Antimicrobials Flashcards
prophylactic therapy
prevent infection or prevent dangerous disease in those already infected
preemptive therapy
early, targeted therapy, high-risk patients, asymptomatic but have become infected
empirical therapy
symptomatic patient but w/o identification of infecting organism
definitive therapy
infecting organism is known
post-treatment suppressive therapy
antimicrobial coverage at lower dose when infection is not completely eradicated
narrow-spectrum
act on a single or limited group of microorganisms
extended spectrum
active against G+ bacteria but also significant number of G- bacteria
broad-spectrum
act on a wide variety of bacterial species, G+ and G-
bacteriostatic
arrests growth (e.g. protein synthesis inhibitors)
bacteriocidal
kills bacteria (e.g. cell wall inhibitors) concentration or time-dependent
Beta-lactams
penicillins cephalosporins monobactam carbapenems MOA: covalently binds transpeptidase (PBP), preventing peptidoglycan cross-linking
penicillin G and V
natural penicillins
narrow, anti-streptococcal
nafcillin
narrow, anti-staphylococcal
“naf for staph”
aminopenicillins (ampicillin, amoxicillin)
extended, G+ and G-
H. influenzae, E. coli, Listeria, P. mirabilis, enterococci
HELP kill enterococci
anti-pseudomonal-piperacillin
broad
P. aeruginosa, Enterobacter, Proteus spp
cephalosporins (by generation)
1st gen: most narrow, good G+, modest G-, cephalexin cephalexin
2nd gen: increased G- activity
3rd gen: increased G- activity, decreased G+ activity, ceftriaxone (drug of choice for gonorrhea)
4th gen: extends beyond 3rd gen, useful in serious nosoccomial infections (e.g. Pseudomonas)
clavulonic acid
B-lactamase inhibitor (combined with amoxicillin)
vancomycin
MOA: inhibits transglycosylases, preventing polymerization of peptidoglycan sugar backbone
broad G+
C. difficile PO
fluoroquinolones
MOA: targets bacterial DNA gyrase
Concentration-dependent
Ciprofloxacin: broad G-, S. aureus, some Strep
Adverse effects: photosensitivity, Achilles rupture, contra-indicated in children
aminoglycosides
*bacteriocidal
gentamycin
MOA: binds 30S ribosome, interferes w/ initiation of protein synthesis, RNA misreading, concentration-dependent
Spectrum: aerobic G- bacteria
Adverse effects: ototoxicity, nephrotoxicity
tetracyclines
doxycycline
MOA: static, binds 30S ribosome, prevents acces of aminoacyl tRNA to acceptor (A) site
Broad G+ and G-, Rickettsia, Lyme’s disease
Adverse effects: photosensitivity, teeth discoloration, contra-indicated in children
macrolides
azithromycin
MOA: static, binds 50S ribosome, inhibits translocation
Spectrum: aerobic G+, some G-
Adverse effects: QT prolongation
clindamycin
MOA: binds 50S ribosome, inhibits translocation
Spectrum: pneumococci, S. pyogenes, viridans, Strep, MSSA, anaerobes (B. fragilis)
Adverse effects: pseudomembranous colitis
metronidazole
MOA: nitro radical anions damage DNA
Spectrum: anaerobes, C. difficile, giardia
Adverse effects: disulfiram-effect (inhibits acetaldehyde dehydrogenase, no EtOH 3 days post-administration)
acyclovir
for HSV and varicella
MOA: competes with deoxyGTP for DNA polymerase, cause DNA chain termination
azoles
antifungal
MOA: reduce production of egosterol
amphotericin B
antifungal
forms pores in cell membrane
Adverse effects: infusion related (fever, chills, vomiting, headache) and cumulative toxicity
Beta-lactams MOA
structural analogs of D-Ala-D-Ala, covalently bind transpeptidase (PBP), preventing peptidoglycan cross-linking
Beta-lactamase inhibitors
amoxicillin + clavulonic acid
ampicillin + sulbactam
piperacillin + tazobactam
PCN ADRs
allergic rxn: up to 10%
true anaphylaxis: up to .04%
NVD
pseudomembranis colitis
cephalosporin ADRs
1% cross-reactivity with PCN (if patient had anaphylaxis with PCN, don’t prescribe cephalosporin)
diarrhea
vancomycin ADRs
red-man syndrome
ototoxicity
nephrotoxicity
