Macrolides (Lec 14) Flashcards
Macrolides are produced by?
3 Macrolide drugs?
actinomycete bacteria, Streptomyces
erythromycin
clarithromycin
azithromycin
Macrolide antibiotic mechanism of action?
bind to 50S ribosomal subunits inhibiting protein synthesis
Macrolide active against?
Bacteriostatic or cidal?
G+
(U) static
Macrolide antibiotic spectrum?
similar to PCN G
Resistance to Macrolides develops how?
efflux pumps
Macrolide toxicity sxs? (4)
1) GI (erythro = most severe, clari = least)
2) allergy
3) hepatic
4) ototoxicity w/ IV erythro only
Erythromycin or Clarithromycin can adversely interact w/ other drugs how?
Inhibits CYP3A4 needed to metabolize other drugs ->
causes higher serum concentrations of those drugs
Erythromycin or Clarithromycin given w/ what drugs causes cardiac issues?
cisapride or pimozide
sparfloxacin or grepafloxacin
Azithromycin DOC for what bacteria? (2)
legionella (+rifampin)
chlamydia trachomatis
Clindamycin mechanism of action?
binds 50S subunit of rRNA -> inhibits protein synth
Clindamycin active against?
G+ cocci
G+ and G- anaerobes
Clindamycin side-effects? (2)
1) pseudomembranous colitis (c. diff)
2) rash
Dalfopristin and Quinupristin method of action?
Administered?
(streptogramins)
bind 50S ribosomal subunits -> inhibit protein synth
Administered together by IV
Dalfopristin/Quinupristin is -static or -cidal?
bactericidal
Oxazolidinones Prototype drug?
Linezolid
Linezolid active against?
G+ aerobes
VRE
MRSA
Linezolid should be last choice of tx for?
Multi drug resistant (MDR) strains
Clindamycin used to treat? (4)
1) toxic shock synd w/ vancomycin
2) osteomyelitis
3) toxoplasma encephalitis
4) MRSA
Dalfopristin and Quinupristin used to treat? (3)
1) vanco-resistant enterococcus faecium
2) Skin infections: MSSA, MRSA
3) PCN-resistant s. pneumoniae, MDR-strep
Oxazolidinones mechanism of action?
bind 23S rRNA of 50S subunit* ->
inhibits protein syth
(*unique binding site means no cross-resistance)
Linezolid inhibits?
monoamine oxidase (MAO)
Linezolid route of administration?
IV, oral
Linezolid drug interactions? (4)
1) β-blocker
2) MAO inhib
3) anesthesia
4) antidepressants
Erythromycin is prophylactic DOC for?
Pertussis