Search The Medical Knowledge Base

Drug Details

Keflex tablets, Capsules and Granules

• Drug Class Description
  Cephalosporins.
• Generic Name
  Cefalexin [cephalexin]
• Presentation
  Keflex Capsules: Cefalexin monohydrate 250 mg . Keflex Tablets: Cefalexin monohydrate 250 mg . Keflex Suspension: Cefalexin monohydrate 125 mg , 250 mg per 5 mL.
• Description
  Keflex tablets. Keflex capsules. Keflex Granules for Oral Suspension BP.
• Indications
  

  Cefalexin is a semi-synthetic cephalosporin antibiotic for oral administration.

  Cefalexin is indicated in the treatment of the following infections due to susceptible micro-organisms:

  Respiratory tract infections

  Otitis media

  Skin and soft tissue infections

  Bone and joint infections

  Genito-urinary tract infections, including acute prostatitis

  Dental infections

• Adult Dosage
  

   

  Cefalexin is administered orally.

  The bottle is first inverted and tapped to loosen the powder then a total of 60ml water in two portions is added, shaking after each addition until suspended. If dilution is unavoidable, Syrup BP should be used after the suspension has been prepared as described. Shake well before use.

  Adults: The adult dosage ranges from 1-4g daily in divided doses; most infections will respond to a dosage of 500mg every 8 hours. For skin and soft tissue infections, streptococcal pharyngitis, and mild, uncomplicated urinary tract infections, the usual dosage is 250mg every 6 hours, or 500mg every 12 hours.

  For more severe infections or those caused by less susceptible organisms, larger doses may be needed. If daily doses of cefalexin greater than 4g are required, parenteral cephalosporins, in appropriate doses, should be considered.

  The elderly and patients with impaired renal function: As for adults. Reduce dosage if renal function is markedly impaired.

  Children: The usual recommended daily dosage for children is 25-50mg/kg (10-20mg/lb) in divided doses. For skin and soft tissue infections, streptococcal pharyngitis, and mild, uncomplicated urinary tract infections, the total daily dose may be divided and administered every 12 hours. For most infections the following schedule is suggested:

  Children under 5 years: 125mg every 8 hours.

  Children 5 years and over: 250mg every 8 hours.

  In severe infections, the dosage may be doubled. In the therapy of otitis media, clinical studies have shown that a dosage of 75 to 100mg/kg/day in 4 divided doses is required.

  In the treatment of beta-haemolytic streptococcal infections, a therapeutic dose should be administered for at least 10 days.

   

• Child Dosage
  

   

  Cefalexin is administered orally.

  The bottle is first inverted and tapped to loosen the powder then a total of 60ml water in two portions is added, shaking after each addition until suspended. If dilution is unavoidable, Syrup BP should be used after the suspension has been prepared as described. Shake well before use.

  Adults: The adult dosage ranges from 1-4g daily in divided doses; most infections will respond to a dosage of 500mg every 8 hours. For skin and soft tissue infections, streptococcal pharyngitis, and mild, uncomplicated urinary tract infections, the usual dosage is 250mg every 6 hours, or 500mg every 12 hours.

  For more severe infections or those caused by less susceptible organisms, larger doses may be needed. If daily doses of cefalexin greater than 4g are required, parenteral cephalosporins, in appropriate doses, should be considered.

  The elderly and patients with impaired renal function: As for adults. Reduce dosage if renal function is markedly impaired.

  Children: The usual recommended daily dosage for children is 25-50mg/kg (10-20mg/lb) in divided doses. For skin and soft tissue infections, streptococcal pharyngitis, and mild, uncomplicated urinary tract infections, the total daily dose may be divided and administered every 12 hours. For most infections the following schedule is suggested:

  Children under 5 years: 125mg every 8 hours.

  Children 5 years and over: 250mg every 8 hours.

  In severe infections, the dosage may be doubled. In the therapy of otitis media, clinical studies have shown that a dosage of 75 to 100mg/kg/day in 4 divided doses is required.

  In the treatment of beta-haemolytic streptococcal infections, a therapeutic dose should be administered for at least 10 days.

   

• Elderly Dosage
  

   

  Cefalexin is administered orally.

  The bottle is first inverted and tapped to loosen the powder then a total of 60ml water in two portions is added, shaking after each addition until suspended. If dilution is unavoidable, Syrup BP should be used after the suspension has been prepared as described. Shake well before use.

  Adults: The adult dosage ranges from 1-4g daily in divided doses; most infections will respond to a dosage of 500mg every 8 hours. For skin and soft tissue infections, streptococcal pharyngitis, and mild, uncomplicated urinary tract infections, the usual dosage is 250mg every 6 hours, or 500mg every 12 hours.

  For more severe infections or those caused by less susceptible organisms, larger doses may be needed. If daily doses of cefalexin greater than 4g are required, parenteral cephalosporins, in appropriate doses, should be considered.

  The elderly and patients with impaired renal function: As for adults. Reduce dosage if renal function is markedly impaired.

  Children: The usual recommended daily dosage for children is 25-50mg/kg (10-20mg/lb) in divided doses. For skin and soft tissue infections, streptococcal pharyngitis, and mild, uncomplicated urinary tract infections, the total daily dose may be divided and administered every 12 hours. For most infections the following schedule is suggested:

  Children under 5 years: 125mg every 8 hours.

  Children 5 years and over: 250mg every 8 hours.

  In severe infections, the dosage may be doubled. In the therapy of otitis media, clinical studies have shown that a dosage of 75 to 100mg/kg/day in 4 divided doses is required.

  In the treatment of beta-haemolytic streptococcal infections, a therapeutic dose should be administered for at least 10 days.

   

• Contra Indications
  

  Cefalexin is contra-indicated in patients with known allergy to the cephalosporin group of antibiotics.

• Special Precautions
  

  Before instituting therapy with cefalexin, every effort should be made to determine whether the patient has had previous hypersensitivity reactions to the cephalosporins, penicillins, or other drugs. Cefalexin should be given cautiously to penicillin-sensitive patients. There is some clinical and laboratory evidence of partial cross-allergenicity of the penicillins and cephalosporins. Patients have had severe reactions (including anaphylaxis) to both drugs.

  Pseudomembranous colitis has been reported with virtually all broad-spectrum antibiotics, including macrolides, semi-synthetic penicillins, and cephalosporins. It is important, therefore, to consider its diagnosis in patients who develop diarrhoea in association with the use of antibiotics. Such colitis may range in severity from mild to life-threatening. Mild cases of pseudomembranous colitis usually respond to drug discontinuance alone. In moderate to severe cases, appropriate measures should be taken.

  If an allergic reaction to cefalexin occurs, the drug should be discontinued and the patient treated with the appropriate agents.

  Prolonged use of cefalexin may result in the overgrowth of non-susceptible organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, appropriate measures should be taken.

  Cefalexin should be administered with caution in the presence of markedly impaired renal function. Careful clinical and laboratory studies should be made because safe dosage may be lower than that usually recommended.

  Positive direct Coombs' tests have been reported during treatment with the cephalosporin antibiotics. In haematological studies, or in transfusion cross-matching procedures when antiglobulin tests are performed on the minor side, or in Coombs' testing of newborns whose mothers have received cephalosporin antibiotics before parturition, it should be recognised that a positive Coombs' test may be due to the drug.

  A false positive reaction for glucose in the urine may occur with Benedict's or Fehling's solutions, or with copper sulphate test tablets.

• Interactions
  

   

  As with other beta-lactam drugs, renal excretion of cefalexin is inhibited by probenecid.

  In a single study of 12 healthy subjects given single 500mg doses of cefalexin and metformin, plasma metformin C_maxand AUC increased by an average of 34% and 24%, respectively, and metformin renal clearance decreased by an average of 14%. No side-effects were reported in the 12 healthy subjects in this study. No information is available about the interaction of cefalexin and metformin following multiple dose administration. The clinical significance of this study is unclear, particularly as no cases of “lactic acidosis” have been reported in association with concomitant metformin and cefalexin treatment.

  Hypokalaemia has been described in patient taking cytotoxic drugs for leukaemia when they were given gentamicin and cephalexin.

   

• Adverse Drug Reactions
  

  Gastro-intestinal: Symptoms of pseudomembranous colitis may appear either during or after antibiotic treatment. Nausea and vomiting have been reported rarely. The most frequent side-effect has been diarrhoea. It was very rarely severe enough to warrant cessation of therapy. Dyspepsia and abdominal pain have also occurred. As with some penicillins and some other cephalosporins, transient hepatitis and cholestatic jaundice have been reported rarely.

  Hypersensitivity: Allergic reactions have been observed in the form of rash, urticaria, angioedema, and, rarely, erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis. These reactions usually subsided upon discontinuation of the drug, although in some cases supportive therapy may be necessary. Anaphylaxis has also been reported.

  Haemic and lymphatic system: Eosinophilia, neutropenia, thrombocytopenia, and haemolytic anaemia have been reported.

  Other: These have included genital and anal pruritus, genital candidiasis, vaginitis and vaginal discharge, dizziness, fatigue, headache, agitation, confusion, hallucinations, arthralgia, arthritis, and joint disorder. Reversible interstitial nephritis has been reported rarely. Slight elevations in AST and ALT have been reported.