antibiotics 2 Flashcards
importance of D-alanine
amino acid that combines with other amino acids to create a polypeptide that helps the peptidoglycan unit attach to other PG units, leading to PG later of cell wall
vancomycin
glycopeptide
telavancin
glycopeptide
what abx inhibits cell wall synthesis by binding to D-ala D-ala and prevents the formation of peptidoglycan and phospholipids
glycopeptides
bactericidal
how are we seeing resistance against glycopeptides
alternation of binding site to D-ala-D-Lac
seen in VRE
what type of bacteria does vancomycin kill?
g+
NO G-
Main indications of vancomycin
S. aureus (MRSA)
Clostridium (C. diff)
what is the main tx of MRSA for inpatient therapy
vancomycin
you must adjust vancomycin for…
renal impairment
vancomycin dosing is based upon…
CrCL and TBW
impaired renal function = less frequent dosing intervals
how do you monitor vancomycin for severe MRSA infections
area under the curve (AUC) calculations
using vancomycin for other infection (not severe) you base the dosing based upon…
trough levels
when is vancomycin monitoring not needed?
uncomplicated skin/soft tissue infections in non-obese pts who have normal renal function
trough level adjustments of vancomycin is measured ____ prior to next infusion after steady state is reached
30 mins
normal renal function - after 4th dose
impaired - assess “spot” serum conc until renal function stabilizes
for AUC level adjustments for vancomycin, trough levels are obtained _____, peak levels are obtained ______
30 mins before dose
1-2hrs after dose
adverse effects of vancomycin
- hyperemia (Red man syndrome)
- nephrotoxicity/ototoxicity
how do you avoid hyperemia when using vancomycin
do slow infusions (1-2h)
what can you give to preteat hyperemia when prescribed vancomycin
antihistamines
nephrotoxicity/ototoxicity is more likely with vancomycin when it’s combined with ?
aminoglycosides
what alternatives of vancomycin can be used for MRSA infections
- televancin - no VRE
- dalbavancin - no VRE
- oritavancin
- daptomycin
- linezolid
what alternative use of vancomycin is also the best choice for VRE infection
daptomycin
gentamicin
aminoglycoside
tobramycin
aminoglycoside
amikacin
aminoglycoside
streptomycin
aminoglycoside
MOA of aminoglycosides
inhibits bacterial protein synthesis - binds to the 30S subunit
bactericidal
4 modes of resistance of aminoglycosides
- chromosomal mutation
- enzymatic destruction of drug
- lack of permeability through cell wall
- efflux pump
spectrum of aminoglycosides
g-
mycobacterium tuberculosis
NO G+
Aminoglycosides are most frequently used in combo with ?
aminoPCN
(ampicillin + gentamicin)
how do you monitor aminoglycosides?
- monitor peak and troughs
- BUN/Cr
- audiometry
same precautions as vancomycin
doxycycline
tetracycline
minocycline
tetracycline
MOA of tetracyclines
inhibits bacterial protein synthesis - binds to 30S ribosomal subunit, blocks tRNA
bacteriostatic
2 modes of resistances of tetracyclines
- active efflux
- enzymatic deactivation
spectrum of tetracyclines
- g+
- g-
- atypicals - mycoplasma, rickettsiae, chlamydiae, spirochetes
includes MRSA
first line and additional treatments of tetracyclines
- lyme disease
- rocky mountain spotted fever
- cholera
- acne
additional - chlamydia, CAP (empiric)
contraindications for tetracyclines
- children <8-9 y/o (<13 not as bad)
- tooth discoloration - pregnancy/nursing
- hepatotoxicity
- tooth discoloration (baby)
- fetal long bone growth impairment
what should you avoid while taking tetracyclines
- antacids
- dairy products
limits absorption
adverse effects of tetracyclines
- GI distress
- hepatotoxicity
- photosensitivity
- vertigo - especially minocycline
- C. diff
erythromycin
macrolide