Erdman ceph Flashcards by Austin D

Class generalizations

Generally short half life and frequent dosing
Except ceftriaxone which has 8hr half life and a carbapenam.

Eliminated unchanged renally except ceftriaxone, cefoperazone, nafcilin, and oxacillin.

No enterococcus coverage at all

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General structure

House with garage and basement
Position 7-bacterial activity
Position 3-kinetics activity

6 member ring helps create extra protection against some beta lactamases

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Mechanisms of resistance

Beta lactamase production

Alteration in PBP (MRSA, PRSP)

Alteration of outer membrane and less drug penetration

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1st gen ceph coverage gram positive

Group streptococci
Viridans streptococci
Penicillin susceptible s. Pneumoniae
Methicillin susceptible staph aureus (target)
**Best gram + aerobe coverage of all cephs

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1st gen ceph coverage gram negative

P - proteus mirabilis
E - E. Coli
K - klebsiella pneumoniae

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Cefazolin

to 1st gen cephalosporin
Used IV
Great for MSSA

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Cephalexin

1st gen cephalosporin
Used PO
Brand names: Keflex, Keftab, Biocef

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Second Gen cephalosporins

Cephalosporins, cephamycins, and carbacephems
Several agents in this class have anaerobic activity(cephamycins)

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Second Gen Ceph Gram + coverage

Group streptococci
Viridans streptococci
Penicillin susceptible s. Pneumoniae
Methicillin susceptible staph aureus (target)

(same as 1st gen)

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Second Gen Ceph gram - coverage

H- H. influenzae
E - Enterobacter spp. (some)
N - neisseria spp
P - proteus mirabilis
E - E. coli
K - K. pneumoniae

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ONLY cephalosporins that have activity against anaerobes (class and drugs)

Cephamycins (cefotoxin, cefotetan, cefmetazole)

These anaerobes are below the diaphragm and include bacteroides

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Cefuroxime

2nd gen ceph
Used IV and PO
Brand names:kefurox, Zenacef
Will work on CSF infections but is no longer recommended.

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Cefprozil

2nd gen ceph
Very common drug (most common 2nd gen)
Brand: Cefzil

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Cefoxitin

2nd gen ceph
is a cephamycin so has anaerobic coverage!
Brand (Mefoxin)

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3rd gen cephalosporin class and positive coverage

Some coverage over some Beta lactamase producers

Ceftriaxone has coverage over gram positive aerobes and penicillin-resistant S. pneomoniae (PRSP)

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3rd gen cephalosporin gram - coverage

H- H. influenzae
E - Enterobacter spp
N - neisseria spp (including Blactamase N. gonorrhea)
P - proteus mirabilis
E - E. coli
C - Citrobacter sp
K - K. pneumoniae
S - Serrratia marcescens
S - Salmonella sp
S - Shigella sp

Also pseudomonas aeruginosa (target) is covered by ceftazidime and cefoperazone

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Ceftriaxone

3rd gen ceph
Brand: Rocephin

Elimination is biliary
8hour half life provides allows once daily dosing

**retains gram positive coverage, INCLUDING penicillin-resistant S. pneumoniae (PSRP)

**NO pseudomonas aeruginosa coverage

Ceftazidime

3rd gen cephalosporin

Brand: Fortaz, Tazicef

Cefpodoxime

3rd gen ceph
Used PO
Brand: Vantin

Fourth gen cephalosporins

Gram positive coverage similar to ceftriaxone (good)
Gram negative coverage similar to ceftazidime, including pseudomonas aeruginosa and Beta lactamase producing enterobacter sp.

**stable against Beta lactamases and are weak inducers of AmpC

**only current agent is Cefepime

Cefepime

4th gen cephalosporin

Only agent currently available in this class

Anti-MRSA cephalosporins

Gram + coverage similar to ceftriaxone, but also has activity against MRSA.**
Gram - coverage similar to ceftriaxone (does NOT cover pseudomonas aeruginosa)**
**Only ceftaroline is available

ceftaroline

Only available anti-MRSA cephalosporin

**Does NOT cover pseudomonas aeruginosa

Cephalosporin Beta Lactamase Inhibitor Combination

Ceftolozane -Tazobactam
Gram + coverage is streptococcus
Gram - coverage is similar to cefepime(4th gen), incuding resistant pseudomonas aeruginosa

**Approved 12/2014, only current agent

General cephalosporin guidelines of activity

``` NOT good against: MRSA (except ceftaroline) Enterococcus spp Listeria C. diff Atypical like legionella stenotrophomonas maltophilia (except ceftazidime) ```

Synergy against Viridans strep

Ceftriaxone with gentamicin

Synergy against staph aureus

cefazolin plus gentamicin

Synergy against gram negative aerobes

ceftriaxone, ceftazidime, or cefepime plus gentamicin, tobraymycin, or amikacin

Treating CSF conditions (meningitis)

will ONLY work with parenteral cefuroxime, most 3rd and 4th gen agents at max doses will * *NO FIRST GENS!** * *Cefuroxime is no longer recommended for meningitis**

Cephalosporin elimination

Most are eliminated unchanged by the kidneys, so most require renal adjustment. General T1/2 is 2 hrs * *Ceftriaxone is biliary, 8 hr half life * *Cefoperazone is liver

Uses of 1st gen ceph

Especially good for endocarditis and bacteremia due to MSSA Surgical prophylaxis

Uses of 3rd gen cephs

Ceftazidime is good if pseudomonas is suspected or documented Ceftriaxone is good for uncomplicated gonorrhea (one IM dose), community aquired pneumonia, (CAP), PRSP, viridans strp endocarditis

Uses of 4th gen cephs

Cefepime is especially good for pseudomonas

Hypersensitivity

IgM or IgG - responsible for rash and itching, can try a cephalosporin IgE - responsible for septic shock, avoid any cephalosporins, PCN, etc in these patients 5-15% cross reactivity with penicillin

Adverse effects due to MTT side chain

Cefamandole, cefotetan, cefmetazole, cefoperazone, moxalactam Hypothrombinemia - reduction in vit. K producing bacteria in GI leads to low levels Ethanol intolerance - disulfuram like reaction for about 24 hrs

IV interactions

IV calcium and ceftriaxone precipitates (wait 24hrs) Cefepime and ceftazodine can cause non-convulsive status epilepticus if pt. has renal insufficiency (delirium, mental status change)

GI effects

common to cause C. diff and increase in bilirubin from ceftriaxone

Agents not renally eliminated

Nafcilin, oxacillin, ceftriaxone, cefoperazone

MTT side chain

Cefamandole, cefotetan, cefmetazole, cefoperazone, moxalactam Cause disulfiram like reaction and hypoprothrombinemia due to decrease in it K producing bacteria in the Gi tract.

Ceftriaxone same line incompatibilities

Do not use with IV calcium. If giving calcium, must wait 24 hours after giving antibiotic.

Agents that are associated with nonconvulsive status epilepticus

Cefepime and ceftazidime