From Jen: Antimicrobials Flashcards
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
