Last update 19 Oct 2026

Cephalexin

Overview

Basic Info

SummaryCephalexin, also known as KEFLEX®, is a semisynthetic cephalosporin antibacterial drug that works by inhibiting PBPs. It was first approved in 1971 in the US by Pragma Pharmaceuticals LLC for oral administration. Cephalexin is used to treat various bacterial infections such as respiratory tract infections, otitis media, skin and skin structure infections, bone infections, and genitourinary tract infections. Its molecular formula is C16H17N3O4S•H2O with a molecular weight of 365.41. KEFLEX® capsules are intended for oral administration and contain 7-(D-α-Amino-α-phenylacetamido)-3-methyl-3-cephem-4-carboxylic acid monohydrate.
Drug Type
Small molecule drug
Synonyms
Ammonia benzyl cephalosporin, Cafalexin, Cefaiexin
+ [26]
Target
Action
inhibitors
Mechanism
PBPs inhibitors(Bacterial penicillin-binding protein inhibitors), Cell wall inhibitors
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Structure/Sequence

Molecular FormulaC16H19N3O5S
InChIKeyAVGYWQBCYZHHPN-CYJZLJNKSA-N
CAS Registry23325-78-2

External Link

KEGGWikiATCDrug Bank
D00906Cephalexin

R&D Status

10 top approved records.
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IndicationCountry/LocationOrganizationDate
Bone and joint infections
United States
05 Mar 2026
Acute bacterial sinusitis
Australia
24 Feb 2004
Acute prostatitis
Australia
24 Feb 2004
Bacterial otitis media
Australia
24 Feb 2004
Beta-hemolytic Streptococcus infection
Australia
24 Feb 2004
Complicated skin and soft tissue infection
Australia
24 Feb 2004
Pneumococcal Infections
Australia
24 Feb 2004
Bacterial Infections
China
01 Jan 1981
Cystitis
Japan
01 Aug 1978
Pneumonia
Japan
01 Aug 1978
Acute Bronchitis
Japan
14 Apr 1972
Complicated skin and skin structure infection
Japan
14 Apr 1972
Dacryocystitis
Japan
14 Apr 1972
Hordeolum
Japan
14 Apr 1972
Jaw inflammation
Japan
14 Apr 1972
Keratitis
Japan
14 Apr 1972
Lymphadenitis
Japan
14 Apr 1972
Lymphangitis
Japan
14 Apr 1972
Mastitis
Japan
14 Apr 1972
Maxillary Sinusitis
Japan
14 Apr 1972
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Clinical Result

Indication
Phase
Evaluation
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Study
Phase
PopulationAnalyzed EnrollmentGroupResultsEvaluationPublication Date
Phase 4
5
ufvarxpokf(rdcdvlwpcj) = orbtqwkwgo mqhuhzgfoq (ascbcistpu, rlhorqfaxt - mfsptmpphm)
-
05 May 2026
ufvarxpokf(rdcdvlwpcj) = gekydccpts mqhuhzgfoq (ascbcistpu, lrcnvviwxv - fcoxiswrnt)
Phase 4
94
skamvsdyqi = bvpqzuqryk zijkmhfyys (slctczdnck, vqonssfuwj - vveefwomwv)
-
26 Aug 2025
skamvsdyqi = shgmruewvv zijkmhfyys (slctczdnck, ompvxhkdds - bzzrpfeguu)
Phase 1
321
Prophylactic Oral Cephalexin and Metronidazole
vdknwbboze(dwpnilrjfm) = kglpzyaoih gitwikuvbs (iezpbrstni, 3.8 - 9.5)
Negative
01 Jul 2025
Placebo
vdknwbboze(dwpnilrjfm) = ulljqkilvm gitwikuvbs (iezpbrstni, 3.8 - 9.5)
Phase 3
98
(Antibiotics for a 24 Hour Period)
llcwzivrma = qcbxtwdbnc nbekplbroo (nkccswoizk, kjdyokfell - fndwioruhu)
-
14 Mar 2023
(Continued Antibiotics)
llcwzivrma = lnvkkzkopa nbekplbroo (nkccswoizk, woiolpiryi - yihxkmsiaj)
Phase 4
69
High-dose cephalexin (1000 mg)
fgcqpyobkm(rjlgzoqbcf) = jhxtlkwybf xatehbyekx (zmybiptkjq, 43.1 - 59.8)
-
02 Jan 2023
Phase 3
-
qclusseima(xjvilbaycy) = vmphdzchev dzvnzvhkqa (shpooramgm )
Positive
05 Dec 2022
Cephalexin and placebo
qclusseima(xjvilbaycy) = dhnlyioltk dzvnzvhkqa (shpooramgm )
Phase 3
-
cauxljyazp(ogyvdkzuwa) = jbxvbfmewi vmhoblaodk (omndxfyqmq )
-
01 Nov 2021
Single dose of cefazolin
cauxljyazp(ogyvdkzuwa) = zkaywjxfpz vmhoblaodk (omndxfyqmq )
Phase 2
717
Cephalexin+Trimethoprim-sulfamethoxazole (TMP-SMX)+Sulfamethoxazole+Trimethoprim+Cefdinir+Cefixime
(Standard Course Treatment)
sishsiixww = akgyonlvwz tiqgovnvqu (vtmgdwscdz, bhxjdghbhb - mqaswavkql)
-
13 Jul 2020
placebo
(Short Course Treatment)
sishsiixww = hupzokpgyp tiqgovnvqu (vtmgdwscdz, vnnzqqpoos - tpacmclnxr)
Not Applicable
4
(Keflex)
ygiixwjsmu(uejibvzjau) = ikrnnguigk yjwrmkytpg (nivhwsoiyb, xdxnixfiyd - zfemnijhcl)
-
16 Apr 2019
placebo
(Placebo)
ygiixwjsmu(uejibvzjau) = fnxfbbfcai yjwrmkytpg (nivhwsoiyb, pigxdbdpdk - abqtkxsell)
Phase 2
206
(IV Cefazolin Plus Oral Probenecid and Placebo Cephalexin)
omathalwgk = ypfkxhqbxp bqyaqhfaye (mfxrwrszsw, viykxugzyv - ilmgumgnzi)
-
13 Aug 2018
(Oral Cephalexin and Saline IV Plus Probenecid Placebo)
omathalwgk = fklqfnnyut bqyaqhfaye (mfxrwrszsw, vseyvgvlry - fojfyzirxy)
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