Antibacterial Therapy II Flashcards
Glycopeptides MOA
- Vancomycin
- inhibit bacterial CW synthesis
- earlier point than beta lactams
- prevent incorporation of subunits into peptidoglycan
Lipopeptides MOA
- Daptomycin
- disrupt bacterial cell membrane
- cause depolarization of cell membrane
- calcium dependent
- bactericidal
Glycopeptides/Lipopeptides Special Considerations
- bactericidal
- vancomycin is slowly tidal
- vancomycin not well absorbed orally
- daptomycin inactivated by lung surfactant - not effective vs. pneumonia
Vancyomycin
Glycopeptide
S: Enterococci, Penicillin R Streptococci, MRSA, CNS, C. diff
CI: Bacteremia, pneumonia, endocarditis, bone & joint ix’s, SSTI’s, C. diff ix’s (orally)
Daptomycin
Lipopeptide
S: Enterococci, Penicillin R. Streptococci, MRSA, CNS, vancomycin R organisms
CI: Bacteremia, endocarditis, SSTI, bone and joint ix’s
Aminoglycosides MOA
- inhibit protein synthesis
- bind 30S subunit
Aminoglycosides Special Considerations
- bactericidal
- renally eliminated
- nephrotoxicity
- ototoxicity
- Gentamicin synergy w/ beta lactams vs. Enterococci
Gentamicin
Aminoglycoside
S: G-, Pseudo, Enterococci and Streptococci (w/ beta lactams)
CI: bacteremia, G- sepsis, drug resistant UTI
Tobramycin
Aminoglycoside
S: G-, Pseudo (better than gentamicin)
CI: combo therapy vs. Pseudo, drug R UTI
Macrolides MOA
- inhibit protein synthesis
- bind 23S subunit
Macrolides Special Consideration
- bacteriostatic
- active vs IC organisms
- azithromycin has long half life
Azithromycin
Macrolide
S: Mycoplasma, Chlamydophila, Moraxella catarrhalis, Legionella, Neisseria gonorrhea, MAC, Chlamydia trachomatis
CI: combo tx for MAC, MAC prophylaxis in HIV pt’s, second line for STI’s, combo w/ beta lactams vs. CAP
Azithromycin preferred over erythromycin and clarithromycin. Why?
- fewer drug interactions
- once daily oral dosing
- broader spectrum
Lincosamide MOA
- inhibit protein synthesis
- binds 50S subunit
Lincosamide Special Considerations
- bacteriostatic
- high bioavailability
- high risk of C. diff
Clindamycin
Lincosamide
S: Streptococci, MRSA, S. aureus, anaerobes
CI: abscesses, SSTI, bone and joint ix’s, polymicrobial ix’s, combo w/ penicillin for NF
Tetracyclines and Glycylcyclines MOA
- inhibit protein synthesis
- bind 30S and 50S subunits
Tetracyclines and Glycylcyclines Special Considerations
- active vs. IC organisms
- bacteriostatic
Doxycycline
Tetracycline
S: Legionella, M. catarrhalis, Chlamydophila, C. trachomatis, Mycoplasma, S. pneumo, H. influenzae
CI: CAP, COPD, chlamydial STI’s
Tigecycline
Glycylcycline
S: Broad spectrum, G+, G-, anaerobes
CI: last line of polymicrobial, MDR ix’s if susceptible
Tetracycline
- requires QID dosing on empty stomach
- poorly tolerated
- narrower spectrum than doxycycline
Fluoroquinolones MOA
-inhibit DNA gyrase and topoisomerase
Fluoroquinolones Special Considerations
- high bioavailability
- bactericidal
- increasing levels of resistance
- levo and moxi active vs. IC organisms
- high risk of C. diff
Ciprofloxacin
Fluoroquinolone
S: G-, Pseudo
CI: not first line (increasing resistance), UTI’s, combo w/metronidazole or clindamycin vs. polymicrobial ix’s
Levofloxacin
Fluoroquinolone
S: Streptococci, Mycoplasma, Chlamydophila, Legionella, G-
CI: suspected drug resistant respiratory ix’s
Moxifloxacin
- respiratory quinolone
- others preferred
- high risk of C. diff
- active vs. MDR tuberculosis
Trimethoprim-Sulfamethoxazole MOA
- inhibits folate production, purine synthesis
- inhibits dihydropteroate synthase and dihydrofolate reductase
Nitrofurantoin
- reduced IC’ly into reactive intermediates that damage proteins, RNA
- complex mechanism, minimal resistance
TMP-SMX Special Considerations
- bacteriostatic
- high oral bioavailability
- increasing S. pneumo and E. coli resistance
Nitrofurantoin resistance
- only reaches therapeutic levels in urine
- bactericidal
- effective for cystitis, not pyelonephritis
TMP-SMX
Anti-folate
S: S. pneumo, S. aureus (MRSA), PJP, G-
CI: PJP prophylaxis, UTI, purulent cellulitis
Nitrofurantoin
Anti-folate
S: E. coli, E. faecalis, Klebsiella
CI: 1st line for cystitis
Nitroimidazole MOA
-inhibit DNA synthesis
Nitroimidazole Special Considerations
- high bioavailability
- high CNS penetration
- disulfram reaction with alcohol
Metronidazole
Nitroimidazole
S: anaerobes, including C. diff, protozoa (eg. Giardia)
CI: C. diff ix’s, polymicrobial ix’s, trichomoniasis
Oxazolidinone MOA
- inhibit protein synthesis
- binds 30S subunit
Oxazolidinone Special Considerations
- activity vs. beta lactam and vancomycin resistant organisms
- high bioavailability
- bacteriostatic
- cytopenias with prolonged therapy
Linezolid
Oxazolidinone
S: Streptococci, Enterococci, Staphylococci, anaerobes
CI: failure w/ vancomycin therapy
Anti-tuberculous drugs Special Considerations
- four drug combo therapy due to increasing resistance
- bactericidal
- well absorbed
- rifampin induces CYP 3A4
- monitor for hepatotoxicity
Four Anti-tuberculous drugs
Rifampin*
Ethambutol*
Pyrazinamide
Isoniazed
*active vs. MAC as well
