antibiotics Flashcards
penicillin moa
bind PBPs (transpeptidases) and block transpeptidase cross-linking for peptidoglycan; activate autolytic enzymes
penicillin clinical use
gram +, neisseria meningitidis, and syphilis
penicillin tox
hypersensitivity reactions, hemolytic anemia
penicillin resistance
penicillinase in bacteria (beta-lactamase) cleaves beta-lactam ring
aminopenicillins (drugs)
amoxicillin, ampicillin
aminopenicillin clinical use
extended-specturm penicillin - H. flu, e. coli, listeria, proteus, salmonella, shigella, enterococci
penicillinase resistant penicillins
oxacillin, nafcillin, dicloxacillin
penicillinase resistant penicillin clinical use
s. aureus
aminopenicillin resistance
penicillinase in bacteria (beta-lactamase) cleaves beta-lactam ring
penicillinase resistant penicillins mechanism
binds PBPs; bulky R group blocks access of beta latamase to the beta lactam ring
beta-lactamase inhibitors
clavulanic acid, sulbactam, tazobactam
first generation cephalosporins (drugs)
cefazolin and cephalexin
1st gen cephalosporins use
proteus, e.coli, klebsiella, gram + cocci
2nd gen cephalosporin drugs
cefoxitin, cefaclor, cefuroxime
2nd gen cephalosporin use
h. flu, enterobacter, neisseria, proteus, E.coli, klebsiella, serratia, Gram + cocci
3rd gen. cephalosporin drugs
ceftriaxone, cefotaxiime, ceftazidime
3rd gen cephalosporin use
serious gram negative infections resistant to other beta lactams
ceftriaxone: meningitis and gonorrhea
ceftazidime: pseudomonas
4th gen cephalosporin drug
cefepime
cefepime use
pseudomonas and gram +
5th generation cephalosporin drug
ceftaroline
ceftaroline use
broad gram + and gram - coverage, including MRSA; does not cover pseudomonas
cephalosporin toxicity
hypersensitivity, vit K deficiency, low cross-reactivity with PCN, increased nephrotoxicity of aminoglycosides
aztreonam moa
monobactam resistant to beta lactamases; prevents peptidoglycan crosslinking by binding PBP-3; synergistic with ahminoglycosides
aztreonam use
gram negative rods only; no activity against gram + or anaerobes; nontoxic
carbapenems drugs
imipenem, meropenem, ertapenem, doripenem
carbapenem moa
broad-spectrum beta-lactamase resistant
imipenem administration
must be given with cilastatin (inhibitor of renal dehydropeptidase I) to decrease inactivation of the drug in renal tubules
carbapenem clinical use
gram + cocci, gram-neg. rods and anaerobes; wide spectrum;
carbapenem toxicity
GI, skin rash, CNS toxicity, seizures (esp. meropenem)
vancomycin moa
inhibits cell wall synthesis by binding D-ala D-ala portion of cell wall precursors
vancomycin clinical use
gram + only; MRSA, enterococci, and C. difficile
vancomycin toxicity
nephrotoxicity, ototoxicity, thrombophlebitis, diffuse flushing - red man syndrome
vancomycin resistance
modification of D-ala D-ala to D-ala D-lac
aminoglycosides drugs
gentamicin, neomycin, amikacin, tobramycin, streptomycin
aminoglycoside moa
inhibit formation of initiation complex and cause misreading of mRNA; also block translocation;
aminoglycoside use
severe gram neg. rod infection; require O2 for uptake so ineffective against anaerobes;
neomycin for bowel surgery
aminoglycoside resistance
bacterial transferase enzymes inactivate the drug by acetylation, phosphorylation, or adenylation
tetracyclines drugs
tetracycline, doxycycline, minocycline
tetracycline moa
bind 30S and prevent attachment of ammoniacal-tRNA; limited CNS penetration;
doxycycline metab
fecally eliminated so it can be used in renal failure; do not take with milk or antacids (Ca or Mg) or iron preparation because divalent cations inhibits its absorption in the gut
tetracycline use
intracellular microbes: borrelia burgdorferi, m. pneumoniae, rickettsia, and chlamydia; can be used to treat acne
tetracycline toxicity
GI, discoloration of teeth and inhibition of bone growth in children, photosensitivity; contraindicated in pregnancy and children
tetracycline resistance
decreased uptake or increased efflux out of bacterial cells by plasmid-encoded transport pumps
macrolides drugs
azithromycin, clarithromycin, erythromycin
macrolide moa
bind to the 23S of the 50S and block translocation
macrolide use
atypical pneumonias, STDs, and pram + cocci
macrolide toxicity
GI motility issues, arrhythmia due to QT prolongation, acute cholestatic hepatitis (erythromycin), rash, eosinophilia, cyp inhibition
macrolide resistance
methylation of the 23S rRNA-binding site
chloramphenicol moa
blocks peptidyltransferase at 50S
chloramphenicol use
limited due to toxicity; meningitis and RMSF
chloramphenicol toxicity
anemia, aplastic anemia, gray baby syndrome,
chloramphenicol resistance
plasmid-encoded acetyltransferase inactivates the drug
clindamycin moa
blocks peptide transfer at 50S
clindamycin use
anaerobic infections in aspiration pneumonia, lung abscesses, and oral infections; also invasive GAS infections
clindamycin toxicity
pseudomembranous colitis, fever, diarrhea
sulfonamides drugs
sulfamethoxazole, sulfisoxazole, sulfadiazine
sulfonamide moa
inhibit folate synthesis; para-aminobenzoic acid (PABA) antimetabolites inhibit dihydropteroate synthase
sulfonamides use
gram +, gram-, nocardia, chlymidai; simple UTI
sulfonamides toxicity
hypersensitivity reactions; hemolysis in G6PD deficient, nephrotoxic (tubulointerstitial nephritis), photosensitivity, kernicterus in infants, displaces other drugs from albumin (e.g. warfarin) causing increased drug levels
sulfonamide resistance
altered enzyme (bacterial dihydropteroate synthase), decreased uptake, or increased PABA synthesis
trimethoprim moa
inhibits DHFR
trimethoprim use
used with sulfonamides, never alone;
UTIs, shigella, salmonella,
pneumocystis jirovecii and toxoplasmosis prophylaxis in AIDS
trimethoprim toxicity
megaloblastic anemia, leukopenia, granulocytopenia
fluoroquinolones drugs
ciprofloxacin and other -floxacin drugs
fluoroquinolone moa
inhibts DNA gyrase (topo II) and topo IV; cannot be used with antacids
fluoroquinolone use
gram negative rods of urinary and GI tracts including pseudomonas, neisseria; some gram + organisms
fluoroquinolone toxicity
GI, superinfection, tendonitis, tendon rupture, leg cramps, myalgias
contraindicated in pregnancy
some cause QT prolongation
Fluoroquinolone resistance
chromosome-encoded mutation in DNA gyrase, plasmid-mediated resistance, efflux pumps
metronidazole moa
forms free radical toxic metabolites in the bacteria cell that damage DNA
metronidazole toxicity
disulfiram-like reaction with alcohol, metallic taste
metronidazole use
GET GAP on the metro: guard, entamoeba, trichomonad, gardeners vaginalis, anaerobes (bacteroides and c. diff) H. pylori
linezolid moa
binds 23S of 50S
linezolid use
VRE and MRSA
linezolid toxicity
serotonin syndrome