Cephalosporins

Question 1

1st Gen cephalo

Answer 1

Cefazolin IV, IM
Cefadroxil (oral)
Cephalexin (Oral)

Spectrum

• Good gram +, mostly Cocci
• –> NOT enterococci, MRSA, or s. epidermis
• moderate gram -
• –> Good activity against ECOLI, klebsiella pneuomonia, proteus mirabilis

Question 2

2nd generation ceph

Answer 2

Cefoxitin (Mefoxin®) (IV IM) 
Cefaclor (Ceclor®) (ORAL) 
Cefuroxime (Zinacef®) (ORAL) 
Cefotetan (Cefotan®) (IV IM) 
Cefprozil (Cefzil®) (Oral) 
Loracarbef (Lorabid®) (oral) 

Spectrum
- increased Gram -ve coverage but much less than third gen

Question 3

3rd Generation Cephalo

Answer 3

- Cefotaxime 
Ceftizoxime
Ceftazidime 
Ceftriaxone 
Cefixime (Suprax®) (ORAL) 
Cefpodoxime Proxetil (Vantin®) (ORAL) 
Cefditoren (Spectracef®) (ORAL) 
Ceftarolime fosamil (ORAL) (Teflaro®) (IV/IM)
Ceftibuten (Cedax®) (oral) 
Cefdinir (Omnicef®) (oral)

• effective against gram =+ but less so
• more active against gram - esp enterobacteriaceae
• active againts penicillinase producing strains
• some active against p. aeurginosa

Question 4

3rd Gen Cephalosporins

- antipseudomonal

Answer 4

 Ceftizoxime (Cefizox®) antipseudomonal

 Ceftazidime (Fortaz®) antipseudomonal

Question 5

3rd Gen Cephalosporins

- CNS penetration

Answer 5

Ceftriaxone - substantail hepatic metabolism 
Cefotaxime Sodium (Claforan®)

Question 6

4th generation Cephalosproin

Answer 6

Cefepime 
IV/IM 
Eliminated in the kidney 
Eliminated by hemodialysis 
distributed to most body tissues and maybe the CNS

SE:

• alterations in lab values- specifically LFT, and inc. antibody levels based on coombs test but no evidence of hemolysis
• not nephrotoxic but if used with nephrotoxic drugs - risk of developing nephrotoxicity

Drug interactions
- probenacid can competitively inhibit renal tubular secretion of cefepime

Antibacterial Spectrum
- Gram + and gram -
- effective against s. pneumonia, s. aureus, and p. aureginosa, citerobacter, enterobacter,
ecoli, klebsiella, proteus, N. gonnorhea, Providencia,
shigella, salmonella, serratia, mycobacterium species

Question 7

5th Gen Ceph

Answer 7

Ceftarolime fosamil

• Only cephalosporin active against MRSA (high affinity for PBP 2A- MRSA PBP) and VRSA
• Used for complicated skin and skin structure infections
• no antipseudomonal activity

Excretion
- renal excretion

Question 8

Adverse Effects of Cephalosporins

Answer 8

 diarrhea
 Pseudomembranous colitis
 Leukopenia, thrombocytopenia, etc.
 Superinfection (enterococci, gram-negative bacilli, or candida) should
be kept in mind.
 disulfiram-like reaction after alcohol consumption (Cefamandole, etc.)
is possible.
 Rash, urticaria, fever, eosinophilia
 Direct and indirect positive Coombs tests. Hemolytic anemia, (but it is
not common or severe).
 G.I. symptoms: anorexia, nausea, vomiting, diarrhea. Diarrhea can be
severe enough to necessitate discontinuation of the drug.
 Dose-dependent renal tubular necrosis.
 Synergistic nephrotoxicity with aminoglycosides, especially in elderly
patients and in patients with decreased renal function.
 Overgrowth of resistant organism (Pseudomonas) at multiple sites
after long-term use.
 Candidiasis, usually in the mouth, after long-term use.

Question 9

Cephalosporin Clinical Use

Answer 9

DOC for:

• Moraxella catarrhalis – second or third generation
• Neisseria gonorrhoeae – ceftriaxone, cefixime
• E. coli, Klebsiella, Proteus – first or second generation
• Salmonella – third generation
• Penicillin resistant Streptococcus pneumoniae – ceftriaxone

Cephalosporins may be considered for treating a few infections such as:
- gram-positive infections in penicillin-sensitive patients
- mixed infections: Cephalosporins can be used for the treatment of cellulitis, or skin
ulcers in diabetics.
- Surgical prophylaxis (Cefazolin - 4 gram/day I.V.).
- Urinary tract infections.