ABx for staph and strep Flashcards
What is the MOA of Daptomycin?
rapidly disrupts bacterial cell membranes
What are the results of the MOA of daptomycin?
depolarization and loss of membrane potential and K+ efflux
resistance to daptomycin?
rare due to bactericidal (none known)
When should daptomycin be administered?
infused 1x/day after hemodialysis
why can daptomycine not be given IM?
direct muscle toxicity
What is significant about the metabolism of daptomycin?
90% bound to albumin
How is daptomycin eliminated? dose adjustments necessary?
renal; dosage adjustment for renal deficiency only
What are ADEs with daptomycin? How can they be monitored?
muscle pain/weakness=> serum creatine phosphokinase elevations
Are there drug interactions with daptomycin?
none with P450s
caution w/ -statin use
What are the Tx uses for daptomycin?
aerobic gram +; MDR gram +; MSSA, MRSA bacteremia; skin/soft tissue infections
What disease and why should daptomycin not be used in?
pneumonia as surfactant antagonizes daptomycin
What is the MOA of oxazolidinones-linezolid?
inhibits protein synthesis by binding to 23S RNA on 50 ribosomal subunit
oxazolidinones-linezolid has static effects on which bugs? cidal effects?
static=> staph, entero
cidal=> strep
How does resistance occur with oxazolidinones-linezolid?
point mutation in 23S RNA (entero and S. aureus)
What are the FDA approved indications for oxazolidinones-linezolid?
PRSA; MRSA; resistant s. epi; Enteroccus faecium and faecalis; reserve for serious VRE infections
How should oxazolidinones-linezolid be administered?
orally or parenteral but food delays absorption=> supplemental doses after hemodialysis
How is oxazolidinones-linezolid metabolized?
non enzymatic oxidation with 2 inactive metabolites=> no CYP interactions
Elimination of oxazolidinones-linezolid?
both non-renal and renal mechanisms
ADEs for oxazolidinones-linezolid?
well tolerated but common are diarrhea, headache, nausea, vomiting; myelosuppression in Tx longer than 2 wks
other than myelosuppresion, what else is associated with Tx longer than 2 wks with oxazolidinones-linezolid?
reversible thrombocytopenia, anemia, neutropenia; optic and peripheral neuropathy; lactic acidosis
What is a warning patients must receive with oral admin of oxazolidinones-linezolid?
contains aspartame so PKU patients need warning
What are the associated DDIs with oxazolidinones-linezolid?
non selective inhibitor of MAO so caution used=> HTN from decreased breakdown
Rifampin MOA
inhibits DNA dependent RNA polymerase
What is the most active anti-leprosy drug at present time?
rifampin
What is the MOA for clindamycin?
inhibition of protein synthesis by binding to 50S subunit of ribosome
When is clindamycin not affected?
when given with erythromycin
Is clindamycin static or cidal?
either depending on concentration
resistance to clindamycin?
slowly due to decreased affinity of drug for the ribosome
What is the Tx use for clindamycin?
anaerobes (G+ & G-); peptostreptococci, actinomyces; bacteroides fragillis; G+ cocci (MRSA, group A strep)
clindamycin absorption
nearly complete orally and acid stabile but delayed by food
clindamycin distribution
widely into bone and abscesses=> NOT in CSF or intracellular
clindamycin in pregnancy
crosses placenta and found in breast milk
clindamycin metabolism
liver to inactive forms
clindamycin dose adjustment
patients with liver disease but NONE with renal disease
clindamycin excretion
bile and urine but not removed by hemodialysis
ADEs of clindamycin
pseudomembranous colitis from clostridium difficile; GI disturbances; hypersensitivity rashes
What should you treat pseudomembranous colitis from clindamycine use?
metronidazole or vancomycin
When can clindamycin be used prophylactically?
patient is allergic to penicillin w/ associated strep and staph infections like MRSA, MSSA
clindamycin and pyrimethamine treat what specific subset of patients
toxoplasmosis in patients with AIDS
What is the MOA for mupirocin?
inhibits protein and RNA synthesis=> binds reversibly to staph tRNA synthetase
mupirocin cidal or static
concentration dependent
mupirocin Tx uses
G+ (staph and strep); MRSA; impetigo
Absorption of mupirocin
topically absorption is limited and quickly inactivated
What is significant about the vehicle for mupirocin delivery in ointment?
polyethlyene glycol may cause renal failure
What is the MOA for bacitracin?
inhibits bacterial cell wall synthesis by blocking inside to out dephosphorylation of carrier protein
Tx uses for bacitracin
G+ cocci and baccili
What is an ADE with parenteral use?
nephrotoxicity
What is bacitracin typically found with in ointment?
neomycin and polymyxin B
