Antibiotics III: Inhibitors of Protein Synthesis Flashcards
aminoglycosides
gentamicin, amikacin, streptomycin, neomycin
target of aminoglycosides
G- organisms and G+ staph; concentration-dependent
active transport across plasma membrane into cytosol is O2-dependent
aminoglycosides
drugs that bind to 30-S
aminoglycosides
tetracyclines
drugs that bind to 50-S
erythromycin chloramphenicol clindamycin dalfopristin/quinupristin linezolid
long post-antibiotic effect (hours)
aminoglycosides
used for resistant bacteremia, sepsis and G+ endocarditis
aminoglycosides (in combo w/ beta-lactams or vancomycin)
second-line drug for active TB
streptomycin
used in hospitals where resistance to gentamicin and tobramycin is common
amikacin
adverse reactions to aminoglycosides
ototoxicity, nephrotoxicity
prototype tetracycline
doxycycline
prototype glycylcycline
tigecycline
tetracycline resistance
increased drug efflux and production of proteins that interfere w/ drug binding to 30S subunit (tigecycline resistant to efflux)
distributed widely in bone and teeth
tetracyclines
form insoluble chelates with multivalent cations resulting in decreased oral absorption
tetracyclines
treatment and prophylaxis of malaria
tetracyclines
broad spectrum against aerobic and anaerobic G+ and G- organisms (use declined due to resistance, toxicity)
tetracyclines
effective against rickettsial infections, Chlamydia, Lyme disease, anthrax, Mycoplasma pneumonia
tetracyclines
adverse effects include discoloration of teeth, renal toxicity, superinfection, hepatotoxicity, photosensitivity
tetracyclines
macrolides
erythromycin
azithromycin
bacteriostatic (can be bactericidal against highly susceptible strains, high concentrations)
macrolides
binds reversibly to 50S; inhibits translocation step of protein elongation
macrolides
Resistance: plasmid-encoded methylation of 50S subunit that decreases binding affinity
macrolides
used for atypical pneumonias, Bordatella pertussis, diphtheria, chlamydia
macrolides
Adverse reactions: cholestatic hepatitis, prolonged Q-T interval
macrolides
MOA: similar to macrocodes; block peptide bond formation through interactions at A-site and P-site of 50S
clindamycin
Uses: severe group A strep, gas gangrene; b. fragilis; topical for acne
clindamycin
Adverse reaction: CDAD
clindamycin (and ciprofloxacin)
MOA: binds to peptidyl transferase center of 50S subunit
chloramphenicol
broad-spectrum bacteriostatic against G+ (MRSA), G- and anerobes
chloramphenicol
resistance due to acetyltransferase that acetylates the drug
chloramphenicol
Adverse reactions: gray baby, bone marrow suppression, aplastic anemia
chloramphenicol
MOA: binds to unique site of 23S rRNA of 50S subunit and blocks formation of initiation complex (bacteriostatic)
linezolid
Uses: VRE and MRSA
linezolid
Adverse reactions: myelosupression (weekly blood tests); neuropathy
linezolid
Drug interactions w/ MAOIs and SSRIs
linezolid
MOA: inhibits peptidyl transferase center of 23S rRNA (50S) and binds same site as macrolides
quinupristin-dalfopristin
streptogramins
quinupristin-dalfopristin
approved for serious infections caused by VRE
quinupristin-dalfopristin
Adverse reactions: hyperbilirubinemia, arthralgia/myalgia
quinupristin-dalfopristin
