ceph·​a·​lex·​in | \ ˌse-fə-ˈlek-sən How to pronounce cephalexin (audio) \

Definition of cephalexin

: a semisynthetic cephalosporin C16H17N3O4S with a spectrum of antibiotic activity similar to the penicillins

Examples of cephalexin in a Sentence

Recent Examples on the Web The most common organism responsible for perichondritis is a bug called Pseudomonas aeruginosa, a virulent pathogen with the ability to resist many antibiotics, including the cephalexin prescribed by Jessica’s pediatrician. Rick Pescatore, Philly.com, 20 Oct. 2017 Jessica’s pediatrician diagnosed a mild case of a bacterial skin infection known as cellulitis, and gave her a prescription for an antibiotic, cephalexin, along with the standard precautions. Rick Pescatore, Philly.com, 20 Oct. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'cephalexin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of cephalexin

1967, in the meaning defined above

History and Etymology for cephalexin

cephalosporin + -ex- (of unknown origin) + -in entry 1

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The first known use of cephalexin was in 1967

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Cite this Entry

“Cephalexin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cephalexin. Accessed 7 Oct. 2022.

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More Definitions for cephalexin


ceph·​a·​lex·​in | \ ˌsef-ə-ˈlek-sən How to pronounce cephalexin (audio) \

Medical Definition of cephalexin

: a semisynthetic cephalosporin C16H17N3O4S with a spectrum of antibiotic activity similar to the penicillins that is often administered in the form of its hydrochloride C16H17N3O4S·HCl or monohydrate C16H17N3O4S·H2O

Note: Cephalexin is marketed under the trademark Keflex.


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