Antibiotics Flashcards
First generation cephalosporins are active against:
gram positive cocci
How does vancomycin work?
Inhibits transpeptidases
What are the three types of beta lactam drugs?
- Penicillins
- cephalosporins
- carbapenems (structurally different)
Which drugs block the 30S ribosomal unit?
Aminoglycosides and tetracyclines
Which drugs block the 50S subunit?
chloramphenicol, erythromycin, clindamycin, linezolid
How does the mechanism of action differ between aminoglycosides and tetracyclines?
Aminoglycosides bind directly to the 30S subunit. Tetracyclins block the binding of aminoacyl t-RNA
How does chloramphenicol work? What is a side effect?
Blocks peptidyl transferase, preventing protein synthesis–bacteriostatic. Can cause bone marrow suppression
How does erythromycin work?
Blocks the release of t-RNA
Which drugs are in the macrolide family?
azithromycin, clarithromycin, and erythromycin
How does clindamycin work?
Biinds to the same site as erythromycin to block release of the tRNA.
What is a serious side effect of clindamycin?
Predisposes patients to C difficile
Mechanism of action of sulfonamides and trimethoprim
Inhibition of nucleotide synthesis by blocking dihydrofolate reductase
Mechanism of action of quinolone
Inhibits DNA synthesis by blocking DNA gyrase
Mechanism of action for rifampin
Inhibits RNA synthesis by blocking the RNA polymerase
When is vancomycin used?
As a last resort against MRSA
Aminoglycosides=bacteriocidal or static?
Bactericidal. Mechanism of action not fully known, though thought to interfere with protein synthesis and cell wall integrity
Tetracycline=bactericidal or static?
static
chloramphenicol=bactericidal or static?
Both
Erythromycin=bactericidal or static?
static
Clindamycin=bactericidal or static?
static
Name several aminoglycosides
streptomycin
gentamicin
Neomycin
How do aminoglycosides work?
inhibition of initiation complex and misreading of messenger RNA
Aminopenicillins treat:
gram positive enterococcus and gram negative bacteria
Which two antibiotics are administered together to provide broad gram negative coverage?
ampicillin and gentamicin
Name the penicillinase resistant antibiotics:
methicillin, Nafcillin, Oxacillin (I MET a NAsty Ox)
Which penicillins can be used to treat pseudomonas?
ticarcillin and carbenicillin (carboxypenicillins)
Mezlocillin and peperacillin (ureidopenicillins)
What do beta-lactamase inhibitors do? Name them.
Beta lactamase inhibitors prevent beta lactamase from degrading the antibiotic, protecting them.
Clavulonic acid, sulbactam, and tazobactam
What advantage do cephalosporins have over penicillins?
Resistance to beta lactamases and can be used on penicillin resistant bacteria
What bacteria remain resistant to cephalosporins?
MRSA and enterocci
Which cephalosporins are effective against pseudomonas?
ceftazidime, cefoperazone, cefepime (TAZ, FOP, FEP)
Which antibiotics can kill MRSA?
Vancomycin
What is imipenem NOT able to kill?
MRSA, pseudomonas, mycoplasma
What do you need to coadminster imipenem with?
cilastin. This is to protect renal degradation of the antibiotic.
What does aztreonam kill?
Gram negative aerobic bacteria (including pseudomonas)
Which antibiotics inhibit the 50S subunits?
clindamycin, chloramphenicol, erythromycin, and linezolid
Which antibiotics inhibit the 30S subunit?
Tetracycline and aminoglycosides
What does chloramphenicol kill?
Gram positive, gram negative and anaerobic bacteria. Very effective
What are the side effects of chloramphenicol?
aplastic anemia and gray baby syndrome
What do you use clindamycin for?
anaerobic interactions, gram + bacteria
What is the issue with administering clindamycin?
C difficile interactions
What would you treat C difficile with?
Vancomycin
Erythromycin treats:
Gram positive organisms
What are the side effects of erythromycin?
GI discomfort, rare hepatitis. Overall, a very good safety profile
Aminoglycosides kill:
gram negative including pseudomonas
What are the side effects of aminoglycosides?
renal toxicity, vertico, hearing loss
What is a side effect of tetracycline?
discolored teeth
What is the mechanism of action for fluoroquinones?
DNA gyrase
What antibiotic covers all gram negative bugs?
Aztrenam
How does vancomycin work?
Also attacks the cell wall, but by complexing with D alanine-Dalanine
How is vancomycin administered?
Through IV
What can you use to treat a systemic fungal infection?
amphotericin
What is the problem with amphotericin?
Severe side effects including renal toxicity, severe anemia
