Cephalosporins Overview
- Penicillin Overview
- Penicillinase-Sensitive vs. Penicillinase-Resistant Penicillins
- Anti-Pseudomonal Penicillins
- Cephalosporins Overview
- 1st Generation Cephalosporins
- 2nd Generation Cephalosporins
- 3rd Generation Cephalosporins
- 4th Generation Cephalosporins
- 5th Generation Cephalosporins
- Carbapenems
- Monobactams (Aztreonam)
- Vancomycin
- Aminoglycosides
- Tetracyclines
- Tigecycline
- Chloramphenicol
- Clindamycin
- Linezolid
- Macrolides
- Polymyxins
- Sulfonamides
- Dapsone
- Trimethoprim
- Fluoroquinolones
- Daptomycin
- Metronidazole
- Rifamycins (Rifampin, Rifabutin)
- Isoniazid
- Pyrazinamide
- Ethambutol
- Chloroquine
Summary
Cephalosporins are a class of antibiotics ‘used to treat a variety of bacterial infections. Like penicillins, these drugs are beta-lactam antibiotics; they are D-Ala-D-Ala analogs that bind to and block the bacterial transpeptidase, thereby preventing the cross-linking of the bacterial cell wall. Cephalosporins are also resistant to penicillinase, a bacterial enzyme that can deactivate penicillins by cleaving the beta-lactam ring. Because of this, many cephalosporins can be used to treat penicillin-resistant bacteria. However, cephalosporins also have a host of their own side effects. Firstly, patients may develop an allergic reaction after taking cephalosporins, which usually manifests as a rash. Taking cephalosporins can also lead to creation of auto-antibodies that cause hemolytic anemia. Finally, a disulfiram-like reaction to alcohol and vitamin K deficiency are important side effects seen with taking cephalosporins.
Key Points
- Cephalosporins
- Mechanism
- Beta-lactam antibiotics
- Works in a similar fashion to penicillin to bind to penicillin-binding proteins (transpeptidases) and prevent cell wall cross-linking
- In penicillins, beta-lactam is bonded to a penam (thiazolidine) ring, and a side chain
- In cephalosporins, beta-lactam is bonded to a cepham dihydrothiazine ring
- Works in a similar fashion to penicillin to bind to penicillin-binding proteins (transpeptidases) and prevent cell wall cross-linking
- Bactericidal
- Beta-lactam antibiotics
- Clinical Use
- Different bacterial coverage dependent on generation of drug
- Adverse Effects
- Hypersensitivity (allergy)
- Most commonly seen with cefazolin administered pre-op
- Low rate of cross-allergenicity with penicillin-allergic patients
- Autoimmune hemolytic anemia
- Disulfiram-like reaction to alcohol
- Vitamin K deficiency
- May cause bleeding
- Increases nephrotoxicity of aminoglycosides
- Hypersensitivity (allergy)
- Resistance
- Resistant to penicillinase (beta-lactamase)
- Esp. later generation (e.g. 3rd generation), explains why they have more gram-negative activity
- Resistance develops by
- Structural change in penicillin-binding proteins (transpeptidases)
- Production of cephalosporinases
- Resistant to penicillinase (beta-lactamase)
- Mechanism