Antibiotics Flashcards
What are the beta lactam classes?
Penicillins
Cephalosporins
Carbapenems
Monobactams
What is the beta lactam MOA?
Beta lactam ring binds to transpeptidase which inhibits bacterial wall synthesis. They can also bind to transpeptidase and cause bacterial autolytic enzymes to be relases and cause cell lysis.
How do bacteria fight against beta lactams?
Beta lactamases
Reduce binding affinity to transpeptidase/PBP
Over production of PBP
Loss of membrane porins
Expression of efflux pumps
What bacteria can natural penicillins be used against?
Gram + (s pneumoniae, staph, b anthrax, anaerobes)
Gram - (n meningitides)
Spirochetes (treponema pallidum/syphylis)
NO MRSA
What is natural penicillin a first line treatment for?
Strep Throat -GABHS
Syphilis
Cellulitis
Meningitis
What are the natural penicillins?
PCN G
PCN V
What are the antistaphylococcal PCNs?
Dicloxacillin
Nafcillin
Oxacillin
When can antistaphylococcal PCNs be used?
Only skin and soft tissue infections
s aureus and s epidermis
NO MRSA coverage
What are the aminopenicillins?
Amoxicillin and ampicillin
What are first line uses for aminopenicillins?
Otitis media (amoxicillin)
Endocarditis prophylaxis
What are the most common causes of otitis media?
S pneumoniae
M catarrhailis
H influenza
What are the advantages of an aminopenicillin over a natural penicillin?
Better oral absorption, longer half life, better gram negative penetration
What are the PCN/Beta lactamase inhibitor drugs?
Amoxicillin/Clavulanic acid (amoxicillin)
Ampicillin/sulbactam (Unasyn)
What does the addition of the BLI do to the susceptibility profile of a PCN/BLI?
Better staph coverage
Overcomes BL resistance
Extends spectrum of activity
What are the first line uses for PCN/BLI?
Sinusitis, PNA, COPD exacerbations
S pneumo, H flu, S aureus
Why not just use a PCN/BLI on everyone?
Increased cost
more GI effects
More severe/refractory infections only
What are the extended spectrum penicillins/antipseudomonal penicillins?
Piperacillin/tazobactam (Zosyn)
What does the extended spectrum penicillins cover that other PCNs do not?
Pseudomonas and proteus
When do you chose a extended spectrum penicillin?
UTI
Peritonitis
Skin/soft tissue
Lower respiratory tract
Septicemia
What is the mechanism of action for cephalosporins?
Beta lactam ring binds to transpeptidase which inhibits bacterial wall synthesis. They can also bind to transpeptidase and cause bacterial autolytic enzymes to be released and cause cell lysis.
What is the difference between cephalosporin generations?
Increasing generations increases Gram - coverage at the cost of gram + coverage
What are the 1st generation cephalosporins?
cephalexin (Keflex)
cefazolin (Ancef)
cefadroxil (Duricef, Ultracef
What bacteria do you use Keflex against?
Staph, strep, E coli
What are common indications for Keflex?
Skin infections
Impetigo
Pharyngitis/otitis media
Cystitis (esp pregnancy)
What are common indications for Ancef (cefazolin)?
Surgical prophylaxis
Serious MSSA infections (endocarditis, PNA, UTI)
(cause IM/IV only)
What are common indications for cefadroxil (Duricef, Ultracef)
Pharyngitis/tonsillitis
Advantage is that it is taken BID
What are the 2nd generation cephalosporins?
Cefuroxime
Cefoxitin
Cefotetan
Cefaclor
Cefprozil
What are the indications for cefoxitin/cefotetan?
surgical prophylaxis for dirty procedures
What are the indications for cefuroxime/cefaclor/cefprozil?
2nd line for pharyngitis, sinusitis, OM, upper and lower respiratory tract infections
What are the 3rd generation cephalosporins?
Ceftriaxone (Rocephin)
Cefdinir (Omnicef)
Cefixime (Suprax)
What are the indications for ceftriaxone (Rocephin)?
1st line for Neisseria gonorrhoeae
Good for pneumococcals
Open abdominal prophylaxis
Meningitis
PID
What are the indications for cefdinir (Omnicef) and Cefixime (Suprax)?
2nd line for upper and lower respiratory infections
Skin and soft tissue infections
What is the 4th generation cephalosporin?
Cefepime (Macipime)
What is the spectrum of cefepime?
Gram +, gram -, and pseudomonas
When do you use cefepime?
Severe infections
Meningitis (bc penetrates CSF)
SAVE THIS DRUG
What is the 5th generation cephalosporin?
Cetaroline
What is the spectrum of coverage for ceftaroline?
Gram +
MRSA
VRE
Which generations of cephalosporins penetrate the CNS?
3 and 4 do well
5 does a little
What is the monobactam?
Aztreonam (Azactam)
What generation cephalosporin are monobactams closest to?
3rd/4th generation
What is the susceptibility of aztreonam?
Gram -
Pseudomonas
No gram + or anaerobes
When do you use aztreonam?
Severe UTIs (E coli)
Bacteremia/Sepsis
Inhalation (for CF respiratory infections)
What are the carbapenems?
Imipenem/cilastatin
Meropenem
Ertapenem
Doripenem
What is the susceptibility of carbapenems?
Very broad spectrum
Gram +
Gram -
Anaerobes
Pseudomonas
NO MRSA
When to use a carbapenem?
Severe infections only
UTI
Meningitis
Peritonitis/intra abd infections
Resistant wounds (chronic diabetic)
Osteomylitis
What are the common side effects of beta lactams?
GI (N/V/D)
Vaginal candidiasis
What are adverse events for beta lactams?
Hypersensitivity
C dif
Nephritis
Anemia, thrombocytopenia
CNS toxicity
How many people claim to be allergic to PCNs? How many are actually allergic?
10%, <1%
How are beta lactams metabolized? Excreted?
hepatic metabolism and renal secretion
What monitoring should you do for beta lactams?
CBC with prolonged treatment for neutopenia
Kidney function for prolonged treatment
What pregnancy category are beta lactams?
B
What are the drug interactions of beta-lactams?
Decrease the effectiveness of oral contraceptives
What drug is a glycopeptide?
Vancomycin