Flashcards in Antibiotic Therapy Deck (84)
0
Vancomycin is a "BLANK"
Glycopeptide
1
Mechanism of action of glycopeptides
Inhibition of bacterial cell wall synthesis. Work at an earlier stage than do beta-lactams.
2
Daptomycin is a "BLANK"
Lipopeptide
3
Mechanism of action of Lipopeptides
Disruption of cell wall.
- Calcium dependent
- Depolarizes cell membrane
- Disrupts RNA, DNA, protein synthesis --> cell death
4
In general, Glycopeptides/Lipopeptides are active against:
Gram +ve organisms, including beta-lactam resistant organisms (i.e. MRSA)
5
Are Glycopeptides/Lipopeptides bacteriostatic or bactericidal?
Bactericidal
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This Glycopeptide is slowly cidal, and when given PO is not systemically absorbed
Vancomycin
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Lung surfactant inactivates "BLANK"; therefore, this agent should not be used to treat pneumonia!
Daptomycin
8
Spectrum and indications for Vancomycin IV
Spectrum: Gram +ve (Enterococci, penicillin resistant Streptococci, MRSA, CNS
Indications: Bacteremia, pneumonia, endocarditis, bone/joint, SSTI, surgical prophylaxis
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Spectrum and indications for Vancomycin PO
Spectrum: C. difficile
Indications: C. difficile infection
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Spectrum and indications for Daptomycin IV
Spectrum: Gram +ve (Enterococci, penicillin-resistant Streptococci, MRSA, CNS, and VRE)
Indications: Bacteremia, endocarditis, bone/joint, SSTI
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Gentamycin and Tobramycin are both "BLANKS"
Aminoglycosides
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Mechanism of action for Aminoglycosides
Inhibit protein synthesis by binding the 30S ribosomal subunit
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Are Aminoglycosides bacteriostatic or bactericidal?
Bactericidal
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Aminoglycosides are renally excretable and may cause the following toxicities (2)
1. Nephrotoxicity
2. Ototoxicity
15
Gentamicin and beta-lactams act synergistically against what?
Enterococci
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Spectrum and indications for Gentamicin IV
Spectrum: Gram -ve, Pseudomonas, synergy vs Streptococci and Enterococci with beta-lactam or vancomycin
Indications: Drug resistant UTI, combination therapy for Gram -ve sepsis, synergy for Gram +ve bacteremia and endocarditis
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Spectrum and indications for Tobramycin IV
Spectrum: Gram -ve, Pseudomonas (better than gentamicin)
Indications: Drug resistant UTI, combo therapy for serious Pseudomonas infections
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Azithromycin is a "BLANK"
Macrolide
19
Mechanism of action for Macrolides
Inhibit protein synthesis by binding the 23S rRNA in the 50S ribosomal subunit
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Macrolides are active against intracellular organisms, true or false?
TRUE
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Are Macrolides bacteriostatic or bactericidal?
Bacteriostatic
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Does Azithromycin have a long or short half life?
LONG
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Spectrum and indications for Azithromycin IV/PO
Spectrum: Mycoplasma, Chlamydophila, Legionella, M. catarrhalis, Chlamydia trachomatis, N. gonorrheae, MAC
Indications: Combo therapy for MAC Tx, MAC prophylaxis in HIV pt's, 2nd line for STI's, combo with beta-lactam for CAP
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Why is Azithromycin the preferred macrolide over erythromycin and clarithromycin? (5)
1. Broader spectrum
2. Fewer drug interactions
3. Once daily dosing
4. Tolerability
5. IV option
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Clindamycin is a "BLANK"
Lincosamide
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What is the mechanism of action of Clindamycin?
Inhibits proteins synthesis by binding to the 50S ribosomal subunit
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What is the bioavailability of Clindamycin?
Excellent
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Is Clindamycin bacteriostatic or bactericidal?
Bacteriostatic
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Clindamycin inhibits toxin production from what?
Group A Streptococcus
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Clindamycin is used in combination with what other antibiotic to treat necrotizing faciitis?
Penicillin
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Clindamycin is high risk for what?
C. difficile
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Spectrum and indications for Clindamycin PO/IV
Spectrum: Streptococci, S. aureus, MRSA (if susceptible), anaerobes
Indications: SSTI, bone/joint, abscesses, alternative for dental infections, polymicrobial infections in combo with Gram -ve agent, combo vs necrotizing faciitis
33
Doxycycline and Tigecycline fall under what family of antibiotics?
Tetracyclines/Glycylcyclines
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What is the mechanism of action of Tetracyclines/Glycylcyclines?
Inhibits protein synthesis by binding the 30S and 50S ribosomal subunits
35
Tetracyclines/Glycylcyclines are bacteriostatic, true or false?
TRUE
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Tetracyclines and Glycylcyclines are active against intracellular pathogens, true or false?
TRUE
37
Spectrum and indications for Doxycycline PO
Spectrum: Mycoplasma, Chlamydophila, Legionella, Chlamydia trachomatis, S. pneumoniae, Haemophilus, Moraxella, S. aureus (including MRSA)
Indications: COPD, CAP, Chlamydial STIs, purulent cellulitis (suspected MRSA)
38
Spectrum and indications for Tigecycline IV
Spectrum: Broad spectrum, Gram +ve (E. faecalis, MRSA), Gram -ve, anaerobes
Indications: Last line option of polymicrobial, multidrug resistant organisms if susceptibility confirmed
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3 problems with Tetracycline PO
1. Requires QID dosing on an empty stomach
2. Poorly tolerated
3. Narrower spectrum than Doxycycline
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Ciprofloxacin and Levofloxacin are both "BLANKS"
Fluoroquinolones
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What is the mechanism of action of Fluoroquinolones?
Inhibition of DNA gyrase and topoisomerase
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Bioavailability of Fluoroquinolones
EXCELLENT
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Are Fluoroquinolones bacteriostatic or bactericidal?
Bactericidal
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What 2 Fluoroquinolones are active against intracellular pathogens?
1. Levofloxacin
2. Moxifloxacin
45
Fluoroquinolones are high risk for C. difficile, true or false?
TRUE
46
Widespread use of Fluoroquinolones is leading to the development of resistance by which type of bacteria?
Gram -ve
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Spectrum and indications for Ciprofloxacin IV/PO
Spectrum: Gram -ve, Pseudomonas
Indications: Not usually 1st line due to increasing Gram -ve resistance, UTI, in combo with metronidazole or clindamycin for polymicrobial infections
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Spectrum and indications for Levofloxacin IV/PO
Spectrum: Streptococci, Mycoplasma, Chlamydophila, Legionella, Gram -ve
Indications: Not 1st line, reserve for suspected drug-resistant respiratory infections or allergy to 1st line agents.
49
Moxifloxacin is a respiratory fluoroquinolone, what is the risk of C. difficile with this drug?
High
50
Which Fluoroquinolone is active against multidrug resistant TB?
Moxifloxacin
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Which Fluoroquinolone has no Pseudomonas activity and does not get to therapeutic concentration in the urinary tract?
Moxifloxacin
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TMP-SMX and Nitrofurantoin are considered to be part of what family of antibiotics?
Anti-folates
53
Mechanism of action of Trimethoprim-sulfamethoxazole
Together they inhibit purine synthesis, preventing DNA synthesis
54
What is the mechanism of action of nitrofurantoin?
It is reduced inside the cell to produce reactive intermediates that cause cellular damage. There is minimal resistance due to complex mechanism.
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TMP/SMX acts as a "BLANK" agent
Bacteriostatic
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The bioavailability of TMP/SMX is...
EXCELLENT (PO)
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Nitrofurantoin is (bacteriostatic/bactericidal), and only achieves therapeutic concentrations in (urine/blood)
Bactericidal, Urine
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Nitrofurantoin is effective for cystitis, but not "BLANK"
Pyelonephritis
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Spectrum and indications for Trimethoprim/Sulfamethoxazole IV/PO
Spectrum: Gram -ve, S. aureus (MRSA), S. pneumoniae, Nocardia, Pneumocystis jiroveci
Indications: UTI (not first line), purulent cellulitis (MRSA), Nocardia infections, PCP Tx and prophylaxis
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Spectrum and indications for Nitrofurantoin PO
Spectrum: E. coli, Klebsiella, E. faecalis
Indications: 1st line for cystitis
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Metronidazole is in which family of antibiotics?
Nitroimidazoles
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What is the mechanism of action for Metronidazole?
It inhibits DNA synthesis
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What is the bioavailability of Metronidazole?
EXCELLENT - also has excellent penetration of the CNS
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What should you avoid when taking Metronidazole?
Alcohol (disulfiram reaction)
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Spectrum and indications for Metronidazole PO/IV
Spectrum: Anaerobes (including C. difficile), Protozoa (i.e. Giardia)
Indications: C. difficile, used in combo for polymicrobial infections/abscesses, trichomoniasis
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Linezolid belong to this class of antibiotics...
Oxazolidinones
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Mechanism of action for Linezolid
Inhibits protein synthesis by binding to 23S rRNA in 50S ribosomal subunit - prevents the formation of 70S ribosome.
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Bioavailability of Linezolid...
EXCELLENT
69
Linezolid is bacteriostatic/bactericidal...
Bacteriostatic
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What is there a risk of with prolonged use (> 2 weeks) of Linezolid?
Cytopenias
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Linezolid has activity against beta-lactam and vancomycin resistant organisms, true or false?
TRUE
72
Spectrum and indications for Linezolid PO/IV
Spectrum: Streptococci, Enterococci, Staphylococci, anaerobes
Indications: Resistance, allergy or failure with vancomycin therapy
73
Which 4 drugs were presented as anti-tuberculosis drugs?
1. Rifampin
2. Isoniazid
3. Pyrazinamide
4. Ethambutol
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The 4 drug combo used for TB is bacteriostatic/bactericidal?
Bactericidal
75
Anti-tuberculosis drugs are poorly absorbed, true or false?
FALSE
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Rifampin is a potent inhibitor/inducer of CYP 3A4?
Inducer
77
What type of toxicity should you monitor for when giving someone the empirical 4 drug combo for TB?
Hepatotoxicity
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Indications for Rifampin
Penetrates Staph biofilms, TB, MAC, latent TB Tx
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Indications for Isoniazid
TB and latent TB Tx
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Indications for Pyrazinamide
TB
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Indications for Ethambutol
TB, MAC
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How much can you save by switching to Geico?
15% or more
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