Cell Wall Inhibitors (Antibiotic I) Flashcards Preview

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Flashcards in Cell Wall Inhibitors (Antibiotic I) Deck (43):

What are the major ABX that function via inhibition of cell wall synthesis?

  • Beta-lactams (Penicillins and Cephalosporins)
  • Vancomycin 
  • Daptomycin 
  • Bacitracin


How do Penicillins function with respect to bacteria?

Bactericidal (Works best in rapidly proliferating organisms WITH cell wall)

Bind to Penicillin-Binding Proteins (PBPs) and inhibit transpeptidase (cross-linking of peptidoglycans → osmotically unstable membrane will rupture)


What are the three mechanisms of resistance in Penicillins

  1. Inactivation by beta-lactamases (most common)
  2. Modification of PBP target
  3. Impaired penetration of drug to target PBP


What are the different sub-classifications of Penicillins?

  • Natural Penicillins
  • Aminopenicillins
  • Penicillinase-Resistant Penicillins
  • Antipseudonomal Penicillins


What are beta-lactamase inhibitors

Considered "suicide inhibitors" → potent, irreversible inhibitors of most lactamase (extends the spectrum of ABX)


What ABX are considered Natural Penicillins? How is each PCN administered (if applicable)? [2]

  • Penicillin V (PO)
  • Penicillin G (IV, IM, Depot)


What ABX are considered Aminopenicillins? How is each PCN administered (if applicable)? [2]

  • Amoxicillin (PO)
  • Ampicillin (PO, IV)


What ABX are considered Penicillinase-Resistant Penicillins? How is each PCN administered (if applicable)? [5]

  • Nafcillin (PO, IV)
  • Oxacillin
  • Dicloxacillin
  • Methicillin (No longer available in the US)
  • Cloxacillin (No longer available in the US)


What ABX are considered Antipseudomonal Penicillins?How is each PCN administered (if applicable)? [3]

  • Piperacillin (IV)
  • Ticarcillin (IV)
  • Carbenicillin (IV)


What ABX are considered Beta-lactamase inhibitors? What PCN are each inhibitor used with (if applicable)? [3]

  • Clavulanic acid (Adjunct TX: Amoxicillin, Ticarcillin)
  • Sulbactam (Adjunct TX: Ampicillin)
  • Tazobactam (Adjunct TX: Piperacillin)


What are MOAs and General Target of Natural Penicillins?

  • Narrow spectrum 
  • Acid labile (PCN-G)
  • Penicillinase sensitive


  • Gram-positive cocci (Does not include Staphylococcus)
  • Obligate anaerobes
  • Some gram-negative (E. coli, H. influenzae, N. gonorrhoeae, Trepnema pallidium and suseptible Pseudomona spp.)


What are Natural Penicillins used to TX/Prophylaxis?

  • Upper/Lower Respiratory Tract Infections
  • Throat infection
  • Skin infection
  • GU tract infection


  • PROPHYLAXIS Rheumatic fever, dental procedure (for those at risk of endocarditis, gonorrhoeae, syphilis exposure)


What are MOAs and Specific Target/Bacteria of Aminopenicillins?

PCN-G MOA + improved coverage of gram-negative cocci and Enterobacteriaceae


What are Aminopenicillins used to TX/Prophylaxis?

  • URI (sinusitis, otitis)
  • UTI (uncomplicated)
  • Meningitis
  • Salmonella infections (Not 1ST LINE)


No mentioned prophylactic measures


What are the MOAs and General Targets of Penicillinase-Resistant Penicillins?

  • Also called "Antistaphylococcal Penicillins"
  • Penicillinase resistant, narrow spectrum
  • General Target: staphylococcal infections with high beta-lactamase production
    • Not active against gram-negative or anaerobes



What is the name for Staphylococci spp. that are resistant to penicillinase-resistant penicillins? 

MRSA (Methicillin Resistant Staphylococcus aureus)


What are Penicillinase-resistant penicillins used to TX/prophylaxis?

  • Cellulitis 
  • Endocarditis


What are MOAs and Specific Target/Bacteria of Antipseudomonal penicillins?

  • PCN-G MOA + greater gram negative coverage (including Pseudomonas spp.)
  • Coverage: H. influenzae, Klebsiella sp. 
  • No coverage: Treponema palladium, Actinomyces spp. 


What are the PK characteristics (Absorption, Distribution, Elimination) of Penicillins?

Absorption: Poor oral administration (food DEC absorption), IV preferred 

Distribution: Widely distributed, poorly penetrate the eye, CNS (only when meninges are inflamed) and prostate

Elimination: Kidney unchanged (Antipseudomonal and naficillin→billary excretion)


How does Probenecid interact with penicillins

Prevents active secretion of Penicillin into urine


What are important ADRs of Penicillins?

  • Hypersensitivity reaction (could lead to analphylasis, Serum sickness interstitual nephritis, hemolytic anemia)
  • GI effects (related to oral agents)
  • Diarrhea 
  • Vaginal candidiasis (2ndary)


What are some important Drug interactions of Penicillins?

Bacteriostatic agents (i.e. tetracycline, aminoglycosides): DO NOT give concurrently

Warfarin: metabolism affected by anti-pseudomonal PCN


What are Cephalosporins? 

  • Class of Beta-lactam drugs, chemically similar to PCN with respect to MOA and toxicity
    • possess dihydrothiazine ring → INC resistant to beta lactamases
  • Bactericidal 
  • Classified in 5 generations


What ABX are considered 1st Generation Cephalosporins? How are the ABX administered (if applicable)? [3]

  • Cefazolin (IV)
  • Cephalexin (PO)
  • Cefadroxil (PO)

Only class that has "ph" instead of "f" in name


What ABX are considered 2nd Generation Cephalosporins? What added coverages does each ABX have (Gram-negative vs. Anaerobic)? How are the ABX administered (if applicable)? 

  • Added Gram-negative coverage
    • Cefuroxime (IV, PO)
    • Cefaclor (IV, PO)
    • Cefporzil (IV, PO)
  • Added anaerobic coverage
    • Cefotetan (IV)
    • Cefoxitin (IV)


What are ABX are considered 3rd Generation Cephalosporins? How are ABX administered (if applicable)? [8]

  • Cefpodoxime (PO)
  • Cefdinir (PO)
  • Cefixime (PO)
  • Cefditoren (PO)
  • Cefibuten (PO)
  • Cefotaxime (IV, IM)
  • Ceftriaxone (IV, IM)
  • Ceftazidime (IV)


What are ABX are considered 4th Generation Cephalosporin? How are the ABX administered (if applicable)? [1]

  • Cefepime (IV, IM)


What are ABX are considered 5th Generation Cephalosporins? How are ABX administered (if applicable)? [2]

  • Ceftaroline fosamil (IV)
  • Ceftolozane (IV)


What are the three mechanisms of resistance with Cephalosporins

  • Mutation in PBP
  • Production of Beta-lactamases
  • Alteration in cell-membrane porins in gram-negative organ


What are the MOAs and General Target/Bacterias of 1st Generation Cephalosporins?

Similiar MOA to Penicillinase-Resistant (Anti-staph) PCN and Aminopenicillins

General Target:

  • Aerobic Gram-positive
  • Above diaphragm anaerobes
  • Community acquired Gram-negative


What are 1st Generation Cephalosporins used to TX/Prophylaxis

GRAM-POSITIVE (patients who can't take PCN)

  • Septic arthritis (adults)
  • Skin infections
  • Acute otitis media
  • Pharyngitis 
  • PROPHYLAXIS: Clean surgeries, UTI


How does 2nd Generation Cephalosporin compare to 1st Generation coverage?

Somewhat less Gram-positive coverage than 1st Gen, but significantly greater Gram-negative coverage


What is significant about the spectrum of 3rd Generation Cephalosporins

  • Expanded Gram-negative coverage
  • Penetration of BBB


What are extra-defining features Ceftriaxone, Cefotaxime, Ceftazidime? (3rd generation Cephalosporins)

Long Half-Life

  • Ceftriaxone (IV, IM)
  • Cefotaxime (IV, IM)

INC Anti-pseudomonal coverage

  • Ceftazidime (IV)



What are 3rd Generation Cephalosporins used to TX/Prophylaxis?

1st LINE TX:

  • Meningitis
  • Pneumonia (Children and Adults)
  • Sepsis
  • Peritonitis

Additional TX:

  • UTI
  • Skin infections
  • Osteomyelitis
  • Neisseria gonorrheae


What are MOAs and General Target/Bacterias of 4th Generation Cephalosporins?

Good activity against all gram bacteria including anaerobic coverage (P. aerugnosa, H. influenzae, N. Meningitidis, N. gonorrheae; Enterobacteriaceae resistant to other Cephalosporins)


What are 4th Generation Cephalosporins used to TX/Prophylaxis?

  • Intra-abdominal infections
  • Respiratory tract infections
  • Skin infections


What is important to know pertaining to 5th generation cephalosporins

  • Activity against MRSA
  • TX  complicated skin and intra-abdominal infections including CAP
  • Expensive (rarely used)


What are the PK characteristics (Absorption, Distribution, Elimination) of Cephalosporins

Absorption: PO rapidly absorbed, variable effects with food

Distribution: Extensive (2nd, 3rd, 4th Gen can cross BBB; think long half-life for 3rd Gen)

Elimination: Kidneys (most)


What are General ADRs/Drug interactions associated with Cephalosporins?

Hypersensitivity: Similar to PCN, allergic reaction (rare; S/Sx rash, fever, eosinophilia, hives)

Superinfection: Resistant organisms/fungi may proliferate

GI effects: N/V/D (well tolerated)

Blood Dyscrasias (will resolve w/ DC drug): Eosinophilia, Thrombocytopenia, Leukopenia


  • Probenecid (INC serum levels of co-administered Cephalosporin)
  • Warfarin (INC effects; Cefotetan, Cefazolin, Cefoxitin, Ceftriaxone)


What specific ADRs are associated with Ceftriaxone? (3rd Generation Cephalosporin)

  • Cholestasis
  • DRUG INTERACTION: INC effects of Warfarin


What specific ADRs are associated with Cefotetan? (2nd Generation Cephalosporin, added anaerobic coverage)

Methylthiotetrazole side chains induce disulfiram-like reaction with EtOH ingestion


What are Monobactams?