What does cephalexin mean?
Cephalexin is a widely used oral antibiotic belonging to the cephalosporin class, specifically its first generation. Introduced commercially in the late twentieth century under the brand name Keflex, it works by disrupting the formation of bacterial cell walls, causing susceptible bacteria to die. Physicians frequently prescribe cephalexin for infections of the skin, ears, bones, respiratory tract, and urinary system, and it is available as capsules, tablets, and a liquid suspension suitable for children. Because it is chemically related to penicillins, patients with certain allergies must tell their doctor before taking it, although cross-reactivity is less common than once feared. Like all antibiotics, cephalexin is ineffective against viruses and loses value when overused, so completing the full prescribed course matters. Its name traces back to Greek roots via the mold genus Cephalosporium, from which this entire drug family takes its title.
nounA first-generation cephalosporin antibiotic used to treat bacterial infections such as those of the skin, respiratory tract, ear, bone, and urinary tract.
- A first-generation cephalosporin antibiotic, taken orally as capsules, tablets, or liquid, used against susceptible gram-positive and some gram-negative bacteria.
"The doctor prescribed cephalexin twice daily for ten days to clear up the skin infection."
"She was given cephalexin for the infected cut on her arm after the bacteria proved sensitive to it."
"Patients allergic to penicillin are sometimes prescribed cephalexin instead, though caution is still advised."
Rarely pluralized; the plural appears only informally when counting individual tablets or capsules.
"He had two cephalexins left in the blister pack."
Its name hides a Greek word for 'head' — cephalexin belongs to a family of antibiotics named after a mold that looked like a tiny head under the microscope.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cephalexin
Cephalexin combines elements drawn from the mold genus Cephalosporium, whose name comes from Greek 'kephalē', meaning head, referring to the fungus's appearance, together with a suffix characteristic of cephalosporin drug nomenclature. It was developed in the late twentieth century as one of the first oral first-generation cephalosporins and marketed under the brand name Keflex. The same Greek root gives English words such as cephalic, cephalopod, and encephalitis.
How cephalexin is actually used
A technical medical term, encountered mainly in prescriptions, patient information leaflets, and clinical discussion rather than everyday conversation. The spelling 'cefalexin' is an accepted variant in British usage. It should only be taken under medical direction, as misuse contributes to antibiotic resistance.
Easily confused with cephalexin
Amoxicillin is a penicillin-class antibiotic, whereas cephalexin is a first-generation cephalosporin; both treat similar infections but belong to different drug families.
Ciprofloxacin is a fluoroquinolone antibiotic reserved for different infection types, while cephalexin is an older cephalosporin often chosen for skin and soft-tissue infections.