Antimicrobial Flashcards
inhibit bacterial cell-wall synthesis
penicillin cephalosporins imipenem/meropenem aztreonam vancomycin
inhibit bac protein synthesis
aminoglycosides chloramphenicol macrolides tetracyclines streptogramins linezolid
inhibit nucleic synthesis
fluoroquinilones
rifampin
inhibit folic acid synthesis
sulfonamides
trimethoprim
pyrimethamine
penicillin MoR
- B-lactamases – drugs are either resistant or sensitive
- change target (PBP)
- prevent entry (porin structure)
narrow spectrum, B-lactamase sensitive, penicillin
pen G and pen V
for: strep, pneumo, meningococci, Treponema pallidum
very narrow spectrum, B-lactamase resistant, penicillin
naficillin, methicillin, oxacillin
for: staphylococci
only B-lactamase resistant penicillins
naficillin, methicillin, oxacillin
broad spectrum, B-lactamase sensitive, penicillin
ampicillin, amoxicillin
for: gram (+) cocci, E coli, H influenzae, Listeria, Borrelia burgdorferi, H pylori
treat listeria with
ampicillin
treat Borrelia burgdorferi and H pylori with
amoxicillin
extended spectrum, B-lactamase sensitive, penicillin
ticarcillin, pipercillin
for: gram (-), Pseudomonas
clavulanic acid and sulbactam are
B-lactamase inhibitors
nafcillin and oxacillin are eliminated
in bile
active tubular secretion of penicillins in blocked by
probenecid
ampicillin is metabolized by
enterohepatic cycling
1st gen cephalosporin
cefazolin, cephalexin
2nd gen cephalosporin
cefotetan, cefaclor, cefuroxime
3rd gen cephalosporin
ceftriaxone (IM), cefotaxime (parenteral), cefdinir, cefixime (oral)
4th gen cephalosporin
cefepime
ceftriaxone is eleminated
in the bile – don’t give to neonates
cefazolin, cephalexin used for
gram (+) cocci, E coli, Klebsiella, pneumoniae, Proteus, surgical prophylaxis
cefotetan, cefaclor, cefuroxime used for
increased gram (-) coverage, some anaerobes
cephalosporins that enter CNS
cefuroxime (2nd gen), most 3rd gens, cefepime (4th gen)
ceftriaxone, cefotaxime, cefdinir, cefixime used for
gram (+) and gram (-) cocci, Neisseria gonorrhea, gram (-) rods, meningitis, sepsis
cefepime
widest spectrum
which cephalosporins are resistant to B-lactamase?
3rd and 4th gen
penems are resistant/sensitive to B-lactamases?
resistant
penems are used for
gram (+) cocci, gram (-) rods (enterobacter and pseudomonas) and anaerobes
What is cilastatin do?
inhibits imipenem from being metabolized to a nephrotoxic metabolite
SE of penems
seizures in patients with renal dysfunction
aztreonam
for gram (-) rods
**has no cross-allergenicity
vancomycin binds
D-ala-D-ala muramyl pentapeptide
vancomycin spectrum
MRSA, enterococci, C diff
MoR to vancomycin
D-ala –> D-lactate
vancomycin side effects
“red man syndrome” from histamine release when given too rapidly, ototoxicity, nephrotoxicity
interfere with initiation codon function
aminoglycosides (30S) and linezolid (50S)
block docking of tRNA (amino acid incorporation)
tetracyclines (30S) and dalfopristin/quinupristin (50S)
blocks peptidyl transferase movement from P site to A site (formation of a peptide bond)
chloramphenicol (50S)
blocks translocation of peptidyl-tRNA from A to P
macrolifes and clindamycin (50S)
30S inhibitors
aminoglycosides and tetracyclines
aminoglycoside spectrum
gram (-) rods
aminoclycoside bactericidal/bacteristatic
bactericidal
aminoglycoside uptake involves
O2-dependent, therefore anaerobes are innately resistant
aminoglycoside side effects
nephrotoxic (enhanced by vancomycin, amphotericin B, cisplatin, and cyclosporine), ototoxic (enhanced by loop diuretics), NM blockade with decreased release of ACh (enhances effects of muscle relaxants)
specific aminoglycosides
gentamicin, tobramycin, amikacin –> gram (-) rods
streptomycin –> TB, bubonic plague, tularemia
tetracycline spectrum
chlamydial and mycoplasmal species, H. pylori, Rickettsia, Borrelia burgdorferi, Brucella, Vibrio, and Treponema
tetracucline uptake is decreased by
dairy products
tetracycline side effects
tooth enamel dysplasia, decreased bone growth in children, phototox, GI distress
doxycycline
prostatitis
minocycline
high concentrations in tears and saliva, used in meningococcal carrier state
demclocycline
SIADH
tigecycline
resistant gram (+) MRSA and VREF, gram (-), anaerobes
rash on neck and forearms indicates
phototoxicity by tetracyclines, sulfonamides, or quinolones
contraindicated in pregnancy
aminoglycosides, fluoroquinolones, sulfonamides, tetracyclines
chloramphenicol spectrum
backup drug for Salmonelle typhi, B fregilis, Rickettsia, bac meningitis
chloramphenicol inhibits
cytochrome p450
chloramphenicol side effects
bone marrow suppression
“gray baby” because no glucuronosyl transferase
macrolides (50S)
erythromycin, azithromycin, clarithromycin,
macrolide spectrum
gram (+) cocci, atypical organisms, Legionella, Campylobacter, Mycobacterium avium-intracellulare, H pylori
macrolides inhibit
p450
macrolide side effects
stimulate motilin receptors, reversible deafness, increased QT interval
clindamycin
gram (+) cocci, anaerobes
SE pseudomembranous colitis
linezolid mechanism
prevents the formation of N-formylmethionyl-tRNA-ribosome-mRNA ternary complex
linezolid spectrum and side effects
VRSA, VRE, drug-resistant pneumococci
causes bone marrow suppression
quinupristin/dalfopristin
block tRNA docking
used for VRSA, VRE
4 organisms not covered by cephalosporins
Listeria
Atypicals
MRSA
Enterococci
inhibitors of folic acid synthesis
sulfonamides, trimethoprim, pyrimethamine
sulfonamides inhibit
dihydropteroate synthetase (enzyme only in bacteria)
trimethoprim and pyrimethamine inhibit
dihydrofolate reductase
sulfasalazine is a prodrug for
ulcerative colitis and RA
trimethoprim-sulfamethoxazole uses
bacteria, fungi - Pneumocystis jiroveci, protozoa - toxoplasma gondii
bacteria covered by trimethoprim-sulfamethoxazole
Nocardia, listeria, gram (-) infections – UTIs, gram (+) infections
sulfonamides, trimethoprim, pyrimethamine have high/low protein binding
high protein binding –> drug interactions!!
sulfonamides side effects
Steven-Johnson syndrome, hemolysis in G6PD deficiency, phototoxicity
trimethoprim or pyrimethamine side effects
bone marrow suppression
inhibitors of nucleic acid synthesis
quinolones, “floxacins”
quinolones inhibit
topoisomerase II and topoisomerase IV
quinolones are used for
UTIs, STDs, diarrhea due to CHielle, Salmonella, E coli, Campylobacter, drug-resistant pneumonia
quinolone absorption is inhibited by
iron and Ca
side effects of quinolones
tendonitis. phototox, CNS, contraindicated in pregnancy and kids
metronidazole mechanism
converted to free radicals by ferredoxin
use for metronidazole
antiprotozoal, anaerobic gram (-)
metronidazole side effects
metallic taste, disulfiram-like effect (patients shouldn’t drink alcohol)
antibiotics for H pylori
MCAT (metronidazole, clarithromycin, amoxillin, tetracycline)
isoniazid inhibits
mycolic acid synthesis
isoniazid is converted by
catalase
which vitamin should be given with isoniazid
vit B6 - to prevent peripheral neuritis and sideroblastic anemia
isoniazid can cause
hepatitis, SLE
rifampin inhibits
DNA-dependent RNA polymerase
rifampin side effects
p450 inducer, red-orange metabolites, hepatitis
ethambutol inhibits
synthesis of arabinogalactan in the cell wall
ethambutol side effects are
dose dependent retrobulbar neuritis aka red-green color blindness and decreased visual acuity
pyrazinamide can cause
hyperuricemia, hepatitis
streptomycin, a protein synthesis inhibitor, can be used to treat
TB
streptomycin can cause
deafness, vestibular dysfunction, nephrotoxicity, muscle weakness