Beta Lactams 2 - Fitzpatrick Flashcards by Andrew Herrmann

1st generation Cephalosporins have high similarity to what Penicillins? So?

Main drugs? (2) Oral or Parenteral?

Ampicillin/Amoxicillin + beta-lactamase inhibitor combos
- can enter gram (-) pores OR grapple with gram (+) organisms AND deal with beta-lactamase producing enzymes

Cephalexin (ORAL), Cefazolin (PARENTERAL)

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1st generation Cephalosporins are good against what organisms?

Strep. pyogenes/pneumoniae and Staph. aureus (Penicillin-sensitive strains)

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Clinical use for EITHER 1st generation Cephalosporin

Surgical prophylaxis

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Good use of Cephalexin RATHER THAN Cefazolin

ORAL –> pharyngitis (good dosing schedule)

- Strep. pyogenes, etc.

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3rd generation Cephalosporins - thing what ADDITIONAL coverages besides those from 1st generation? (2)

CNS infections (meningitis)

- Pseudomonas

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3rd generation Cephalosporin drugs (4)

Ceftriaxone
Cefotaxime
Ceftazidime
Cefaperazone

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***Benefits of Ceftriaxone vs. a 1st generation (6)

Long 1/2 life
Penetrates CSF and bone
Treats NEISSERIA (gonorrhea and meningitis)
Treats Ampicillin-resistant H. Influenza
Treats BORRELIA (LYME DISEASE in CNS or joints)
Biliary clearance (easier dosage adjustments)

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***Benefit of Cefotaxime vs. a 1st generation

Useful for MENINGITIS due to…

H. influenza
S. pneumoniae
N. meningitidis
Enteric bacteria

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Benefit of Ceftazidime vs. a 1st generation

Pseudomonas coverage…

- Strains resistant to anti-pseudomonal Penicillins
- Penicillin allergy

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Benefit of Cefaperazone vs. 1st generation

Pseudomonas coverage

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Patient is on an antibiotic and develops a flushing reaction after drinking alcohol. What drug was she on?

Cefaperazone

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LIKE 1st GENERATION, 3rd generation is good against what organisms?

S. aureus
S. pneumoniae
S. pyogenes

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UNLIKE 1st GENERATION, 3rd generation ALSO is good against what organisms?

Gram (-) rods

- Enteric organisms

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ALL 3rd generation drugs are administered how?

Parenteral

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In SERIOUS Pseudomonas infection, Ceftazidime or Anti-Pseudomonal Penicillin should ALWAYS be administered with what else?

An aminoglycoside (Tobramycin)

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2nd generation Cephalosporin drugs (4) (+ administration route)

Cefoxitin - PARENTERAL
Cefotetan - PARENTERAL
Cefaclor - ORAL
Cefuroxime axetil - ORAL

2nd generation Cephalosporins are BEST vs. which 2 groups of organisms (compared to 1st generation)?

Gram (-) – E. coli, Klebsiella (aspiration), H. influenza, Moraxella cattharalis (nose), Proteus
Anaerobes (B. fragilis, C. diff., Actinomyces, etc.)

Clinical uses of 2nd generation Cephalosporin (2)

Intra-abdominal or gynecological sepsis

- Intra-abdominal/colorectal surgery

Best 2nd generation Cephalosporins for anaerobic bacteria

Cefoxitin, Cefotetan (i.e. the parenteral ones)

Best 2nd generation Cephalosporin for methicillin-resistant (beta-lactamase producing) organisms

Cefuroxime axetil

Child patient starts an antibiotic and develops a type 3 hypersensitivity (like serum sickness) reaction in her skin and joints. Drug used?

Cefaclor (2nd generation Cephalosporin)

4th generation Cephalosporin drug

Has actions comparable (a little better) to a combo of which other 2 generations?

Cefepime

1st generation (gram (+) w/ beta-lactimase insensitivity) + 3rd generation (gram (-), pseudomonas)

A patient had a Pseudomonas infection and was taking Ceftazidime, but the drug started to wear off. Other option?

Cefepime (4th gen.) - active against Ceftazidime-resistant strains of Pseudomonas

2 potential adverse effects of Cephalosporins

Hypersensitivity (type 1 anaphylaxis or type 4 rash)

- Disulfiram-like reaction (nausea, flushing, HA w/ alcohol consumption)

A patient had a recent severe hypersensitivity reaction to a Penicillin. Should you give a Cephalosporin instead?

The disulfiram-like reaction seen as an adverse effect to Cephalosporins results from an inhibition of what enzyme? Which causes a build-up of what?

Aldehyde dehydrogenase Acetaldehyde

A patient is on Warfarin (or has coagulation issues) and develops an independent bacterial infection. You consider administering a Cephalosporin. Which TWO should you be CAUTIOUS of? Why?

- Cefotetan (2nd gen.) - Cefaperazone (3rd gen.) Cause reduced vitamin-K production by GI bacteria --> deficient prothrombin --> BLEEDING potential

Monobactam - drug name (1)

Aztreonam

Aztreonam is effective against which organisms?

Gram (-) rods (Klebsiella, Pseudomonas, Serratia, etc.)

Aztreonam - MoA Is it active against Gram (+) organisms? Why or why not?

Inhibition of PBP3 NO - the PBP3 is only on gram (-) rods

Is Aztreonam a 1st line therapy? Solo empiric therapy? When/how is it used generally?

NO and NO - SUBSTITUTE for Ampicillin/Amoxicillin or Gen 3/4 Cephalosporins IF hypersensitive to these

How is Aztreonam administered?

Parenteral

A severely ill hospitalized patient needs empirical antibiotic therapy for several bacteria, including Gram (+) and Gram (-), as well as Methicillin-sensitive (beta-lactamase) organisms. Good potential option (class)?

Carbapenems

Adverse effects of Carbapenems

- Nephrotoxicity - CNS toxicity (seizures, confusion) - Hypersensitivity and rash (caution w/ penicillin allergy)

Imipenem/Cilastatin combo - explain

Imipenem (Carbapenem) is metabolized to a NEPHROTOXIC metabolite via DIPEPTIDASE enzyme. Cilastatin is a DIPEPTIDASE INHIBITOR, thus preventing the nephrotoxicity and prolonging the effects of Imipenem

Meropenem - benefits over Imipenem (2)

- NOT nephrotoxic OR CNS toxic (less seizure risk) | - Better for bacterial meningitis and intra-abdominal infection

TO REVIEW: Vancomycin is used for which 2 things?

1. Penicillin hypersensitivity | 2. MRSA or PRSP (penicillin-resistant strep. pneumoniae)

How does Erythromycin differ from Vancomycin? (2)

- MSSA, NOT MRSA or PRSP | - Oral (outpatient) rather than IV Vancomycin (inpatient)

***Use of Clindamycin

WITH Beta Lactam drug - to decrease production of necrotizing/toxic metabolites by certain strep/staph infections that would otherwise cause toxic shock or necrotizing fasciitis ("skin-eating bacteria")