This site is intended for UK healthcare professionals
Medscape UK Univadis Logo
Medscape UK Univadis Logo

Cefalexin oral

Updated 2 Feb 2023 | Cephalosporins


Oral formulations of cefalexin (as cefalexin monohydrate)

Drugs List

  • cefalexin 125mg/5ml oral suspension
  • cefalexin 125mg/5ml oral suspension sugar-free
  • cefalexin 250mg capsules
  • cefalexin 250mg tablets
  • cefalexin 250mg/5ml oral suspension
  • cefalexin 250mg/5ml oral suspension sugar-free
  • cefalexin 500mg capsules
  • cefalexin 500mg tablets
  • Therapeutic Indications


    Antibiotic sensitive infections

    Treatment of the following infections due to susceptible Gram-positive and Gram-negative micro-organisms:
    Respiratory tract infections, otitis media, skin and soft tissue infections, bone and joint infections and genito-urinary tract infections (including acute prostatitis and dental infections)

    Unlicensed Uses

    Prophylaxis of recurrent urinary tract infections

    Prophylaxis against recurrent urinary tract infections.



    1g to 4g daily in divided doses.
    Most infections will respond to 250mg every 6 hours, or 500mg every 8 to 12 hours.
    In severe infections, increase dose to 1g to 1.5g every 6 to 8 hours.
    When daily doses of greater than 4g are required, the use of a parenteral cephalosporin should be considered.

    Prophylaxis of recurrent urinary tract infection (unlicensed)
    125mg every night.


    25mg/kg to 50mg/kg in divided doses. For severe infections, the dosage may be doubled.
    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 aged 5 years and over: 250mg every 8 hours.
    Children aged under 5 years: 125mg every 8 hours.

    Otitis media
    75mg/kg to 100mg/kg daily in four divided doses.

    The following alternative dosage schedule may be suitable:

    Infections due to sensitive Gram-positive and Gram negative bacteria
    Children aged 12 to 18 years: 500mg two to three times daily, increased to 1g to 1.5g three to four times daily for severe infection.
    Children aged 5 to 12 years: 250mg three times daily.
    Children aged 1 to 5 years: 125mg three times daily.
    Children aged 1 month to 1 year: 125mg twice daily.

    Prophylaxis of recurrent urinary tract infection (unlicensed)
    Children aged 1 month to 18 years: 12.5mg/kg at night (maximum 125mg at night).


    Neonate aged 21 to 28 days: 25mg/kg (maximum 125mg) four times daily.
    Neonate aged 7 to 21 days: 25mg/kg (maximum125mg) three times daily.
    Neonate aged under 7 days: 25mg/kg (maximum 125mg) twice daily.

    Patients with Renal Impairment

    If renal impairment is severely impaired (glomerular filtration rate less than 10ml/minute) dosage should be reduced to a daily maximum dosage of 500mg.

    The Renal Drug Handbook suggests the following dosage adjustment in renal impairment:
    Glomerular filtration rate (ml/minute)
    GFR 10 to 20ml/minute: 250mg to 500mg every 8 to 12 hours.
    GFR below 10ml/minute: 250mg to 500mg every 8 to 12 hours.

    Additional Dosage Information

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


    None known

    Precautions and Warnings

    Glucose-galactose malabsorption syndrome
    Hereditary fructose intolerance
    Lactose intolerance
    Severe renal impairment

    Reduce dose in patients with severe renal impairment
    Before initiating therapy enquire about previous hypersensitivity reactions
    Presentations with sorbitol unsuitable in hereditary fructose intolerance
    Some formulations contain lactose
    Some formulations contain sucrose
    Monitor periodically for overgrowth of non-susceptible organisms
    Consider pseudomembranous colitis if patient presents with diarrhoea
    Prolonged use may result in superinfection with non-susceptible organisms
    May cause false positive Coomb's test and glycosuria test
    Discontinue at once if pseudomembranous colitis occurs
    Discontinue if drug-related rash or other hypersensitivity reactions occur
    Advise patient to avoid zinc products 3 hours before or after dose

    Before therapy is initiated, it should be determined whether the patient has shown previous hypersensitivity to cephalosporins, penicillins, or other drugs. Cefalexin should be given cautiously to patients who have shown hypersensitivity to penicillins, as there is some evidence of partial cross-allergenicity between the penicillins and cephalosporins.

    There is a possibility of development of pseudomembranous colitis and it is therefore important to consider its diagnosis in patients who develop diarrhoea whilst taking cefalexin. The condition may range in severity from mild to life threatening with mild cases usually responding to cessation of therapy. Appropriate measures should be taken in moderate to severe cases.

    Pregnancy and Lactation


    Use cefalexin with caution in pregnancy.

    Although laboratory and clinical studies have shown no evidence of teratogenicity, caution should be exercised when prescribing for pregnant women.

    Cephalosporins can cross the placenta and can reach therapeutic levels in amniotic fluid and foetal tissues. Also the elimination of cephalosporins in pregnancy is faster and therefore may be necessary to adjust the dosage.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Use cefalexin with caution in breastfeeding.

    Cefalexin can pass into breast milk after oral dosing. The amount available to the nursing infant is between 0.5 and 1% of the maternal weight adjusted dose which is significantly lower than the recommended infant dosing regimen.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Abdominal pain
    Alterations in hepatic enzymes
    Anal pruritus
    Antibiotic-associated colitis
    Aplastic anaemia
    Cholestatic jaundice
    Erythema multiforme
    Genital candidiasis
    Genital pruritus
    Haemolytic anaemia
    Hypersensitivity reactions
    Increase in serum ALT/AST
    Interstitial nephritis (reversible)
    Joint disorder
    Overgrowth by non-susceptible organisms
    Pseudomembranous colitis
    Serum sickness-like reactions
    Sleep disturbances
    Stevens-Johnson syndrome
    Toxic epidermal necrolysis
    Vaginal discharge

    Effects on Laboratory Tests

    Positive direct Coombs' tests have been reported during treatment with 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 sulfate test tablets. Tests based on glucose oxidation reactions may be safely used.


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: January 2015

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Summary of Product Characteristics: Cefalexin 125mg/5mg Oral Suspension. Aurobindo Pharma - Milpharm Ltd. Revised September 2012.
    Summary of Product Characteristics: Cefalexin 250mg/5ml Oral Suspension. Aurobindo Pharma - Milpharm Ltd. Revised March 2012.
    Summary of Product Characteristics: Cefalexin 250mg Capsules. Aurobindo Pharma - Milpharm Ltd. Revised January 2012.
    Summary of Product Characteristics: Cefalexin 500mg Capsules. Aurobindo Pharma - Milpharm Ltd. Revised January 2012.

    Summary of Product Characteristics: Cefalexin 250mg Capsules. Kent Pharma Ltd. Revised July 2013.
    Summary of Product Characteristics: Cefalexin 500mg Capsules. Kent Pharma Ltd. Revised July 2013.

    Summary of Product Characteristics: Cefalexin Oral Suspension BP 125mg/5mg. Sandoz Ltd. Revised July 2014.
    Summary of Product Characteristics: Cefalexin Oral Suspension BP 250mg/5ml. Sandoz Ltd. Revised July 2014.
    Summary of Product Characteristics: Cefalexin 250mg Tablets. Sandoz Ltd. Revised July 2014.
    Summary of Product Characteristics: Cefalexin 500mg Tablets. Sandoz Ltd. Revised July 2014.
    Summary of Product Characteristics: Cefalexin 500mg Capsules. Sandoz Ltd. Revised July 2014.

    Summary of Product Characteristics: Keflex tablets, Capsules and Granules. Flynn Pharma Ltd. Revised March 2011.

    The Renal Drug Handbook. 3rd edition. (2009) ed. Ashley, C and Currie, Radcliffe Publishing Ltd, Abingdon.

    NICE - Evidence Services
    Available at:
    Last accessed: 22 June 2017

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Cefalexin Last revised: 7 September, 2013
    Last accessed: 10 January, 2015

    Access the full UK drug database with a FREE Medscape UK Account
    It takes just a few minutes, and you’ll get unlimited access to information on over 11,000 UK drugs.
    Register for Free

    Already a member? Log in

    Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content

    FDB Logo

    FDB Disclaimer : FDB Multilex is intended for the use of healthcare professionals and is provided on the basis that the healthcare professionals will retain FULL and SOLE responsibility for deciding what treatment to prescribe or dispense for any particular patient or circumstance.