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a semisynthetic, first-generation cephalosporin antibiotic, effective against a wide range of gram-positive and a limited number of gram-negative bacteria; administered orally as the base or the hydrochloride salt in the treatment of tonsillitis, otitis media, and infections of the genitourinary tract, of bones and joints, and of skin and soft tissues.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Apo-Cephalex, Biocef, Dom-Cephalexin, Keflex, Novo-Lexin, Nu-Cephalex, Panixine DisperDose, PMS-Cephalexin

Pharmacologic class: First-generation cephalosporin

Therapeutic class: Anti-infective

Pregnancy risk category B


Interferes with bacterial cell-wall synthesis, causing cell to rupture and die. Active against many gram-positive bacteria; shows limited activity against gram-negative bacteria.


Capsules: 250 mg, 500 mg, 750 mg

Oral suspension: 125 mg/5 ml, 250 mg/5 ml

Tablets: 250 mg, 500 mg

Indications and dosages

Respiratory tract infections caused by streptococci; skin and skin-structure infections caused by methicillin-sensitive staphylococci and streptococci; bone infections caused by methicillin-sensitive staphylococci or Proteus mirabilis; genitourinary infections caused by Escherichia coli, P. mirabilis, and Klebsiella species; Haemophilus influenzae, methicillin-sensitive staphylococcal, streptococcal, and Moraxella catarrhalis infections
Adults: 1 to 4 g P.O. daily in divided doses (usually 250 mg P.O. q 6 hours). For uncomplicated cystitis, skin and soft-tissue infections, and streptococcal pharyngitis, 500 mg P.O. q 12 hours.
Children: 25 to 50 mg/kg/day P.O. in divided doses

Otitis media caused by S. pneumoniae
Children: 75 to 100 mg/kg/day P.O. in four divided doses

Dosage adjustment

• Renal impairment


• Hypersensitivity to cephalosporins or penicillin


Use cautiously in:

• renal impairment, phenylketonuria

• history of GI disease

• debilitated or emaciated patients

• elderly patients

• pregnant or breastfeeding patients.


• Give with or without food.

• Refrigerate oral suspension.

Adverse reactions

CNS: fever, headache, lethargy, paresthesia, syncope, seizures

CV: edema, hypotension, vasodilation, palpitations, chest pain

EENT: hearing loss

GI: nausea, vomiting, diarrhea, abdominal cramps, oral candidiasis, pseudomembranous colitis

GU: vaginal candidiasis, nephrotoxicity

Hematologic: lymphocytosis, eosinophilia, bleeding tendency, hemolytic anemia, neutropenia, thrombocytopenia, agranulocytosis, bone marrow depression

Musculoskeletal: joint pain

Respiratory: dyspnea

Skin: rash, maculopapular and erythematous urticaria

Other: superinfection, chills, pain, allergic reaction, hypersensitivity reactions including anaphylaxis, serum sickness


Drug-drug. Aminoglycosides, loop diuretics: increased risk of nephrotoxicity

Chloramphenicol: antagonistic effect

Probenecid: increased cephalexin blood level

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine, eosinophils, lactate dehydrogenase, lymphocytes: increased values
Coombs' test: false-positive result (especially in neonates whose mothers received drug before delivery)

Granulocytes, neutrophils, white blood cells: decreased counts

Patient monitoring

• Assess for signs and symptoms of serious adverse reactions, including hypersensitivity, severe diarrhea, and bleeding.

• During long-term therapy, monitor CBC and liver and kidney function test results.

Patient teaching

Instruct patient to stop taking drug and contact prescriber immediately if he develops rash or difficulty breathing.

• Tell patient to take drug with full glass of water.

• Advise patient to report severe diarrhea.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


A semisynthetic cephalosporin antibiotic, C16H17N3O4S, used especially in the treatment of respiratory and urinary tract infections.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Keflex® Infectious disease A 3rd generation broad-spectrum cephalosporin
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


Cefalexin, a CEPHALOSPORIN antibiotic effective by mouth. Brand names are Ceporex and Keflex.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
Except for Nitrofurantoin and Ciprofloxacin that are not appropriate options for UTI treatment in children [19], the highest percentages of susceptibility were seen for Amikacin (79.7%), Ofloxacin (78.3%), and Gentamicin (71.6%), whereas the highest percentages of resistance for this pathogen were found for Ampicillin (83.5%), Cotrimoxazol (75.4%), and Cefalexin (69.8%).
Resistant Intermediate Sensitive Nitrofurantoin 9/6 0/9 89/4 Ciprofloxacin 20/8 2/3 76/9 Ofloxacin 19/6 2/2 78/3 Nalidixic acid 49/8 1/6 48/7 Amikacin 19/4 1 79/7 Gentamicin 27/9 0/4 71/6 Tobramycin 60/4 39/6 Ceftazidime 37 3/7 59/6 Cefotaxime 56/2 2/4 41/6 Cefriaxone 52/2 6 41/8 Cefixime 68/4 3/8 27/8 Cefazolin 67/1 32/9 Cefalexin 69/8 3 27/2 Cotrimoxasole 75/4 1/9 22/7 Ampicillin 83/5 4/5 12 Note: Table made from bar graph.
In hospital 1, the drug that was widely used for respiratory diseases (LRTI, URTI) and fever was amoxicillin followed by cefalexin and cefixime.
Antimicrobial % sensibility/ Risk of bacterial resistance % resistance RAP CI 95% Value P Penicillin 0/100 Reference Reference NA Amoxicillin 17/83 0,049 0,01-0,38 <0,004 Ampicillin 0/100 1,0 0,06-16,21 >0,1 Cefalexin 25/75 0,03 0,004-0,23 <0,001 Cloranfenicol 85/15 0,002 0,001-0,01 <0,0001 Doxiciclin 50/50 0,01 0,001-0,07 <0,0001 Enrofloxacin 75/25 0,003 0,001-0,02 <0,0001 Florfenicol 67/33 0,005 0,001-0,04 <0,0001 Gentamicin 75/25 0,003 0,001-0,02 <0,0001 Neomicin 0/100 1,0 0,06-16,21 >0,1 Norfloxacin 50/50 0,01 0,001-0,07 <0,0001 Tetraciclin 50/50 0,01 0,001-0,07 <0,0001 RAP: Ratio of adjusted proportions; CI 95%: Confidence interval 95% probability; NA: Not Applicable.
The duties, agreed without discussion at the EU's General Affairs Council, apply to three semi-synthetic penicillins: amoxicillin trihydrate, ampicillin trihydrate and cefalexin. They are virtually the same as the duties set provisionally by the Commission last May, and include a lower duties like 9.6% for Biochem Synergy, 4.6% for Lupin and zero duties for Torrent Pharmaceutical, Vitara Chemical and Gujarat Lyka Organics.
A total of 10 antibiotic discs--Ampicillin (A-10 mcg,) Amoxycillin (Am-30mcg), Cefalexin (Cn 30mcg), Norfloxacin (Nx-10mcg), Chloramphenicol (C-30 mcg), Ceftriaxone (Ctr--30mcg), Azithromycin (Azm- 30 mcg), Ciprofloxacin (Cip- 1 mcg), Ampicilin-Cloxacilin (Ax- 10 mcg) and Erythromycin (E-30 mcg) supplied by Hi-Media laboratories were used in the present study.
Empirical antibiotic which can be selected for oral administration include amoxycillin clavulanate, TMP-SMX, cefixime, sefpodoxim, cefprozil, cefuroxime axetil and cefalexin. Emprical parenteral treatment options include ceftriaxon, cefotaxim, ceftazidim, gentamycin, tobramycin and piperacillin (12).
If an additional infectious process is suspected, due to the slow evolution of the dermonecrotic process, this makes it inclined to Gram positive microorganisms (streptococci and staphylococci) attraction, considering the use of cloxacylin, flucloxacylin, cefalexin, oral penicillin or clindamycin necessary.
Microorganism types found in urine culture of the myelodysplastic patients by the state of use of prophylactic antibiotic and antibiotic resistance properties Use of prop hylactic antibiotic Yes No n (%) n (%) p (*) Patient number 60 (84.5) 11 (15.5) Prophylactic antibiotic types Co-trimoxazol 38 (63.3) - Nitrofurantoin 10 (16.7) - Cefalexin 6 (10) - Cefaklor 6 (10) - Microorganism types found in UC E.