Antibiotics - Cephalosporins: Nursing pharmacology

Cephalosporins are a large group of broad-spectrum antibiotics, which can be used to treat a wide variety of bacterial infections, including meningitis, pneumonia, urinary tract infections, and sepsis. These antibiotics get their name from Cephalosporium acremonium, a fungus from which they are derived.

Now, cephalosporins belong to beta-lactam antibiotics, which means they have a beta-lactam ring in their core, and they mainly work by disrupting the synthesis of the peptidoglycan layer, a major component of bacterial cell walls. This weakens the bacterial cell wall, ultimately killing the bacteria.

Now, cephalosporins are typically classified into five generations, each being used to treat certain types of bacterial infections.

First-generation cephalosporins include cephalexin, which is administered orally; cefadroxil, which is administered orally and intravenously; and cefazolin, which is given intravenously and intramuscularly.

In general, first-generation cephalosporins are effective against most gram-positive bacteria, such as Staphylococci and Streptococci species; as well as some gram-negative bacteria like Escherichia coli, Proteus mirabilis, and Klebsiella pneumonia.

So, first-generation cephalosporins are used to treat respiratory tract infections, urinary tract infections, some skin infections; and bone and joint infections. They can also be given as surgical antibiotic prophylaxis, to prevent infections from spreading to deeper tissues during surgical operations.

Next, second-generation cephalosporins include cefaclor and cefprozil which are administered orally; as well as cefotetan and cefoxitin, which are given intravenously and intramuscularly; and cefuroxime, which is given orally and intravenously.

Compared to the first generation, second-generation cephalosporins are less effective against Staphylococcus species. Instead, they are more effective against certain types of gram-negative bacteria, such as Haemophilus influenzae, which can cause infections like otitis media, respiratory tract infections, or septicemia; as well as Bacteroides, which can causes infections like osteomyelitis, septic arthritis, and meningitis.

Moving on, third-generation cephalosporins include ceftriaxone, cefotaxime, and ceftazidime, which are administered intravenously and intramuscularly; and cefixime, which is taken orally. This group of antibiotics has some effectiveness against gram positive bacteria, such as Streptococcus pneumoniae, but far less than the first generation.

Instead, third-generation cephalosporins are effective against a large family of gram-negative bacteria known as Enterobacteriaceae, which include bacteria such as Escherichia coli, Proteus mirabilis, Klebsiella species, Enterobacter species, and Serratia species. They’re also effective against other gram negatives, such as Haemophilus influenzae and the Neisseria species.

This makes third-generation cephalosporins a perfect choice to use for the initial management of infections like meningitis and septicemia. In addition, they can be used to treat infections like otitis media, pelvic inflammatory disease, or skin and soft tissue infections.

Next, fourth-generation cephalosporins include cefepime, which is administered intravenously or intramuscularly. This medication has some activity against Streptococcus pneumoniae and Staphylococcus species, but is most effective against gram-negative bacteria, and can be used to treat infections involving the respiratory tract, urinary tract, skin, and intra-abdominal infections.

Finally, the main fifth-generation cephalosporin is ceftaroline, which is administered intravenously. It is most effective against gram-positive bacteria, and is mainly used to treat community-acquired pneumonia, and bacterial skin infections.

Common side effects associated with cephalosporins include headaches, dizziness, nausea, vomiting, and diarrhea. In addition, cephalosporins may disrupt the healthy intestinal flora, which can allow certain bacteria like Clostridioides difficile to survive and overgrow within the gastrointestinal tract, rarely but potentially leading to Clostridioides difficile infection or CDI for short.