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Cefalexin
Sub-sections

Cefalexin

Cefalexin Hydrochloride

Adverse Effects and Precautions

Interactions

Antimicrobial Action

Pharmacokinetics
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Uses and Administration

Preparations
Cefalexin
Date of monograph review: 24-Mar-1997; 20-Jul-1998; 06-Oct-1999; 02Oct-2001; 12-Nov-2003; 28-May-2004; 25-Jul-2006; 10-Sep-2008; 20-Nov2009; 20-Aug-2010; (latest modification: 30-Jan-2013)
Drug Nomenclature (Latest modification: 30-Jan-2013)
Synonyms: 66873; Κεφαλεξίνη; Cefaleksinas monohidratas;
Cefaleksyna; Cefalexin monohydrát; Cefalexina; Céfalexine
monohydratée; Cefalexinmonohydrat; Cefalexinum; Cefalexinum
Monohydricum; Cephalexin; Kefaleksiini; Kefaleksiinimonohydraatti;
Sefaleksin; セファレキシン
BAN: Cefalexin
USAN: Cephalexin
INN: Cefalexin [pINN (en)]
INN: Cefalexina [pINN (es)]
INN: Céfalexine [pINN (fr)]
INN: Cefalexinum [pINN (la)]
INN: Цефалексин [pINN (ru)]
INN: ‫[ ال ي ك س ين س يف‬pINN (ar)]
INN: 头孢氨苄 [pINN (cn)]
Chemical name: (7R)-3-Methyl-7-(α-D-phenylglycylamino)-3-cephem4-carboxylic acid monohydrate
Molecular formula: C16H17N3O4S,H2O =365.4
CAS: 15686-71-2 (anhydrous cefalexin); 23325-78-2 (cefalexin
monohydrate)
ATC code: J01DB01
ATC code (veterinary): QJ01DB01; QJ51DA01
UNII code: OBN7UDS42Y (cefalexin); 5SFF1W6677 (anhydrous
cefalexin)
Chemical Structure of Cefalexin
Pharmacopoeias:
In Chin., Eur. (see
), Jpn, US, and Viet.
Ph. Eur. 7 (Cefalexin Monohydrate). A white or almost white crystalline
powder. Sparingly soluble in water; practically insoluble in alcohol. A
0.5% solution in water has a pH of 4.0 to 5.5. Protect from light.
USP 36 (Cephalexin). A white to off-white crystalline powder. Slightly
soluble in water; practically insoluble in alcohol, in chloroform, and in
ether. pH of a 5% suspension in water is between 3.0 and 5.5. Store in
airtight containers.
Cefalexin Hydrochloride
Date of monograph review: 24-Mar-1997; 20-Jul-1998; 06-Oct-1999; 02Oct-2001; 12-Nov-2003; 28-May-2004; 25-Jul-2006; 10-Sep-2008; 20-Nov2009; 20-Aug-2010; (latest modification: 30-Jan-2013)
Drug Nomenclature (Latest modification: 30-Jan-2013)
Synonyms: Cefalexina, hidrocloruro de; Cephalexin Hydrochloride; LY061188; 塩酸セファレキシン
BAN: Cefalexin Hydrochloride [BANM]
USAN: Cephalexin Hydrochloride
INN: Cefalexin Hydrochloride [pINNM (en)]
INN: Hidrocloruro de cefalexina [pINNM (es)]
INN: Céfalexine, Chlorhydrate de [pINNM (fr)]
INN: Cefalexini Hydrochloridum [pINNM (la)]
INN: Цефалексина Гидрохлорид [pINNM (ru)]
Molecular formula: C16H17N3O4S,HCl,H2O =401.9
CAS: 105879-42-3
ATC code: J01DB01
ATC code (veterinary): QJ01DB01
UNII code: 6VJE5G3D98
Pharmacopoeias:
In US.
USP 36 (Cephalexin Hydrochloride). A white to off-white crystalline
powder. Soluble 1 in 100 in water, in acetone, in acetonitrile, in alcohol,
in dimethylformamide, and in methyl alcohol; practically insoluble in
chloroform, in ether, in ethyl acetate, and in isopropyl alcohol. pH of a
1% solution in water is between 1.5 and 3.0. Store in airtight containers.
Adverse Effects and Precautions (Latest modification: 25-Mar-2004)
As for Cefalotin Sodium,
.
The most common adverse effects of cefalexin and other oral cephalosporins
are generally gastrointestinal disturbances and hypersensitivity reactions.
Pseudomembranous colitis has been reported.
(last reviewed 2010-08-20; last modified 2004-03-25)
References.
(last reviewed 2010-08-20; last modified 2009-09-05)
1. 1. Dave J, et al. Cephalexin induced toxic epidermal necrolysis. J
Antimicrob Chemother 1991; 28: 477–8. PubMed
2. 2. Baran R, Perrin C. Fixed-drug eruption presenting as an acute
paronychia. Br J Dermatol 1991; 125: 592–5. PubMed
3. 3. Clark RF. Crystalluria following cephalexin overdose. Pediatrics 1992;
89: 672–4. PubMed
4. 4. Murray KM, Camp MS. Cephalexin-induced Stevens-Johnson syndrome.
Ann Pharmacother 1992; 26: 1230–3. PubMed
5. 5. Czechowicz RT, et al. Bullous pemphigoid induced by cephalexin.
Australas J Dermatol 2001; 42: 132–5. PubMed
6. 6. Longstreth KL, et al. Cephalexin-induced acute tubular necrosis.
Pharmacotherapy 2004; 24: 808–11. PubMed
7. 7. Skoog SM, et al. Cephalexin-induced cholestatic hepatitis. J Clin
Gastroenterol 2004; 38: 833. PubMed
8. 8. Chan AL, et al. Fatal anaphylactic reaction to intravenous cephalexin.
Clin Drug Invest 2005; 25: 675–8. PubMed
9. 9. Penttilä J, et al. Delirium in an adolescent patient during treatment with
cephalexin. J Adolesc Health 2006; 39: 782–3. PubMed
Porphyria (Latest modification: 01-Nov-2011)
The Drug Database for Acute Porphyria, compiled by the Norwegian
Porphyria Centre (NAPOS) and the Porphyria Centre Sweden, classifies
cefalexin as probably not porphyrinogenic; it may be used as a drug of
first choice and no precautions are needed.1
(last reviewed 2010-08-20; last modified 2011-11-01)
1. 1. The Drug Database for Acute Porphyria. Available at: online (accessed
18/10/11)
Interactions (Latest modification: 27-Aug-2009)
The renal excretion of cefalexin, and many other cephalosporins, is delayed
by probenecid.
(last reviewed 2010-08-20; last modified 2009-08-27)
Hormonal contraceptives (Latest modification: 04-May-2011)
There have been isolated reports of cefalexin decreasing the efficacy of
oestrogen-containing oral contraceptives.1 However, evidence does not
generally support an interaction between broad-spectrum antibacterials
and hormonal contraceptives (see
).
(last reviewed 2010-08-20; last modified 2011-05-04)
1. 1. Friedman M, et al. Cephalexin and Microgynon-30 do not go well
together. J Obstet Gynaecol 1982; 2: 195–6.
Antimicrobial Action (Latest modification: 25-Mar-2004)
As for Cefalotin Sodium,
, although cefalexin is generally less potent.
Some strains of Gram-negative bacteria may be inhibited only by the high
concentrations achievable in the urinary tract. Haemophilus influenzae is
moderately resistant to cefalexin.
(last reviewed 2010-08-20; last modified 2004-03-25)
Pharmacokinetics (Latest modification: 27-Jul-2010)
Cefalexin is almost completely absorbed from the gastrointestinal tract and a
peak plasma concentration of about 18 micrograms/mL occurs 1 hour after a
500-mg oral dose. If cefalexin is taken with food, absorption may be
delayed, but the total amount absorbed is not appreciably altered. Up to
15% of a dose is bound to plasma proteins. The plasma half-life is about 1
hour; it increases with reduced renal function.
Cefalexin is widely distributed in the body but does not enter the CSF in
significant quantities. It crosses the placenta and small quantities are found
in breast milk. Cefalexin is not metabolised. About 80% or more of a dose is
excreted unchanged in the urine in the first 6 hours by glomerular filtration
and tubular secretion; urinary concentrations greater than 1 mg/mL have
been achieved after a dose of 500 mg. Probenecid delays urinary excretion.
Therapeutically effective concentrations may be found in the bile and some
may be excreted by this route.
Cefalexin is removed by haemodialysis and peritoneal dialysis.
(last reviewed 2010-08-20; last modified 2010-07-27)
References.
(last reviewed 2010-08-20; last modified 2004-03-25)
1. 1. Wise R. The pharmacokinetics of the oral cephalosporins—a review. J
Antimicrob Chemother 1990; 26 (suppl E): 13–20. PubMed
Uses and Administration (Latest modification: 04-Aug-2010)
Cefalexin is a first-generation oral cephalosporin antibacterial for the
treatment of infections caused by susceptible Gram-positive and Gramnegative bacteria including infections of the respiratory and genito-urinary
tracts, bones, and skin. For details of these infections and their treatment,
see under Choice of Antibacterial,
.
Cefalexin is usually given as the monohydrate although the hydrochloride is
sometimes used. Doses are expressed in terms of the equivalent amount of
anhydrous cefalexin; 1.05 g of cefalexin monohydrate and 1.16 g of
cefalexin hydrochloride are each equivalent to about 1 g of anhydrous
cefalexin.
It is given in doses ranging from 1 to 4 g daily in divided doses; 250 to
500 mg every 6 to 8 hours is typical. For skin and soft tissue infections,
streptococcal pharyngitis, and uncomplicated urinary-tract infections a dose
of 250 mg every 6 hours or 500 mg every 12 hours may be given. If daily
doses greater than 4 g are needed, parenteral cephalosporins should be
considered.
For the prophylaxis of recurrent urinary-tract infection, cefalexin may be
given in a dose of 125 mg at night.
For details of doses in children, see
.
The dose of cefalexin may need to be reduced in renal impairment, see
.
Cefalexin sodium or cefalexin lysine have been used parenterally.
(last reviewed 2010-08-20; last modified 2010-08-04)
Administration in children (Latest modification: 04-Aug-2010)
Cefalexin may be given orally to children for the treatment of infections
caused by susceptible Gram-positive and Gram-negative bacteria. The
usual recommended dose is 25 to 50 mg/kg daily in 2 or 3 divided doses.
In severe infections the dose may be doubled and for otitis media a dose
of 75 to 100 mg/kg daily in 4 divided doses is recommended.
Alternative doses recommended by the BNFC 2010/11 are:
children over 1 month of age: 12.5 mg/kg twice daily; dose should be
doubled in severe infection (to a maximum dose of 1 g 4 times daily) or
children 1 month to 1 year of age: 125 mg twice daily
children 1 to 5 years of age: 125 mg 3 times daily
children more than 5 years of age: 250 mg 3 times daily
Although not licensed in the UK for neonates, the BNFC 2010/11 suggests
a dose of 25 mg/kg (to a maximum of 125 mg) may be given twice daily
for neonates less than 7 days old, 3 times daily for those aged 7 to 21
days, and 4 times daily for those aged 21 to 28 days.
For the prophylaxis of recurrent urinary-tract infection the BNFC 2010/11
recommends that children over 1 month of age be given 12.5 mg/kg orally
at night (to a maximum dose of 125 mg).
(last reviewed 2010-08-20; last modified 2010-08-04)
Administration in renal impairment (Latest modification: 16-Aug-2010)
Oral doses of cefalexin may need to be reduced in patients with renal
impairment. The BNF 59 recommends the following maximum daily doses
according to creatinine clearance (CC):
CC 40 to 50 mL/minute per 1.73 m2: maximum 3 g daily
CC 10 to 40 mL/minute per 1.73 m2: maximum 1.5 g daily
CC less than 10 mL/minute per 1.73 m2: maximum 750 mg daily
(last reviewed 2010-08-20; last modified 2010-08-16)
Preparations (Latest modification: 01-Jul-2013)
Single-ingredient Preparations (Latest modification: 01-Jul-2013)
The symbol ¤ denotes a preparation which is discontinued or no longer
actively marketed.
Argentina: Beliam; Butefina¤; Cefagrand; Cefalexi¤; Cefapoten¤;
Cefarinol¤; Cefasporina; Cefosporen; Ceporexin Duo; Ceporexin; Fabotop;
Keforal; Lafexina; Lars; Lexin; Lorbicefax; Novalexin¤; Ospexin; Pectorina¤;
Permvastat; Sanibiotic; Septilisin Duo; Septilisin; Trexina; Triblix; Velexina;
Australia: Ceflin¤; Cephatrust; Ceporex¤; Cilex; Ialex; Ibilex; Keflex;
Rancef; Sporahexal¤; Austria: Cepexin¤; Cephalobene; Keflex; Ospexin;
Sanaxin; Belgium: Ceporex¤; Keforal; Brazil: Betacef¤; Cefaben;
Cefacimed; Cefagel; Cefagon¤; Cefagran; Cefalen¤; Cefalexan¤; Cefalexol;
Cefanal; Cefanid; Cefaporex¤; Cefaxon; Cefexina; Ceflexin¤; Celen¤;
Celexin¤; Celinax¤; Ceporexin¤; Falexin¤; Kefalexin¤; Keflaxina; Keflex;
Keforal¤; Kiflexin¤; Lexin; Lifalexin¤; Neo Ceflex; Neoceflex; Primacef;
Profalexina¤; Todexin¤; Valflex; Canada: Apo-Cephalex; Ceporex¤; Keflex;
Novo-Lexin; Nu-Cephalex; China: Bei Dun; Fulin; Meifeng; Shen Jia;
Sporidex; Czech Republic: Cefaclen¤; Oracef¤; Ospexin¤; Sporidex¤;
Denmark: Keflex; Finland: Kefalex; Kefexin; Orakef¤; France: Cefacet;
Ceporexine¤; Keforal; Germany: Cephalex; Ceporexin¤; Oracef¤; Greece:
Kefalospes; Kefaxin; Keflex; Keflogen; Kekrinal; Medalexine; Neptolin;
Nylichlor; Sinthecillin; Tricylamil; Zabytrex; Hong Kong: Anxer¤; ApoCepalex¤; Apo-Cephalex¤; Cefacapxin¤; Cefacin; Cefacure¤; Cephalexyl¤;
Cephin¤; Ceporex¤; Felexin; Keflex¤; Medolexin; Ora-C¤; Ospexin; Sofilex;
Solulexin¤; Syntolexin¤; Hungary: Keflex¤; Pyassan; Servispor¤; India:
Alcephin; Alexin; Allsafe; Anphexin; Axin-LA; Bactocep; Betaspore; Biolex;
Blucef; C-Lex; Cefacin; Cefact; Cefacure; Cefalex; Cefalin; Cefamax; Cefax;
Cefbact; Cefcidal; Cefel; Ceff; Cefmix; Ceftop RM; Celexin; Cephadex;
Cephal; Cephalex; Cephalkem; Cephalpet; Cephamax; Cepharil; Cephaxin;
Cephaxtar; Cexin; Ciphlenat; Citaceph; Cucef; Culexin; DT LX-Kid; E CefOD; Emceph; Equitrol; Faxe; Fex; Gencef; Gexin; Halexin; Hycef; Keflex;
Lecef; Lexa; Lexillin; Lexipil; LX; Mepycep; Mexef; Monacef; Neocef; Niphex;
Nufex; Oralex; Oriphex; Phexin; Rofex; Sepexin; Sporidex; Indonesia:
Cefabiotic; Madlexin; Ospexin; Pralexin¤; Sofaxin; Tepaxin; Theralexin¤;
Ireland: Ceporex¤; Kefexin¤; Keflex; Israel: Cefalin¤; Ceforal; Cefovit;
Keflex¤; Italy: Abiocef¤; Cefadros¤; Cepo¤; Ceporex; Coliceflor¤;
Domucef¤; Ibilex¤; Keforal; Lafarin¤; Latoral¤; Lorexina¤; Sintolexyn¤;
Zetacef-lis¤; Zetacef¤; Japan: Larixin; Malaysia: Cefax¤; Celexin¤;
Cephanmycin; Ceporex¤; Felexin; Kefexin¤; Medolexin; Ospexin; Refex¤;
Sofilex; Solulexin; Sporidex; Uphalexin; Mexico: Acacin¤; Ancetev¤;
Arlexen; Capxin; Cefalver; Ceporex; Facelit¤; Falexol¤; Fleximin¤; Flextinol;
Keflex; Meta-K¤; Nafacil; Naxifelar; Nixelaf-C; Optocef; Paferxin;
Quimosporina; Servicef; Sporicef; Netherlands: Ceporex¤; Keforal;
Norway: Keflex; New Zealand: Keflex¤; Philippines: Airex; Bacilexin;
Bandax; Benlexin; Bloflex; Canelin; Cefalin; Cendalex; Ceporex; CFA;
Civalex; Clephin¤; Difalex; Edexin; Eliphorin; Exel; Fablex; Falex; Falteria;
Forexine; Halcepin¤; Infexin; Ivynall; Keflex¤; Lewimycin; Lexum; Lonarel¤;
Lyceplix; Madexin; Medilexin; Medoxine; Mefolex; Mexin; Montralex¤;
Nefadon; Neolecsin; Nerfalex; Oneflex; Pediaflex; Respinal; Selzef;
Servispor¤; Sorlex; Sporidex¤; Xeface; Xinflex; Zepharyl; Zeporin; Zepotex;
Zexanta¤; Zinace; Zucoflaxin¤; Poland: Keflex; Portugal: Ceflax¤;
Ceporex¤; Keflex¤; South Africa: Belex; Betacef¤; Ceporex¤; Cerexin¤;
Fexin¤; Keflex; Lenocef¤; Ranceph; Singapore: Apo-Cephalex; Celexin;
Cephalen¤; Cephanmycin; Ceporex; Felexin; Ospexin; Sofilex; Solulexin;
Sporidex; Uphalexin; Spain: Bioporina¤; Bioscefal¤; Cefadina¤; Cefaleh
Ina¤; Cefalexgobens; Cefalival¤; Cefalorex¤; Cefamiso¤; Ceferran¤;
Cefibacter¤; Ceporex¤; Cilicef¤; Defaxina¤; Efemida¤; Erifalecin¤; Fergon¤;
Janocilin¤; Karilexina¤; Kefloridina; Lensafrend¤; Lerporina¤; Lexibiotico¤;
Lexincef¤; Libesporal¤; Sporol¤; Sulquipen; Talinsul¤; Torlasporin¤;
Ultralexin¤; Valesporin¤; Sweden: Keflex; Switzerland: Ceporex¤;
Keflex¤; Servispor¤; Thailand: Anxer¤; Cefexin¤; Cefute; Cefxin¤; Celex;
Celexin¤; Cephalexyl; Cephin; Ceporex¤; Farmalex; Felexin; Ibilex; Keflex;
Mycef; Neolexin¤; Pondnacef¤; Sefasin¤; Servispor¤; Sialexin; Sporicef;
Sporidex¤; Sporidin; Suphalex; Teplexin; Toflex; Ulflex; Vataceph¤; Zeplex;
Turkey: Maksipor; Sef; United Arab Emirates: Cefrin; United Kingdom:
Ceporex; Keflex-C¤; Keflex; Kiflone¤; Ukraine: Lexin (Лексин); Ospexin
(Оспексин)¤; United States: Biocef¤; Cefanex; Keflet¤; Keflex; Keftab¤;
Zartan¤; Venezuela: Bidocef; Cefaloga¤; Keforal; Stricef;
Multi-ingredient Preparations (Latest modification: 25-Jan-2012)
The symbol ¤ denotes a preparation which is discontinued or no longer
actively marketed.
China: Pixian; Xindabao; India: Alcephin-LA; Caceff; Carbicef; Cecarb;
Cefalong-DS; Cefel-B; Ceff-LA; Cep-Bro; Cephadex LB; Italy: Foce¤;
Fosfolexin¤; Kufaprim¤; Mexico: Arlexen B; Cefabroxil; Cepobrom;
Mucocef; Rombox; Spain: Kefloridina Mucolitico¤; Mucobiotina¤; Prindex
Mucolitico¤;
Pharmacopoeial Preparations (Latest modification: 06-Dec-2011)
BP 2013: Cefalexin Capsules; Cefalexin Oral Suspension; Cefalexin Tablets;
USP 36: Cephalexin Capsules; Cephalexin for Oral Suspension; Cephalexin
Tablets for Oral Suspension; Cephalexin Tablets;
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