EXAM 2 Antibiotics II Cont'd Flashcards
what is the mechanism of chloramphenicol?
inhibits 50S peptidyltransferase
describe the spectrum of chloramphenicol
broad spectrum
mostly bacteriostatic to all bacteria, except h. influenzae (bacteriocidal)
what is the clinical use of chloramphenicol?
restricted to life-threatening infections of h. influenzae, bacteriodes, rickettsia, and meningitis (serious infections where penicilin can’t be used due to allergy)
the utility of chloramphenicol is limited due to its severe ___
toxicity
does chloramphenicol cross the BBB?
yes
what are the adverse effects of chloramphenicol?
- hemolytic anemia, aplastic anemia (fatal), anemia, teratogenic, gray baby syndrome in premature infants
what are the serious drug interactions of chloramphenicol?
inhibits CYP450s to slow metabolism of warfarin, phenytoin (toxicity risk)
the mechanism of clindamycin is the same as ___
macrolides
it blocks peptide bond formation at the 50S subunit of bacterial ribosome (inhibits translocation step of protein synthesis)
___ is antagonistic if co-administered with macrolides
clindamycin
what is the spectrum of clindamycin?
- active against infections caused by non-enterococcal, gram + cocci
- no gram - activity
- bacteriostatic
urine levels of clindamycin are ___
non-therapeutic, so it is not good for UTIs
clindamycin can accumulate in patients with ___ or ___ failure
renal or liver
what are the adverse effects of clindamycin?
- pseudomembranous colitis - treated with oral vancomycin or metronidazole
- hematological disorders
- fever
- diarrhea
- cellulitis
what are the clinical uses for clindamycin?
- bone and joint infections
- anaerobes above the diaphragm
- gram + microbes
for patients with ___, clindamycin can be prescribed orally for months as an outpatient therapy
anaerobic aspiration pneumonia
what is the mechanism of linezolid?
binds to 50S subunit of bacterial ribosomes and blocks protein synthesis
what is the spectrum of linezolid?
- bactericidal (streptococci)
- bacteriostatic (enterococci and staphylococci)
what antibiotic has the following clinical uses?
treatment of vancomycin-resistant E. faecium
nosocomial pneumonia (both meth-susceptible and MRSA)
community acquired pneumonia
complicated skin infections caused by strep, staph, and MRSA
linezolid
what are the adverse effects of linezolid?
- generally well-tolerated with rare side effects
- hematologic (2.4% of patients)
- chronic treatment has resulted in reversible neurotoxicity
patients receiving adrenergic or serotinergic agents while taking linezolid may develop ___
serotonin syndrome
quinuprostin/dalfopristin is in what ratio?
30:70
the synergistic effect of quinuprostin/dalfopristin causes ___ to enhance quinuprostin binding
conformation change
what is the spectrum of quinuprostin/dalfopristin?
bacteriostatic
how should quinuprostin/dalfopristin be administered?
slow IV infusion only
no dose adjustment needed in renal insufficiency
what are the clinical uses for quinuprostin/dalfopristin?
- reserved for serious infections by multidrug resistant gram + organisms
- life threatening bacteremia VRE, enterococcus faecium, and complicated skin infections caused by MRSA and meth-resistant s. pyogenes
what are the adverse effects of quinuprostin/dalfopristin?
- local effects
- arthralgia and myalgia
- hyperbilirubinemia
what is the unique mechanism of mupirocin?
reversibly inhibits isoleucyl transfer-RNA synthetase enzyme which inhibits protein transaction
what is the spectrum of mupirocin?
bactericidal
how is mupirocin administered?
topically, but only small areas at a time
what are the clinical uses for mupirocin?
MRSA and meth-resistant s. pyogenes skin lesions
what are the adverse effects of mupirocin?
- application to large skin areas should be avoided in patients with renal insufficiency to avoid accumulation of polyethylene glycol used in ointment perparations
