Sulfonamides (Lec 17) Flashcards
Sulfa drugs are derivatives of what?
benzene:
substitution at amino group
Sulfa drug mechanism of action?
all have same bacteriostatic action:
bind to free para amino group,
blocks PABA from binding,
stops formation of folic acid
Trimethoprim drug mechanism?
stop reduction of dihydrofolate to tetrahydrofolate
Co-trimoxazole and Bactrim are?
sulfamethoxazole + trimethoprim
Sulfa drug active against?
G+ and G- (bacteriostatic)
DOC for UTI?
Co-trimoxazole
Sulfa administration?
oral
IV
Sulfa absorption?
very high in urine
can cross placenta, blood-brain and mammary barriers
Sulfa side-effects?
Allergy
Steven-Johnson synd
Kernicterus (bind bilirubin)
All systems, esp liver/kidneys
Lipopeptide Abx are?
cyclic lipoproetins
Daptomycin
Daptomycin mechanism?
Binds membrane ->
rapid depolarizes memb potential ->
inhibits everything (cidal)
Does not penetrate bacteria cytoplasm
Daptomycin active against?
G+ aerob and anaerobe
including MRSA, MSSA
Daptomycin route of administration?
IV
Daptomycin suitable empiric tx for?
serious G+ infections
alternate to vancomycin
Mupirocin (Bactroban) made from?
pseudomonas fluorescens
structurally different from ALL other abx
Mupirocin mechanism?
inhibit protein and RNA synth
static or cidal depending on [drug]
Mupirocin active against?
G+ and G-
little chance of cross-resistance to other abx cuz mechanism unique
Mupirocin DOC for what infection?
impetigo:
s areus, strep pyognes
Also treats MRSA in nasal passages
Polypeptide Abx: Polymyxin B
mechanism?
binds memb phospholipid A ->
↑ permeability ->
loses metabolites
Polypeptide Abx: Polymyxin B
active against?
G- bacilli
EXCEPT proteus and neisseria
Polypeptide Abx: Polymyxin B not effective against G+, why?
lacks endotoxins
Polypeptide Abx: Polymyxin B administered?
topically
Polypeptide Abx: Polymyxin B
side-effects?
nephrotoxicity if taken orally
