What type of infection is Cephalexin least effective against?

Cephalexin is classified as a first-generation cephalosporin antibiotic, primarily effective against certain types of bacterial infections. Its mechanism involves inhibiting bacterial cell wall synthesis, which makes it effective against both gram-positive and some gram-negative bacteria.

Viral infections, such as those caused by the influenza virus or other viruses, do not respond to antibiotics, including cephalexin, because they do not involve bacterial growth. Antiviral medications are necessary to treat viral infections. As such, when considering the types of infections for which cephalexin is prescribed, it becomes clear that it is not suitable for managing viral infections, confirming that this type of infection is where cephalexin is least effective.

In contrast, cephalexin can effectively treat skin infections caused by susceptible bacteria, urinary tract infections, and certain types of bone infections. Each of these conditions is typically associated with bacterial pathogens, which are the primary targets for cephalexin therapy.