Cephalosporins

Summary

Cephalosporins are a class of antibiotics that are used to treat a wide variety of bacterial infections. Cephalosporins are easy to recognize because they all start with “ceph-”, like ceftriaxone, cefazolin, and cephalexin. Cephalosporins can have a cross sensitivity with penicillins, so if a patient is allergic to one, the severity of the allergic reaction should be determined before giving the other. Patients taking cephalosporins should avoid alcohol to prevent a disulfiram-like reaction. Cephalosporins can cause bleeding so other drugs that cause bleeding should be avoided, like NSAIDs and anticoagulants.

Key Points

• Cephalosporins
  • Key Drugs
    • Cef-, Ceph-
      • Ceftriaxone (Rocephin)
      • Cefazolin (Ancef)
      • Cephalexin (Keflex)
    • There are 5 different generations of cephalosporins and each generation has coverage for a slightly different spectrum of bacteria
  • Mechanism
    • Beta-lactam Antibiotic
      • Inhibits bacterial cell wall synthesis
  • Clinical Uses
    • Bacterial infections
      • Surgical infection prophylaxis against skin flora
      • Otitis media
      • Meningitis
      • Appendicitis
      • Urinary Tract Infections
      • Respiratory Infections
      • Etc.
  • Side Effects and Adverse Reactions
    • Cross-sensitivity with penicillins
      • The structure and function of cephalosporins is similar to that of penicillins (beta lactam antibiotics) so there can be cross sensitivity
      • Cross-allergenicity rates are relatively low (only about 1-4%)
      • If the patient has a penicillin allergy, the order for cephalosporins should be questioned.
    • Disulfiram-like reaction
      • Do not take with alcohol
    • Bleeding
      • Secondary to vitamin K deficiency, as cephalosporin prevents vitamin K activation which is required for the synthesis of blood clotting factors
      • Thrombocytopenia
      • Avoid drugs that may promote bleeding (e.g. NSAIDS, anticoagulants)
    • Clostridium Difficile overgrowth
      • Broad-spectrum antibiotics like cephalosporins can cause C. difficile overgrowth by killing existing gut flora to open a niche.
      • Cephalosporins cannot treat C. difficile infections
      • Severe diarrhea should be reported, as it may indicate a c. diff. infection
      • Other types of superinfection secondary to antibiotic use include yeast (Candida) infections.
    • GI Distress (nausea, vomiting, diarrhea, anorexia)
      • May be taken with food to reduce GI distress