Abx III Flashcards
What are the abx that are clindamycins?
Clindamycin
What is the use of clindamycin?
Narrow spectrum (strep and staph) used in the treatment of soft tissue infections
What is the MOA of clindamycin?
Binds to 50s of the ribosomes and prevents the formation of initiation complex and translocation to the P site
What are the key adverse effects of clindamycin?
GI: n/v
What abx is highly associated with C.diff infections?
Clindmycin
What type of abx is chloramphenicol?
Protein synthesis inhibitor
What is the MOA of chloramphenicol?
binds to 50s subunit of the ribosome and present transpeptidation or peptidyl bond formation
What are the two adverse effects of chloramphenicol?
Suppression of RBC production
Gray baby syndrome: infants lack acid conjugation
What is gray baby syndrome, and what abx causes it?
The UDP-glucuronyl transferase enzyme system of infants, especially premature infants, is immature and incapable of metabolizing the excessive drug load.
Chloramphenicol level in blood is increased, at higher concentration chloramphenicol blocks electron transport in the liver, myocardium, and skeletal muscles
What type of abx is linezolid?
Protein synthesis inhibitor
What is the MOA of linezolid?
Inhibits protein synthesis by binding to the P site of the 50s ribosome and inhibiting the formation of the ribosomal tRNA complex (very first step in protein synthesis)
What is linezolid used to treat?
Usually gram positive, and resistance organisms
What are the three abx that are used for treating resistant organisms?
Vanco
Linezolid
Daptomycin
What is the key adverse effect of linezolid?
Myelosuppression
What is the protein synthesis abx that prevents that very first step in protein synthesis?
Linezolid
What is the one protein inhibiting abx that is not broad spectrum? Which organisms does this treat?
Clindamycin
Gram positive cocci (MRSA)
What are the three sulfonamides?
- Sulfadiazine
- Sulfamethoxazole
- Sulfamethizole
What is the MOA of sulfa drugs?
Structurally similar to PABA, a precursor for dihydrofolic acid. These compete with PABA for the enzyme dihydrofolate synthase
What are sulfa drugs used to treat?
Broad spectrum for both gram positive and negative, but not usually used alone.
UTIs
What are the three key adverse effect of sulfa drugs?
Skin hypersensitivity
Skin Photosensitivity
Steven-Johnson syndrome
What are sulfa drugs usually combined with? Why?
Trimethoprim and pyrimethamine
Have synergistic effects
What are the abx that are trimethoprim abx?
Trimethoprim
Pyrimethamine
What are trimethoprim used to treat?
Gram negative in UTIs
What is the MOA of trimethoprim?
Inhibit bacterial dihydrofolate reductase
What are the adverse effects of trimethoprim?
Myelosuppression
Megaloblastic anemia
Leukopenia
What is TMP-SMX?
Trimethoprim + sulfa drugs
What are the adverse effects of TMP-SMX?
Same as for each agent alone
What is the MOA of fluoroquinolones?
Disrupts the winding of DNA and the separation o DNA strands during transcription (topoisomerases and gyrases)
What are the two major fluoroquinolones?
Ciprofloxacin
Levofloxacin
What are fluoroquinolones used for?
UTI
RTI
gram + and gram _
Anthrax treatment = ?
Fluoroquinolones
What are the key adverse effects of fluoroquinolones?
n/v/d
QT prolongation
Tendonitis
What is the nutritional problem that can arise with fluoroquinolones?
Binds divalent Cations (e.g. Ca) preventing absorption
What type of abx will impair absorption of Ca?
Fluoroquinolones
What type of abx is cipro?
Fluoroquinolone
What are group 1 fluoroquinolones? What are significant about these?
Norfloxacin
Least active fluoroquinolone
What are group 2 fluoroquinolones? What bacteria are these useful for?
Cipro
Levo
Ofloxacin
Gram negative
What are group 3 fluoroquinolones? What bacteria are these useful for?
Gatifloxacin
Gemifloxacin
Moxifloxacin
Gram positive
What is the MOA of metronidazole?
Prodrug taken up by the organism that binds to DNA and disrupt function
What does metronidazole treat (2)?
Anaerobic bacteria and protozoa
Why can metronidazole only treat anaerobic bacteria?
ROS generation that would otherwise be degraded by aerobic activity
What are the adverse effects of metronidazole?
n/v/d
Disulfiram effect
What is the MOA of disulfiram? What is this used for?
Inhibits acetaldehyde dehydrogenase in the liver
Used to treat alcoholics to induce bad effects with drinking EtOH
What should you avoid when taking metronidazole?
EtOH
What is the MOA of daptomycin?
Binds to the membrane and causes depolarization of the membrane and ultimately is bactericidal
What is daptomycin used to treat?
gram positive organisms
Is daptomycin bactericidal or bacteriostatic?
Bactericidal
What is the key adverse effect of daptomycin?
Myopathy and rhabdomyolysis
What is daptomycin usually used to treat?
Complicated soft tissue infections
What is the MOA of polymyxin B?
binds to phospholipids in the cell membrane and disrupts structure (specifically LPS)
Why is polymyxin B useful for gram negative organisms?
Punches hole in LPS
What type of bacteria is polymyxin B used to treat?
Gram negative (specifically targets LPS)
What is the key adverse effect of polymyxin B?
Rare if administered orally
What are the three MOA of PCN/cephalosporin resistance?
- Expression of beta lactamase
- Alteration in PBP
- ALteration in porin function
What is the MOA of resistance against aminoglycosides?
Expression of enzymes that alter chemical structure of the drug
What are the two MOA of resistance against Macrolides?
- Transport of drug out of the cell
2. ALterations of dug binding to the 50s ribosome
What is the main MOA of resistance against tetracyclines?
Transport of drug out of cell
What are the three MOAs of resistance against sulfonamides?
- Less sensitive drug target
- Increased synthesis of PABA
- Scavenge folic acid
What are the two MOAs of fluoroquinolones?
- Less sensitive drug target
2. Transport of drug out of cell
What is the main MOA of resistance to chloramphenicol?
Expression of inactivating enzymes
