Cell Wall synthesis Inhibitors Flashcards
there are 2 category drugs for cell wall synthesis inhibitors…
- betalactams
- vancomycin
what are the betalactam drugs?
- Carbapenems
- Monobactum
- Cephalosporins
- Penicillin
how does penicillin work?
Bind to penicillin-binding proteins (PBP’s) and inactivates transpeptidase
- prevents the cross linking of peptidoglycan chains in the bacterial cell wall,
- leading to loss of cell rigidity and cell death.
how do all betalactam drugs work?
all inhibit transpeptidase and prevent cross linking of peptidoglycan chains in bacterial cell wall
how does Vancomycin work?
Binds to D-Ala-D-Ala terminal of peptidoglycan pentapeptide side chain, leading to inhibition of transglycosylation and prevents peptidoglycan chain elongation.
how can bacteria resist betalactam drugs?
name a bacteria capable of using each mechanism of resistance.
- Penicillinases (b-lactamases): Staph
- Alteration of penicillin-binding proteins: MRSA
- Reduced permeability in Gram-negative cell membrane: Pseudomonas
name the 2 penicillin drugs, 1 is penicillinase susceptible and the other is parenteral administration, both are narrow spectrum
penicillinase susceptible = penicillin G
parenteral = penicillin V
what are the penicillin drugs that are narrow spectrum and are penicillinase resistant?
Methicillin, Naficillin, Oxacillin, Cloxacillin, Dicloxacillin
What are the 2 penicillin drugs that are Broad Spectrum and penicillinase susceptible?
- Ampicillin
- Amoxicillin
what are the penicillin drugs that are extended spectrum and anti-pseudomonal?
Ticarcillin, Piperacillin, Azlocillin
what are the first generation cephalosporins?
Cephalexin, Cefazolin
what are the Second Generation cephalosporin drugs?
Cefoxitin, Cefotetan, Cefaclor, Cefamandole, Cefuroxime
what are the 3rd generation cephalosporin drugs?
Ceftriaxone, Cefotaxime, Ceftriaone (IM), Ceftazidime, Ceforperazone, Cefixime (Oral)
what are the fourth generation cephalosporins?
Cefipime (IV), Cefpirome
for what bacteria do you use Penicillin G or Penicillin V?
Streptococci, Pneumococci, Meningococci, Treponema pallidum (Syphilis)
for what bacteria do you use Methicillin, Naficillin, Oxacillin, Cloxacillin, Dicloxacillin?
Staph Aureus except in MRSA
for what bacteria do we use Ampicillin, Amoxicillin?
Listeria monocytogenes (Ampicillin),
H. pylori (Amoxicillin),
what drug is used for prophylaxis for endocarditis before major procedures like dental surgery, in patients with known valvular issues?
Amoxicillin
for what do you use Extended Spectrum penicillin?
gram neg rods and pseudomonas
what are 2 drugs that are penicillin G?
it is used for what?
procaine –> syphillis
Benzathine –> rheumatic fever prophylaxis
how can we augment the activity or widen the spectrum of Ampicillin and Amoxicillin?
name 2 combinations
by using them with a beta lactamase inhibitor like clavulanic acid or sulbactum
amoxicillin + clavulanic acid = Augmentin
Ampicillin + Sulbactum
extended spectrum or antipseudomonal penicillins can be used synergistically with what other drugs?
why?
give an example of these drugs being used together.
Aminoglycosides
aminoglycosides enter the cell and prevents protein synthesis; penetration into a gram negative bacteria is enhanced when used with penicillin, which will break down the cell wall allowing the aminoglycoside easier entry
Piperacillin + Gentamycin
Piperacillin + Tazobactum
which 2nd generation cephalosporin can enter the BBB?
cefuroxime
what side effects can occur with the penicillins?
Cross-sensitivity between:
- individual penicillins
- penicillin and cephalosporins
if a patient has an allergy towards penicillin or cephalosporin…what drug to you substitute it for?
macrolide or Aztreonam
What is a side effect that can occur with Methicillin?
What is a side effect that can occur with Ampicillin?
What is a side effect that can occur with Ampicillin?
Methicillin: interstitial nephritis
Ampicillin: maculopapular rash
Ampicillin: diarrhea, pseudomembranous enterocolits
if there is a superinfection with clostridium difficile, with what do you treat it ?
metrodinazole
what do you treat using 1st generation cephalosporins?
Proteus, E.coli, Klebsiella pneumonia,
which cephalosporin do you use for surgical prophylaxis?
first gen (Cefazolin)
what do you treat using second gen cephalosporins?
Haemophilus influenza, Enterobacter, Neisseria, Proteus, E. coli, Klebsiella pneumonia, Serratia
which 2nd gen cephalosporin do you use for influenza?
which 2nd gen cephalosporin do you use for bacteroides fragilis?
cefuroxime, cefaclor, cefamandole
cefoxitin, cefotetan
which 3rd gen cephalosporin do you use for bacterial meningitis?
which 3rd gen cephalosporin do you use for bacterial Pseudomonas?
which 3rd gen cephalosporin do you use for bacterial Gonorrhoea?
which 3rd gen cephalosporin do you use for bacterial S. typhi?
Cefotaxime, Ceftriaxone
Cefoperazone, Ceftazidime
Ceftriaxone (parenteral), Cefixime (oral)
Ceftriazone, Cefaperazone
what are side effects that happen by using cephalosporins?
- Cross-hypersensitivity between cephalosporins
- nephrotoxicity if given with aminoglycosides
- dusulfiram like reactions with ethanol with: Cefamandole, Cefoperazone & Cefotetan
- Vitamin K deficiency
if a patient comes in with a History of anaphylaxis when given penicillin, you should immediately think that you can’t give what other drug?
any cephalosporin.
all carbapenems have what type of resistance?
name all the carbapenems
penicillinase resistant
- Imipenem
- Meropenem
- Etrapenem
- Doripenem
for what do you use carbapenems?
use in severe life-threatening infections
also, bacteroides fragilis and clostridium
how do carbapenems work?
Imipenem is rapidly inactivated by renal dehydropeptidase I, combined with cilastatin (inhibitor of renal dehydropeptidase) to prevent hydrolysis by enzymes in the renal brush border.
what is the side effect seen with carbapenems?
Seizures, GI distress,
name the only Monobactam?
what is it used for?
what side effect is seen with this?
Aztreonam
Used in gram negative infections, especially in patients allergic to penicillins/cephalosporins
No hypersensitivity reaction between penicillins/cephalosporins and aztreonam
how does vancomycin work?
Binds to D-Ala-D-Ala terminal of the nascent peptidoglycan pentapeptide side chain, leading to inhibition of transglycosylation and prevents peptidoglycan chain elongation.
what is the mechanism of resistance for vancomycin?
Decreased affinity of vancomycin for the binding site due to the replacement of terminal D-Ala by D-Lactate.
for what do you use vancomycin?
MRSA, Enterococci, C. difficile
what is a side effects occur with vancomycin?
Red Man’s Syndrome: release of histamine (flushing, redness of face, hypotension). Seen in fast IV infusion. Prevented by pretreatment with antihistamines.
Nephrotoxicity, Ototoxicity: can become additive if used with aminoglycosides
