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Flashcards in PCN/CPH Deck (33)
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1

PO PCN

- Natural PCN (PCN VK)
- Anti-staph PCN (Dicloxacillin)
- AminoPCN (Amoxicillin)
- Augmented AminoPCN (amox/clav)

2

IV PCN

- Natural PCN (PCN G)
- Anti-staph PCN (Nafcillin)
- AminoPCN (ampicillin)
- Augmented AminoPCN (amp/sulbactam)
- Extended-spectrum PCN (piptaz)

3

PCN and Cephalosporin MOA

Arrest cell wall synthesis by binding to PBPs

**bacteria need to be actively dividing for B-lactams to work

4

PCN and Cephalosporin Mechanism of Resistance

1. destruction of abx by b-lactamases
2. failure of abx to penetrate to PBP targets
3. low-affinity binding of abx to PBP

5

PCN Pharmacology

- minimal drug interactions
- most renal excretion (except Nafcillin)
- time-dependent killing
- bactericidal

coverage:
- natural PCNs & anti-staph PCNs have good G+ activity
- as generations increase you lose G+ and gain G-

6

PCN ADRs

Class Effect:
- hypersensitivity rxn
- drug fever (rare)

Unique:
- **nafcillin: phlebitis, AIN, hypokalemia
- **clavulanate: diarrhea, hepatotoxicity (subclinical LFT elevations)

7

Natural PCNs

- PCN G (IV) or PCN VK
- Benzathine PCN (IM)

Common Indications:
- strep pharyngitis* / cellulitis
- various stages of syphilis*

Benzathine IM - think of as long acting IM shot

8

Anti-Staphylococcal PCNs

- Nafcillin (IV) or dicloxacillin (tab)

Common Indications:
- SSTIs* (esp when S. aureus suspected)

9

AminoPCNs

- Ampicillin (IV) or amoxicillin

Common Indications:
- URTIs* (pharyngitis, AOM secondary bacterial infection)
- streptococcal skin infections
- endocarditis prophylaxis for dental procedures*
- lyme disease*

10

Augmented AminoPCN

- amp/sul (IV) or amox/clav

Common Indications:
- animal/human bite prophylaxis or tx*
- amoxicillin failure URTIs (AOM, sinusitis, AE-COPD)*
- recurrent streptococcal pharyngitis
- SSTIs
- dental infections*

11

How do you prescribe amoxicillin/clavulanate?

Dose is based on amoxicillin component.

Determine appropriate dose and choose correct product (products are not interchangeable)

"Hardest abx to prescribe," says Paxty

12

Extended-Spectrum PCNs

- Pip/Taz (IV)

Common Indications:
- mostly nosocomial infections
- "serious outpatient --> inpatient infections (e.g. perforated diverticulum)

13

PO Cephalosporins

1st gen - cephalexin
2nd gen - cefuroxime
3rd gen - cefpodoxime

14

IV Cephalosporins

1st gen - cefazolin
2nd gen - cefuroxime
3rd gen - ceftriaxone
4th gen - cefepime
5th gen - ceftaroline

15

Cephalosporin Pharmacology

- minimal drug interactions
- most renal excretion (least with ceftriaxone)
- time-dependent killing
- bactericidal

Coverage:
- 1st/2nd gen: good G+
- increase generations generally lose G+ and gain G- (except 5th gen)

- no cephalosporin covers Enterococci or Listeria*

16

Cephalosporin ADRs

Class effect
- hypersensitivity rxn
- drug fever (rare)

Unique effects
- serum-sickness like rxn common w/cefaclor
- ceftriaxone & neonates* --> precipitates w/Ca2+ --> pseudocholelithiasis (precipitates in baby's lungs)

17

1st Gen Cephalosporin

- cefazolin (IV) or cephalexin

Common Indications:
- SSTIs*
- Streptococcal pharyngitis
- Lower UTI (cystitis) - good in pregnancy*
- perioperative prophylaxis (cefazolin)*

18

2nd Gen (Respiratory*) Cephalosporins

- cefuroxime (tab, IV)

Common indications
- amoxicillin failure URTIs (AOM, sinusitis, AE-COPD)*
- SSTIs

19

3rd Gen Cephalosporin - PO

- cefpodoxime, cefdinir

Common Indications:
- essentially the same as cefuroxime

20

3rd Gen Cephalosporin - PAR

- ceftriaxone (IM, IV)

Common Indications:
- refractory AOM
- CAP (w/azithromycin)*
- meningitis*
- gonorrhea*
- intraabdominal infection (e.g. pyelonephritis, diverticulitis)*
- serious lyme disease (heart, CNS)

21

4th Gen Cephalosporins

- cefepime (IV)

Common Indications
- mostly nosocomial infections

22

5th Gen Cephalosporins

- ceftaroline (IV)

strong affinity for PBP2a (modified PBP in MRSA) & PBP2x (modified PBP in PCN-resistant S. pneumoniae) --> 1st cephalosporin with any MRSA activity*

doesn't have extended GNB coverage that you might expect from higher-generation cephalosporin*

23

Natural PCN Coverage

PCN G (IV) or PCN VK
Benzathine (IM)

- S. pyogenes (GAS) & T. pallidum

24

Anti-Staphylococcal PCN Coverage

Nafcillin (IV) or dicloxacillin (tab)

- S. aureus (MRSA) & S. pyogenes (GAS)

25

AminoPCNs Coverage

Ampicillin (IV) or amoxicillin

- S. pyogenes
- S. pneumoniae
- S. galactiae (GBS)
- Enterococci
- B. burgdorferi
- P. multocida
- Proteus
- Listeria

Some: H. influenzae, E. coli

26

Augmented AminoPCN Coverage

Amp/Sul (IV) or Amox/Clav

Same as AminoPCN PLUS
- M. catarrhalis
- H. influenzae
- Most anaerobes
Some: E. coli, Klebsiella

27

Extended Spectrum PCN Coverage

Pip/Taz (IV)

GPC:
- S. pyogenes
- S. pneumoniae
- S. agalactiae (GBS)
- Enterococci

GNB:
- M. catarrhalis
- H. influenzae
- Proteus
- E. coli
- Klebsiella
- Enterobacter
- Serratia
- Pseudomonas ** - only anti-pseudomonal PCN

Most anaerobes

"Thou shall not use Zosyn every time"

28

1st Gen Ceph Coverage

Cefazolin (IV) or cephalexin

- S. pyogenes (GAS)
- S. aureus (MSSA)

Some: E. coli, Klebsiella, Proteus

29

2nd Gen Ceph Coverage

Cefuroxime (tab, IV)

Same as 1st gen PLUS
- S. pneumoniae
- M. catarrhalis
- H. influenzae
- Pasteurella

"Similar to augmentin-ish"

30

3rd Gen Ceph PO Coverage

Cefpodoxime & Cefdinir

Similar coverage as cefuroxime BUT more GNB acitivity...but cefuroxime is no longer suspension*