From Jen: Antimicrobials Flashcards
(27 cards)
Bacteriostatic Drugs
Erythromycin Clindamycin Sulfamethoxazole Trimethoprim Tetracyclines Chloramphenicol
ECSTaTIC about bacteriostatics
Bactericidal Drugs
Vancomycin Fluoroquinolones PCN Aminoglycosides Cephalosporins Metronidazole
Very Finely Proficient At Cell Murder
PCN
PCN G (IV), PCN V (oral)
Protoype beta-lactam abx
MOA: bind PCN-binding proteins (transpeptidases); block transpeptidase linking of cell wall; activate autolytic enzymes
Use: bactericidal for Gram + cocci/rods, Gram - cocci, and spirochetes
Toxicity: hypersensitivity, hemolytic anemia
Resistance: PCNase
Nafcillin, oxacillin, dicloxacillin
PCNase-resistant penicillins
Same MOA as PCN (bind PCN-binding protein, inhibit cell wall cross-linking, activate autolytic enzymes)
**Narrower spectrum: PCNase resistant b/c bulkier R group
Use: S.aureus, except MRSA, which has altered PCN binding protein target site (Naf for Staph)
Toxicity: Hypersensitivity
Methicillin: interstitial nephritis
Ampicillin, amoxicillin
Amniopenicillins
MOA: same as PCN.
**wider spectrum
PCN-ase sensitive: combine with clavulanic acid (PCNase inhibitor) to enhanve specturm
Use: Extended spectrum for PCN; H. influenza, E. coli, listeria monocytogenes, Proteus miribilis, Salmonella, enterococci
(HELPS kill Enterococci)
Toxicity: hypersensitivity, rash, pseudomembranous colitis
Ticarcillin
Carbenicillin
Piperacillin
Antipseudomonals
MOA: same as PCN (bind PCN-binding protein, inhibit cell wall cross-linking, activate autolytic enzymes)
Use: pseudomonas species and Gram - rods
**Susceptible to PCNase, use with clavulanic acid (beta-lactamase inhibitor)
Toxicity: hypersensitivity reactions
cephalosporins
1st generation
MOA: beta-lactam drugs that inhibit cell wall synthesis but are less susceptible to PCNase. BacteriCIDAL.
Cefazolin, cephalexin
Use: Gram+ cocci, Proteus mirabilis, E. coli, Klebsiella pneumoniae (PEcK)
Adverse: hypersentisitivity, cross hypersensitivity with PCN (5-10%)
nephrotoxicity of aminoglycosides
cefamandole: disulfram-like reaction with ethanol (methylthiotetrazole group)
cephalosporins
2nd generation
MOA: beta-lactam drugs that inhibit cell wall synthesis but are less susceptible to PCNase. BacteriCIDAL
Cefoxitin, cefaclor, cefuroxime
Use: Gram+ cocci, H. influenza, Enterobacter aeogenes, Neisseria spp, Proteus mirabilis, E. coli, Klebsiella pneumoniae, Serratia marcenscens
HEN PEcKS
cephalosporins
3rd generation
MOA: beta-lactam drugs that inhibit cell wall synthesis but are less susceptible to PCNase. BaceriCIDAL.
Ceftriaxone, cefotaxxime, ceftazidime
Use: Serious Gram- infections resistant to other beta-lactams; meningitis
cephalosporins
4th generation
MOA: beta-lactam drugs that inhibit cell wall synthesis but are less susceptible to PCNase. BacteriCIDAL.
Cefepime
Use: increased activity against pseudomonas and Gram+ organisms
Toxicity: Cross hypersensitivity with PCN
Aztreonam
Monobactam resistant to beta-lactamases
MOA: inhibits cell wall synthesis (binds to PBP3)
Synergistic with aminoglycosides
**No cross allergenicity with PCN
Use: Gram- rods (Klebsiella, Pseudomonas, Serratia)
No activity against Gram+ or anaerobes
**Best for PCN-allergic patients who cannot tolerate aminoglycosides (renal insufficiency)
Toxicity: usually nontoxic, occasional GI upset
Imipenem/cilastatin,
meropenem
MOA: Imipenem is a broad spectrum, beta-lactamase resistant carbapenem. Always administered with cilastatin to decrease inactivation in renal tubules
Use: Gram+ cocci, Gram- rods, anaerobes
Drug of choice for Enterobacter
Toxicity: Significant side effects limit use- GI, skin rash, CNS toxicity
Meropenem: lower risk of seizures, stable to renal tubules (does not require cilastatin)
Vancomycin
Inhibits cell wall mucopetpide formation by binding D-ala D-ala precursors. BacteriCIDAL. Resistance occurs with change to D-ala D-lac
Use: Serious, Gram+ multi-drug resistant organisms (S. aureus, C. difficile)
Toxicity: Nephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing (red man syndrome)
Well tolerated in general
Protein synthesis inhibitors
30S
Aminoglycosides
Tetracyclines
Protein synthesis inhibitors
50S
Chloramphenicol
Clindamycin
Erythromycin
Linezolid
Aminoglycosides
Gentamycin, Neomycin, Amikacin, Toramycin, Streptomycin
MOA: Inhibit formation of initiation complex, causing misreading of mRNA
**Requires O2 for uptake, thus no use against anaerobes
Use: Severe Gram - rod infections
***Synergistic with beta-lactam abx
Neomycin: bowel surgery
Toxicity: Nephrotoxicity (esp with cephalosporins)
Ototoxicity (esp with loop diuretics, TERATOGEN
Tetracyclines
MOA
Tetracycline, Doxycycline, demeclocycline, minocycline
MOA: Bacteriostatic; bind 30S and prevent attachment of aminoacyl-tRNA
- *limited CNS penetration
- *Do not take with milk, antacids, or iron containing preparations
Doxycycline: fecal elimination (good for pts with renal failure)
Demeclocycline: ADH antagonist; acts as diuretic in SIADH
Tetracyclines
Use/Toxicity
Use: Vibrio cholera, acne, chlamydia, ureaplasma, urealyticum, mycoplasma pneumoniae, tularemia, H. pylori, Borrelia burgdorferi, Rickettsia
(VACUUM THe BedRoom)
Toxicity: GI distress, discoloration of teeth and inhibition of bone growth in children, photosensitivity
**Contraindicated <8 years
Macrolides
Erythromycin, Azithromycin, Clarithromycin
MOA: Inhibit protein synthesis by irreversibly blocking translocation; bind the 23S rRNA of the 50S subunit
USE: URI, PNA, STDs (Gram + cocci)
Strep infection in pts allergic to PCN
Mycoplasma, Legionella, Chlamydia, Neisseria
Toxicity: GI discomfort, acute cholestatic hepatitis, eosinophilia, skin rashes
CYP inhibitor
Chloramphenicol
Inhibits 50S peptidyltransferase activity (inhibits creation of peptide bonds)
Use: Meningitis (H. influenzae, Neisseria meningitidis, Strep pneumoniae)
Toxicity: conservative use due to toxicity
Anemia (dose dependent), aplastic anemia (dose independent), gray baby syndrome (preemies b/c they lack liver UDP glucuronyl transferase)
Clindamycin
Blocks peptide bond formation at 50S ribosomal subunit.
Bacteriostatic
Use: anaerobic infections (clostridium perfringerns, bacteriodes fragilis)
Toxicity: pseudomembranous colitis, fever, diarrhea
Sulfanomides
Sulfamethoxazole, sulfisoxazole, sulfadiazine
MOA: PABA antimetabolites that inhibit dihydropteroate synthetase (a step in creating folic acid, required for thymidine and purine synthesis)
Use: Gram +/-, Nocardia, Chlamydia, UTI
Toxicity: Hypersensitivity rxn, hemolysis if G6PD deficient, nephrotoxic (tubulointerstitial nephritis), photosensitivity, kernicterus in infants
**displace other drugs form albumin (warfarin, etc.)
Trimethoprim
Inhibits bacterial dihydrofolate reductase
Use: In combination with sulfonamides; synergistic block of folate synthesis
Recurrent UTI, Shigella, Salmonella, Pneumocystis jiroveci pneumonia
Toxicity: Megaloblastic anemia, leukopenia, granulocytopenia
Sulfa drugs causing hypersensitivity
Sulfonamides (antimicrobials) sulfasalazine sulfonylureas thiazide diuretics furosemide acetazolamide
