Which of the following is NOT a third-generation cephalosporin?

The correct answer is Cefepime, which is classified as a fourth-generation cephalosporin. Fourth-generation cephalosporins are known for their broader spectrum of activity, particularly against Gram-negative bacteria, and have enhanced stability against certain beta-lactamases. In contrast, the drugs listed as options A, B, and D—Cefoperazone, Cefotaxime, and Ceftizoxime—are all considered third-generation cephalosporins.

Third-generation cephalosporins often provide improved coverage against Gram-negative organisms compared to earlier generations while retaining some activity against Gram-positive strains. This classification highlights their evolving effectiveness in treating infections caused by a wider range of bacteria.

Understanding the distinctions between the generations of cephalosporins is crucial in pharmacology, especially for making informed decisions regarding antibiotic therapy.