Clasficacion de antimicrobianos sabinston cirugia
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Transcript of Clasficacion de antimicrobianos sabinston cirugia
By Valentin Sosa MD
DRUG CLASS AND NAME
MECHANISM OF ACTION COMMENT HALF-LIFE TOXICITY
ANTIBACTERIAL SPECTRUM
Penicillins
Penicillin G β-Lactam mechanism: inhibits bacterial cell wall by binding to penicillin-binding proteins (PBPs). It inhibits the final transpeptidation step of peptidoglycan synthesis in the bacterial cell wall
Prototype. Hydrolyzed by all β-lactamases
Short Low, but rarely an allergic reaction may be life threatening
Streptococcal species except enterococci and penicillin-resistant pneumococci, Neisseria species except lactamase-producing gonococci
Antistaphylococcal
Methicillin β-Lactam mechanism. Also penicillinase resistant and acid stable
First antistaphylococcal drug
Short Interstitial nephritis Staphylococcal species (methicillin sensitive) and streptococcal species except enterococcus
Oxacillin Short Interstitial nephritis Narrow spectrum; generally used for staphylococcal infections only
Nafcillin Short Interstitial nephritis
“Easy” gram-negative
Ampicillin β-Lactam mechanism Hydrolyzed by all β-lactamases
Short Low; diarrhea and rash
Streptococcal species, including many enterococci, Neisseria species (non– lactamase producing), Haemophilus influenzae (non– lactamase producing), some Escherichia coli and Proteus mirabilis
Amoxicillin Medium
Expanded spectrum
Carbenicillin β-Lactam mechanism Hydrolyzed by all β-lactamases
Short High sodium load. Inhibition of platelet aggregation
Greatly expanded gram-negative spectrum while still active against streptococcal species, including enterococci. Moderate antianaerobe activity. May not be reliable as the sole agent for established gram-negative rod infections
Ticarcillin β-Lactam mechanism Same Short Same, but less activity against enterococci
Very advanced spectrum
Mezlocillin β-Lactam mechanism Hydrolyzed by all β-lactamases Same
Short Low Same as expanded-spectrum penicillins but with more activity against Pseudomonas, Acinetobacter, and Serratia species
Piperacillin Short Low
β-Lactamase inhibitor combination
β-Lactam mechanism, plus
Low; same as constituent β-lactam
Clavulanic acid plus Clavulanic acid mechanism: β-lactamase inhibitor that increases the antibacterial activity of β-lactam antibiotics
Ticarcillin Short Same as ticarcillin or amoxicillin plus staphylococci (methicillin sensitive), lactamase-positive H. influenzae and some lactamase-producing gram-negative rods, and anaerobes
Cephalosporins
“First” generation β-Lactam mechanism Streptococcal species except enterococci, staphylococcal species (methicillin sensitive), and “easy” gram-negative rods
Short half-life
Cephalothin Prototype of class Short Low
Cephapirin Short Low
Longer half-life
Cefazolin Medium Low
“Second” generation β-Lactam mechanism Same as first-generation cephalosporins with expanded gram-negative activity not including Pseudomonas, Acinetobacter, or Serratia
Poor anaerobic activity
Shorter half-life
Cefamandole Short Low
Cefuroxime Medium Low
Longer half-life
Ceforanide Reduced antistaphylococcal activity
Long
Cefonicid Long
Good anaerobic activity
Same as above, plus many anaerobes
Short half-life
Cefoxitin Short Low
Longer half-life
Cefmetazole Medium Low
Cefotetan Long Prolonged prothrombin times
“Third” generation β-Lactam mechanism
Very active against most gram-negative rods except Pseudomonas, Acinetobacter, and Serratia. Poor against anaerobes. Less activity against streptococcal and staphylococcal species than first-and second-generation cephalosporins.
Poor Pseudomonas activity
Short half-life
Cefotaxime Short Low
Ceftizoxime Medium Low
Long half-life
Ceftriaxone Long Low
Good Pseudomonas activity
Cefoperazone Medium Low Same as above plus activity against many Pseudomonas, Acinetobacter, and Serratia species
Ceftazidime Medium Low
Cefepime Medium Low Same as above with increased activity against gram-positive cocci
Monobactams
Aztreonam β-Lactam mechanism: preference to PBP-3 of gram-negative bacteria. Very stable against β-lactamases
Safe for most patients with penicillin allergy
Short Low Excellent activity against most gram-negatives, including Pseudomonas and Serratia. Inactive against gram-positive cocci, anaerobes, and most Acinetobacter strains
Carbapenems β-Lactam mechanism, plus
Imipenem/cilastatin Cilastatin mechanism: inactivates dehydropeptidases, which would normally break the β-lactam ring of imipenem in the proximal tubule
Provided in combination with cilastatin to prevent renal breakdown and renal toxicity
Short Low. Seizures in certain high-risk patients
Extremely broad gram-positive and gram-negative aerobic and anaerobic. Modest activity against enterococci. Inactive against Stenotrophomonas (formerly Xanthomonas) maltophilia
Meropenem Provided alone without cilastatin
Short Reduced potential for seizures
Same activity as imipenem
Quinolones
Poor anaerobic activity
Inhibit bacterial enzyme DNA-gyrase, thus inhibiting DNA replication
Norfloxacin Oral only; urine levels only
Long Low Very broad Gram-negative activity. Gram-positive and very broad gram-negative activity, including Pseudomonas, Acinetobacter, and Serratia. Poor activity against anaerobes
Interaction leads to accumulation of theophylline
Ciprofloxacin Oral and intravenous (applies to all below)
Long
Ofloxacin Racemic mixture of levofloxacin (active) and dextrofloxacin (inactive)
Long
Levofloxacin Long
Aminoglycosides Bind to a specific protein in the 30S subunit of the bacterial ribosome, which leads to faulty alignment or recognition by RNA during initiation of microbial peptide chain formation
All have a low ratio of therapeutic-to-toxic levels. All are frequently underdosed. All exhibit a significant postantibiotic effect[*]
Medium Nephrotoxicity and nerve VIII toxicity, both auditory and vestibular
Extremely broad coverage of gram-negative rods. Poor activity against streptococci. Some synergism with penicillin or vancomycin against enterococci. No activity against anaerobes
Gentamicin See above Medium See above Most active against enterococci and Serratia spp.
Tobramycin See above Medium Statistically but questionably clinically significant decrease in nephrotoxicity
More active against Pseudomonas spp.
Amikacin See above Medium See above (aminoglycosides)
Active against a significant number of gentamicin- and tobramycin-resistant organisms
Netilmicin See above Medium See above (aminoglycosides)
See above (aminoglycosides)
Vancomycin Inhibits cell wall synthesis by binding to carboxyl subunits on peptide subunits containing free D-alanyl-D-alanine (different site from β-lactams—no cross resistance), plus may affect permeability of membrane, plus may inhibit RNA synthesis
Only IV. No oral absorption
Very long Hypotension and histamine release phenomena (redman syndrome) during infusion.
Streptococcal species, including many enterococci, staphylococci (including methicillin-resistant strains), Clostridium species. No activity against gram-negative rods
Streptogramins
Quinupristin/dalfopristin
Binds to different sites on the 50S subunit of bacterial ribosomes A 5- to 10-fold decrease in the dissociation constant of quinupristin is seen in the presence of dalfopristin
Significant postantibiotic effect[*]
Medium Reversible transaminase elevations
Most gram-positive pathogens, including vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, and penicillin-resistant Streptococcus pneumoniae but not Enterococcus faecalis
Oxazolidinones
Linezolid Attaches to the 50S subunit of the bacterial ribosome and inhibits protein synthesis
Oral or IV Long Reversible monoamine oxidase inhibition with the potential to interact with adrenergic or serotoninergic drugs and cause hypertension
Most gram-positive bacteria, including methicillin-resistant S. aureus and vancomycin-resistant enterococci
Macrolides
Erythromycin Attaches to the 50S subunit of the bacterial ribosome and may interfere with translocation reactions of the peptide chains
Oral or IV Medium Cholestasis with estolate (IV) form
Most gram-positive, Neisseria, Campylobacter, Mycoplasma, Chlamydia, Rickettsia, Legionella
Tetracyclines
Tetracycline Inhibit protein synthesis by attaching to the 30S subunit of the bacterial ribosome
Oral or IV Long Stain teeth of children
Many gram-positive, easy gram-negative rods, some anaerobes, Rickettsia, Chlamydia, Mycoplasma
Doxycycline Oral or IV Very long Same
Antifungal Triazoles
Fluconazole Inhibition of cytochrome P-450–dependent ergosterol synthesis
Oral or IV Very long Elevation of liver function test result
Most fungi except Candida krusei, Candida glabrata
Voriconazole Long Visual disturbances, fever
Most fungi