Cefalexin
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| Systematic (IUPAC) name | |
| (6R,7R)-7-{[(2R)-2-amino-2-phenylacetyl]amino}- 3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene- 2-carboxylic acid | |
| Clinical data | |
| AHFS/Drugs.com | monograph |
| Pregnancy cat. | A(AU) B(US) |
| Legal status | Prescription Only (S4) (AU) POM (UK) |
| Routes | Oral |
| Pharmacokinetic data | |
| Bioavailability | Well absorbed |
| Protein binding | 15% |
| Metabolism | 80% excreted unchanged in urine within 6 hours of administration |
| Half-life | For an adult with normal renal function, the serum half-life is 0.5-1.2 hours[1] |
| Excretion | Renal |
| Identifiers | |
| CAS number | 15686-71-2  |
| ATC code | J01DB01 QJ51DB01 |
| PubChem | CID 2666 |
| DrugBank | APRD00250 |
| ChemSpider | 25541 |
| UNII | 5SFF1W6677 |
| KEGG | D00263 |
| ChEBI | CHEBI:3534 |
| ChEMBL | CHEMBL1727 |
| Chemical data | |
| Formula | C16H17N3O4S |
| Mol. mass | 347.39 g/mol |
| SMILES | eMolecules & PubChem |
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Cefalexin (INN) or more commonly cephalexin (
/ˌsɛfəˈlɛksɨn/) is a first-generation cephalosporin antibiotic introduced in 1967 by Eli Lilly and Company.[2][3] It is an orally administered agent with a similar antimicrobial spectrum to the intravenous agents cefalotin and cefazolin. It was first marketed as Keflex (Lilly), and now is also sold under several other trade names.[2]
As of 2008, cefalexin was the most popular cephalosporin antibiotic in the United States, with more than 25 million prescriptions of its generic versions alone, for US$255 million in sales (though less popular than two other antibiotics, amoxicillin and azithromycin, each with 50 million prescriptions per year).[4][5]
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[edit] Medical uses
Cefalexin is used to treat a number of infections including: otitis media, streptococcal pharyngitis, bone and joint infections, pneumonia, cellulitis, and urinary tract infections.[6] It may be used to prevent bacterial endocarditis.[6]
[edit] Infections
In addition to being a rational first-line treatment for cellulitis, it is a useful alternative to penicillins in patients with penicillin hypersensitivity. In patients with mild or questionable history of penicillin allergy, cephalasporins are now thought to be relatively safe.[7] Caution should always be taken when prescribing cephalosporins to those with strong history of true penicillin hypersensitivity, however, because cefalexin and other first-generation cephalosporins are known to have a modest cross-allergy in patients with penicillin hypersensitivity.
Cefalexin may not be effective against bacteria that incorporate a gene for beta-lactamase on their R-plasmid as the beta-lactam ring is present in the chemical structure of cephalosporin derivatives.[citation needed]
[edit] Formulations
Cefalexin is marketed by generic pharmaceutical manufacturers under a wide range of brand names, including: Apo-Cephalex, Biocef, Cefanox, Ceforal, Cephabos, Cephalexin, Cephorum, Ceporex, Cilex, Ialex, Ibilex, Kefexin, Keflet, Keflex, Rekosporin, Keforal, Keftab, Keftal, Lopilexin, Larixin, Novo-Lexin, Ospexin, Tenkorex, Zephalexin, Panixine Disperdose, and Sporidex.
A version of Keflex 750 mg capsules is marketed for twice-daily dosage, to improve compliance. However, it is not a sustained release formulation, and since it is more expensive than the older strengths, some physicians prescribe three 250 mg capsules to be taken twice daily, as a cheaper alternative.[citation needed]
In Finland, cefalexin is marketed under several names. Orion markets Kefexin.[8][9]
[edit] Adverse effects
Common adverse effects include gastrointestinal upset such as diarrhea, nausea, vomiting, indigestion, and abdominal pain.[6] Others may include dizziness, agitation, headache, joint pain, and tiredness. The drug can also cause yellowing of the eyes or skin; red, blistered, swollen or peeling skin; unusual bruising or bleeding; decreased urination; severe cramps and confusion. An allergic reaction to this medicine is unlikely. Symptoms of an allergic reaction include rash, itching, swelling, or trouble breathing.
[edit] References
- ^ McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 95. Bethesda, MD: American Society of Hospital Pharmacists, Inc., 1995 (Plus Supplements 1995)., p. 166
- ^ a b Sweetman, Sean C., ed. (2009). "Antibacterials". Martindale: The complete drug reference (36th ed.). London: Pharmaceutical Press. pp. 218–9. ISBN 978-0-85369-840-1.
- ^ Sneader, Walter (2005). "Cephalosporin analogues". Drug discovery: a history. New York: Wiley. pp. 324. ISBN 0-471-89980-1. http://books.google.com/books?id=mYQxRY9umjcC&pg=PA324. Retrieved 2009-06-26.
- ^ "2008 Top 200 generic drugs by total prescriptions" PDF (332.8 KB). Drug Topics (May 26, 2009). Retrieved on July 24, 2009.
- ^ "2008 Top 200 generic drugs by retail dollars" PDF (399.4 KB). Drug Topics (May 26, 2009). Retrieved on July 24, 2009.
- ^ a b c "Cephalexin". The American Society of Health-System Pharmacists. http://www.drugs.com/monograph/cephalexin.html. Retrieved 3 April 2011.
- ^ Pichichero ME (March 2007). "Use of selected cephalosporins in penicillin-allergic patients: a paradigm shift". Diagnostic Microbiology and Infectious Disease 57 (3 Suppl): 13S–18S. doi:10.1016/j.diagmicrobio.2006.12.004. PMID 17349459.
- ^ http://spc.nam.fi/indox/nam/html/nam/humpil/2/244412.pdf.
- ^ http://spc.nam.fi/indox/nam/html/nam/humspc/2/244362.shtml.
[edit] External links
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