Cephalosporins: Broad-Spectrum Antibiotics with 5 Generations

Cephalosporins are a group of broad-spectrum antibiotics widely used to treat bacterial infections. They have a similar chemical structure to penicillin but have a broader spectrum of antimicrobial activity and are less susceptible to degradation by bacterial beta-lactamases.

Cephalosporin Classification:

1. Classification based on antibacterial spectrum:

• Narrow-spectrum cephalosporins: Primarily active against Gram-positive bacteria.

• Broad-spectrum cephalosporins: Active against both Gram-positive and Gram-negative bacteria.

2. Classification based on generation:

Cephalosporins are classified into five generations, each generation having distinct characteristics regarding their antibacterial spectrum, resistance to beta-lactamases, and pharmacokinetics.

Note:

• The five-generation classification system applies only to the first four generations (generations 1 to 4).

• Generation 1: Strong activity against Gram-positive bacteria, weaker activity against Gram-negative bacteria.

• Generation 2: Decreased activity against Gram-positive bacteria, increased activity against Gram-negative bacteria.

• Generation 3: Further decreased activity against Gram-positive bacteria, stronger activity against Gram-negative bacteria, including some strains of Pseudomonas aeruginosa.

• Generation 4: Strong activity against both Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa.

• Generation 5: Strong activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) strains.

List of Cephalosporins by Generation:

1. Generation 1:

• Cefalexin: Oral administration, narrow-spectrum, primarily used to treat upper respiratory tract infections, skin, and soft tissue infections.

• Cefazolin: Intravenous administration, narrow-spectrum, widely used for infection prophylaxis, particularly in surgical infections (e.g., cardiovascular surgery, orthopedic surgery, gastrointestinal surgery). It effectively eliminates S. aureus (+) and has a long half-life.

2. Generation 2:

• Cefaclor: Oral administration, broader spectrum than cefalexin, commonly used to treat upper respiratory tract infections, otitis media, sinusitis, skin, and soft tissue infections.

• Cefuroxime: Intravenous or oral administration, broader spectrum of activity than cefaclor, used to treat lower respiratory tract infections, urinary tract infections, meningitis, skin, and soft tissue infections.

• Cefoxitin: Intravenous administration, effective against Gram-negative anaerobic bacteria, used to treat intra-abdominal infections, pelvic infections, genitourinary infections, and endocarditis.

• Cefotetan: Intravenous administration, effective against Gram-negative anaerobic bacteria, used to treat intra-abdominal infections, pelvic infections, genitourinary infections, and endocarditis.

3. Generation 3:

• Cefixime: Oral administration, broad-spectrum, used to treat upper respiratory tract infections, urinary tract infections, skin, and soft tissue infections.

• Ceftazidime: Intravenous administration, effective against Pseudomonas aeruginosa, used to treat lower respiratory tract infections, urinary tract infections, skin, and soft tissue infections, meningitis.

• Ceftibuten: Oral administration, broad-spectrum, used to treat upper respiratory tract infections, urinary tract infections, skin, and soft tissue infections.

• Ceftriaxone: Intravenous administration, effective against Pseudomonas aeruginosa, used to treat lower respiratory tract infections, urinary tract infections, skin, and soft tissue infections, meningitis, bacteremia.

4. Generation 4:

• Cefepime: Intravenous administration, strong activity against both Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa, used to treat lower respiratory tract infections, urinary tract infections, skin, and soft tissue infections, meningitis.

5. Generation 5:

• Ceftaroline: Intravenous administration, strong activity against both Gram-positive and Gram-negative bacteria, including MRSA, used to treat skin and soft tissue infections, lower respiratory tract infections, pneumonia, and bacteremia.

Precautions when using Cephalosporins:

• Cephalosporins can cause allergic reactions, especially in individuals with a penicillin allergy.

• Cephalosporins may cause side effects such as nausea, vomiting, diarrhea, abdominal pain, rash, itching, dizziness, and headache.

• Inform your doctor about your medical history before taking cephalosporins.

• Follow your doctor’s instructions regarding dosage and duration of use.

• Do not discontinue cephalosporin use without your doctor’s approval.

Conclusion:

Cephalosporins are a widely used group of broad-spectrum antibiotics for treating bacterial infections. Each generation of cephalosporins possesses distinct characteristics regarding antibacterial spectrum, resistance to beta-lactamases, and pharmacokinetics. Selecting the appropriate cephalosporin for each patient depends on the type of bacteria causing the infection, the patient’s medical history, and the severity of the infection.