Cephalosporins, which were discovered in the 1950s, are a type of antibiotic related to penicillin. Like penicillin, the medicines are derived from a fungus—in their case, Cephalosporium acremonium. Based on that original drug, scientists have created dozens of similar antibiotics to treat a wide range of diseases, from meningitis to gonorrhea.

Both cephalosporins and penicillin are beta-lactam antibiotics, meaning that their molecular structure includes a beta-lactam ring consisting of three carbon atoms and one nitrogen atom. They are bactericidal, which means that they kill bacteria. They work by breaking down peptidoglycan, a polymer that’s needed for building cell walls. Because of the similarities between the two drugs, cephalosporins are often prescribed to people who have infections that are resistant to penicillin. Among their many capabilities, cephalosporins are used to treat ear, nose, throat, skin, or sinus infections; pneumonia; staph infections; and bronchitis. They are available in prescription-strength tablets, capsules, and liquids, as well as injectable forms.

First-generation (and newer, fourth-generation) cephalosporins are moderate- to broad-spectrum antibiotics generally effective against many different types of ailments. Gram-positive bacteria with high amounts of peptidoglycan in their cell walls—so named because they turn dark blue or violet when stained with dye in a process known as Gram staining—respond well to cephalosporins, as do many gram-negative bacteria that have just a thin peptidoglycan layer. For bacteria that are resistant to the first-generation cephalosporins, second- and third- generation drugs were developed. Allergic reactions to cephalosporins can include shortness of breath, a pounding heartbeat, a skin rash or hives, cramps or stomach pain, fever, diarrhea, and unusual bleeding or bruising.

ADDITIONAL FACTS

  1. The ability of many cephalosporin derivatives to penetrate the cerebro spinal fluid makes them effective in treating meningitis.
  2. Cephalosporins named before 1975 are spelled with ph (cephalexin, for example), while those named later are spelled with f (such as cefadroxil).
  3. A newly developed drug called ceftobiprole has been described as a fifth-generation cephalosporin.