Antibiotics Flashcards
Pen G and Pen V:
Route of admin
MOA
Pen G- IV and IM
Pen V- oral
D-ala D-ala analog.
Binds PBP to block transpeptidase cross-linking of peptidoglycan in cell wall. Activate autolytic enzymes.
Clinical use for PenG/PenV (5)
Bactericidal or Bacteriostatic?
Penicillinase Sensitivity?
- S. pneumo
- S. pyogenes
- Actinomyces
- N. meningitidis
- T.pallidum
Bactericidal
Penicillinase sensitive
PenG/PenV
Adverse (2)
Mech of Resistance
- Hypersensitivity (Rash/anaphylaxis)–>Type1 Hypersens
- direct Coombs hemolytic anemia (Haptan)–>Type2 Hypersens
Resistance: Penicillinase in bacteria (B-lactamase) cleaves B-lactam ring between N and C=O
Name 2 penicillinase sensitive penicillins
Aminopenicillins
- Amoxicillin
- Ampicillin
Aminopenicillins (Amoxicillin/Ampicillin)
MOA
MOResistance
Penicillinase Sensitivity?
MOA:
Same as penicillin w/ wider spectrum
Penicilinas (B-lactamase) cleaves B-lactam ring
Penicillinase sensitive–>combine w/ clavulanic acid to protect against destruction by B-lactamase
Typically: Amox w/ sulbactam, Amp w/ clavulanic acid
Aminopenicillins: Clinical Use (8*)
Broad Spectrum "Ampicillin/Amoxicillin HHELPSS kill Enterococci" H.flu H.pylori E.coli Listeria Proteus Salmonella Shigella Enterococci
Aminopenicillins (Amoxicillin/Ampicillin):
Adverse (3)
- Hypersensitivity
- Rash–>not a hypersensitivity (not IgE) but specific for amoxicillin with mononucleosis
- pseudomemb colitis
What contributes to Penicillin’s clinical use
The R group on penicillins determines
- Broad vs. Narrow
- ability of drug to cross Bacterial membrane
Name Penicillinase-resistant penicillins (4)
Why “resistant”?
- Dicloxacillin
- Nafcillin
- Oxacillin
- Methicillin
Bulky -R group blocks B-lactamase’s access to B-lactam ring
Name Penicillinase-resistant penicillins: Clinical Use(1*)
Narrow spectrum
1. S. aureus (Except MRSA-it mutates transpeptidase enzyme gene so drug can’t bind))
“use Naf for Staph”
Name Penicillinase-resistant penicillins:
Adverse (2)
- Hypersensitivity (Rash/anaphylaxis)
2. Interstitial Nephritis (remember Methicillin was taken off market for beating up too many kidneys)
Name Antipseudomonal penicillins (2)
Penicillinase Sensitivity?
- Pipercillin
- Ticarcillin
Penicillinase sensitivity–>use B-lactamase inhibitors
*classically Tazobactam w/ Pipercillin/Ticarcillin
Antipseudomonal penicillins: Clinical Use (2) Adverse (1)
- Pseudo spp.
- Gram (-) rods
* typically with Tazobactam - Hypersensitivity
Why use B-lactamase inhibs?
Name 3* B-lactamase inhibs
Added to penicillin abx to protect abx from penicillinase destruction
“CAST a net to protect Penicillins”
- Clavulanic Acid (w/ Amox)
- Sulbactam (w/ Amp)
- Tazobactam (w/ Pip or Ticar)
Cephalosporins: MOA Bactericidal or Bacteriostatic? Penicillinase Sensitivity? MOResistance
- B-lactam drugs inhib cell wall synthesis
- Bactericidal
- Less susceptible to penicillinase
- Structural change in PBP (transpeptidase)
Cephalosporins:
Organisms typically not covered by 1st-4th generation
“1st-4th Generation cephalosporins are LAME”
- Listeria
- Atypicals (chlamydia/mycoplasma)
- MRSA (covered by ceftaroline-5th gen)
- Enterococci
1st Gen Cephalosporins:
Names (2)
coverage (5)
Any special uses
- Cefazolin-used pre surgery to prevent S.aureus infection
- cephalexin
“PEcK-g”
- gram + cocci
- Proteus
- E.coli
- Klebsiella
2nd Gen Cephalosporins:
Names (3)
Coverage (8)
“FAke FOX FUR”
- CeFOXitin
- CeFAclor
- CeFURoxime
“PEcK-g HENS”
- gram + cocci
- Proteus
- E.coli
- Klebsiella
- H. flu
- Enterobacter aerogenes
- Neisseria
- Serratia marcescens
3rd Gen Cephalosporins:
Names (3)
Coverage (3,1)
Serious gram (-) infections resistant to other B-lactams
- Ceftriaxone- 1. N.meningitids 2. N.gonorrhea 3. Lyme
- Cefotaxime
- Ceftazidine- 1. Pseudo
4th Gen Cephalosporins:
Names (1)
Coverage (3)
Cefepime
- Gram (+)
- Gram (-)
- Pseudo
5th Gen Cephalosporins:
Names (1)
Coverage (3)
Ceftaroline
- Gram (+)
- Gram (-)
- MRSA
Name 2 Cephalosporins that cover Psuedomonas
- Ceftaz (3rd gen)
2. Cefepime (4th gen)
Cephasporins:
Adverse (6)
- Hypersensitivity
- Autoimmune Hemolytic anemia
- Disulfuram-like Rxn
- Vit K def (from killing off enteric bacteria)
- Cross-react w/ penicillins
- Nephrotox w/ Aminoglycosides
Name Carbapenems (4)
Special considerations per drug
- Imipenem
- Meropenem- less Seizure Risk, stable to Dehydropeptidase I
- Ertapenem-new, limited Pseudomonas coverage
- Doripenem-new
Carbapenems:
MOA
Special administration*?
Broad or Narrow
MOA: B-lactamase resistant
- Always admin w/ CILASTATIN (inhib Renal Dehydropeptidase I) to decrease inactivation of drug in Renal tubules
- Broad spectrum
“With imipenem, the kill is LASTIN’ with CILASTATIN”
Carbapenems:
Coverage(3)
When used?
- Gram + cocci
- Gram - rods
- anaerobes
- Wide spectrum but limited use to life-threatening infections or after other drugs fail b/c of significant Adverse
Carbapenems:
Adverse (3)
- Seizures/ CNS tox @ high plasma levels
- GI distress
- Skin rash
Aztreonam (a Monobactam):
MOA
Penicillinase sensitivity
Adverse
Prevents Peptidoglycan cross-linking by binding to PBP-3
- Less susceptible to B-lactamases
- usually non-toxic, occasional GI upset
Aztreonam:
Coverage (1)
3 special uses
Gram - rods
- Penicillin-allergic patients safe
- well-tolerated in renal insuff pt (who can’t use Aminoglycosides)
- Synergistic activity w/ amino glycosides
Vancomycin:
MOA
Penicillinase Sensitivity
Bactericidal or Bacteriostatic
- binds Dala Dala portion of cell wall precursors to prevent peptidoglycan formation
- Not sensitive to penicillinase
- Bactericidal against most (Bacteriostatic for C.Diff)
- bacterial A.A. mutation to Dala Dlac
“Pay back 2Dala’s (dollars) for VANdalizing”
Vancomycin:
Adverse(4)
“Vancomycin is generally well tolerated but NOT trouble free”
- Nephrotox
- Ototox
- Thrombophlebitis
- Red Man Syndrome- pretreat w/ histamines & slow infusion
Bacterial Ribosome subunits
70S (30S, 50S)
Which Abx bind 30S and which bind 50S?
Bactericidal or Bacteriostatic
” Buy AT 30, CCEL (sell) at 50”
30S:
- Aminoglycosides- bactericidal
- Tetracyclines-bacteriostatic
50S:
- Chloramphenicol-bacteriostatic
- Clindamycin-bacteriostatic
- Erythromycin (macrolides)-bacteriostatic
- Linezolid-variable
Name Aminoglycosides (5)*
“MEAN (a-min-oglycoside) GNATS caNNOT kill ANAEROBES.”
- Gentamicin
- Neomycin
- Amikacin
- Tobramycin
- Streptomycin
Aminoglycosides:
MOA(2)*
Special consideration about MOA*
“‘A’ starts the alphabet, ‘A’minoglycosides inhib INITIATION”
- Irreversible inhib initiation–>mRNA misread
- inhib translocation
Require O2 for uptake making them ineffective against anaerobes
“‘Mean’ GNATS caNNOT kill ANAEROBES”
Aminoglycosides: Clinical use (4)
1 . Severe Gram - rod (like Pseudo/E.coli)
- Synergistic w/ B-lactams–> increase response
- Bowel surgery (Neomycin)
- Neonate suspected infections (Gentamycin & Ampicillin)