Topical treatment of tinea pedis (athlete’s foot) or tinea corporis (ringworm)
- thin layer of terbinafine, miconazole, ketoconazole, clotrimazole - use BID - wash hands well before and after use
Topical herpes simplex treatment
- topical acyclovir (zovirax) , penciclovir (denavir, and OTC docosanol (Abreva) - start as soon as possible
Fluconazole MOA/indications
- interferes with fungal CYP 450 activity - inhibits cell membrane formation - broad spectrum Indications: candidiasis (vaginal, oropharyngeal, esophageal)
Fluconazole cautions/CIs
- hard on liver - monitor hepatic function - QT prolongation - check EKG - avoid in pregnancy - CYP 3A4 and 2C9 inhibitor
Itraconazole MOA/indications
- interferes with fungal CYPE 450 activity - inhibits cell membrane formation - broad spectrum systemic treatment Indications: onychomycosis (fungal infection of nail bed)
Itraconazole cautions/CIs
- hard on liver - QT prolongation - avoid in pregnancy - BBW: avoid in patients with HF/myocardial dysfunction
Terbinafine/Ciclopirox (topical) MOA/indications
- synthetic allylamine derivative - inhibits squalene eposidase enzyme, a key enzyme in sterol biosynthesis in fungi - results in fungal cell death - metabolized by CYP450 Indication: onychomycosis (1st line) - off label: extensive tinea fungal infection
Terbinafine cautions/CIs
- arrhythmias (think QT) - hepatic impairment - avoid in pregnancy
Terbinafine ADRs
hepatotoxicity hepatic failure blood dyscrasias
