Erdman ceph Flashcards
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
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
Mechanisms of resistance
Beta lactamase production
Alteration in PBP (MRSA, PRSP)
Alteration of outer membrane and less drug penetration
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
1st gen ceph coverage gram negative
P - proteus mirabilis
E - E. Coli
K - klebsiella pneumoniae
Cefazolin
to 1st gen cephalosporin
Used IV
Great for MSSA
Cephalexin
1st gen cephalosporin
Used PO
Brand names: Keflex, Keftab, Biocef
Second Gen cephalosporins
Cephalosporins, cephamycins, and carbacephems Several agents in this class have anaerobic activity(cephamycins)
Second Gen Ceph Gram + coverage
Group streptococci
Viridans streptococci
Penicillin susceptible s. Pneumoniae
Methicillin susceptible staph aureus (target)
(same as 1st gen)
Second Gen Ceph gram - coverage
H- H. influenzae E - Enterobacter spp. (some) N - neisseria spp P - proteus mirabilis E - E. coli K - K. pneumoniae
ONLY cephalosporins that have activity against anaerobes (class and drugs)
Cephamycins (cefotoxin, cefotetan, cefmetazole)
These anaerobes are below the diaphragm and include bacteroides
Cefuroxime
2nd gen ceph
Used IV and PO
Brand names:kefurox, Zenacef
Will work on CSF infections but is no longer recommended.
Cefprozil
2nd gen ceph
Very common drug (most common 2nd gen)
Brand: Cefzil
Cefoxitin
2nd gen ceph
is a cephamycin so has anaerobic coverage!
Brand (Mefoxin)
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)
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
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
