Cephalosporin Pharmacology – Mnemonics

Cephalosporins are one of the most widely prescribed antimicrobial drugs. They can be classified into 5 to generations and the medical students often have hard time remembering the names of drugs falling into different generations as the names appear and sound similar. This is a collection of mnemonics from different sources.

Classification of Cephalosporins

Mnemonic for Oral and Parenteral Cephalosporins

Parenteral:

1. All 4th and 5th generation cephalosporins
2. Have “t” except ceftibuten and cefditoren
3. Having “z” – zone, zolin, zole

Oral: Have “OR” in the name – Cefaclor, Cefditoren, Loracarbef

Menmonic to remember classification by generation of Cephalosporins

A. 5th generation:

• With “ro” and “lo”: ceftobiprole, ceftaroline, ceftolozane

B. 4th generation:

• With “pi” and “qui”: Cefepime, Cefepirome, Cefquinome

C. 1st generation:

All cephalosporins having “A” after “Cef” are 1st generation except Cefaclor.

2 Xs and 1 Z in Dine

• 2 “X” – cefalexin, cefadroxil
• 1 “Z” – cefazolin
• 2 “IN” – cefalothin, cefaparin
• DINE – cephradine

D. 3rd generation:

Cephalosporins ending with “me” are 3rd generation except cefuroxime.

“cef” +/- (a,e,i,o,u) + p/d/t

• cefotaxime, ceftizoxime, ceftriaxone, ceftazidime, cefoperazone
• cefixime, cefpodoxime, cefdinir, ceftibuten, ceftamet

E. 2nd generation:

FURy FOX FOR FON TEA and 2 Ms for a Macho fox

• ceFURoxime, ceFOXitine, ceFORanide, ceFONicid, cefoTEtan
• cefMandole, cefMetazole
• Remember one more drug: Cefaclor

Flomoxef has been classified by different authors into different generations – 2nd, 3rd and 4th generations.

Short review of pharmacology of cephalosporins

A. Class: Beta-lactams (like Penicillin)

B. Mechanism of action: Disrupt cell wall synthesis by inhibiting transpeptidase (cross-linking)

C. Pharmacokinetics:

1. Most are excreted by kideny (tubular secretion).
2. 2 “Zones” are secreted in bile: Ceftriaxone and Cefoperazone

D. Blood brain barrier (BBB) penetration:

1. 1st generation: No BBB penetration
2. 2nd generation: Cefuroxime has highest among 2nd generation
3. 3rd generation: Except Cefoperazone and Cefixime

E. Spectrum of activity:

1. 1st generation: Mainly Gram+
   

   Gram – (PEcK): Proteus, E.Coli, Klebsiella

2. 2nd generation: Gram- > Gram+
   

   HEN PEcKS: Haemophilus influenzae, Enterobacter, Neissera, Proteus, E. Coli, Klebsiella, Serratia

3. 3rd generation: Gram – >> Gram +
   

   Ceftriaxone: Meningitis, Gonorrhea
   Ceftazidime and Cefoperazone: Pseudomonas
   Used to treat meningitis and sepsis (can cross Blood Brain Barrier)

4. 4th generation: Pseudomonas
5. 5th generation: MRSA

Activity against Bacteroides:

• 2nd generation: Cefoxitin, Cefotetan and Cefmetazole
• 3rd generation: Ceftizoxime (maximum)

Activity agaisnt pseudomonas:

• Ceftazidime (maximum)
• Ceftazolone
• Cefoperazone

Cephalosporins don’t have activity against: “LAME”

• Listeria
• Atypicals (including Mycoplasma and Chlamydia)
• MRSA (Except 5th generation)
• Enterococci

F. Drug of choice:

1. Surgical prophylaxis: Cefazolin
2. Melioidiosis (Burkholderia psudomalleri): Ceftazidime
3. Gonorrhea, salmonellosis (including typhoid), E. coli sepsis, Proteus, Serratia, Haemophilus and empirical therapy for bacterial
   meningitis: Ceftriaxone
4. Pseudomonal CNS infection: Ceftazidime or Cefepime or Meropenem (For GU and GI infections – Fluoroquinolones and Aminoglycosides)
5. Bacteroides: Metronidazole (Cefoxitin is an alternative along with clindamycin and chloramphenicol)

G. Adverse effects:

1. Drugs with methylthiotetrazole group: Cefamandole, Cefoperazone, Cefotetan, Moxalactam
   • Acts like oral anticoagulant (Vit. K antagonist): Bleeding (hypoporthrombinemia)
   • Disulfiram like reaction
2. Biliary sludging:
   • Ceftriaxone
   • Cefotaxime
3. Taste disutrbance: Ceftobiprole
4. Non-bloody red stools: Cefdinir
5. Nephrotoxicity:
   • Cephaloridine (highest nephrotoxicity)
   • Cephalothin
6. Neutropenia: Ceftazidime
7. Thrombophlebitis (Parenteral)
8. Diarrhea
9. Anaphylaxis

Mnemonic: “DDT HAPeNS”

D – diarrhea
D – disulfiram like reaction
T – thrombophlebitis
H – hypoprothrombinemia
A – allergy (hypersensitivity)
P – pain (severe with i.m.)
N – nephrotoxicity
S – super infections with fungi

H. Summary mnemonics for generation of cephalosporins:

• First Generation = “FA/PHA”
• Second Generation = “Everything Else”
• Third Generation = “ONE/TEN/IME”
• Fourth Generation = “PI” and “QUI”
• Fifth Generation = “ROL”

Dr. Sulabh Kumar Shrestha, MS Orthopedics

He is the section editor of Orthopedics in Epomedicine. He searches for and share simpler ways to make complicated medical topics simple. He also loves writing poetry, listening and playing music.