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Antibiotic (first-generation cephalosporin)

Cephalexin: uses, side effects & precautions

Also known as Keflex, Cefalexin, Ceporex.

Ces informations sont fournies à titre indicatif uniquement et ne constituent pas un avis médical. Consultez toujours un professionnel de santé qualifié pour toute préoccupation médicale personnelle. En cas d'urgence, appelez votre numéro d'urgence local.

What it is used for

  • Skin and soft-tissue infections
  • Some urinary tract infections
  • Ear, throat and respiratory infections
  • Certain bone infections
  • Some dental infections

How it works

Cephalexin is a cephalosporin antibiotic, related to penicillins. It stops bacteria from building their cell walls, causing them to break apart and die. It works against bacteria, not viruses.

How it is taken

Comes as capsules, tablets and a liquid (oral suspension). Take it exactly as your doctor or pharmacist directs and follow the label. It can be taken with or without food; taking it with food may reduce stomach upset. Complete the full course as advised.

No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.

Common side effects

  • Diarrhoea
  • Nausea
  • Stomach upset
  • Vomiting
  • Thrush
  • Headache

Serious effects — get help

  • Severe allergic reaction with swelling of the face or throat or breathing difficulty
  • Severe, persistent or bloody diarrhoea
  • Severe blistering or peeling skin reactions
  • Yellowing of the skin or eyes
  • Unusual bleeding or bruising

If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.

Interactions to watch

  • Blood thinners such as warfarin
  • Metformin
  • Probenecid
  • Some live vaccines
  • Other antibiotics

Who should take care

  • Tell your clinician about any penicillin or cephalosporin allergy
  • Tell your clinician if you have kidney problems
  • Discuss pregnancy or breastfeeding with your doctor or pharmacist
  • Mention all other medicines you take
  • Complete the course even if you feel better

Frequently asked questions

Can I take cephalexin if I am allergic to penicillin?
Cephalosporins are related to penicillins, so there is a small chance of cross-reaction. Always tell your clinician about any penicillin allergy before taking it.
Can it treat a cold?
No. Colds are caused by viruses, and cephalexin only works against bacteria.
Should I take it with food?
It can be taken with or without food. Taking it with food can help if it upsets your stomach.
Is it safe in pregnancy?
Cephalexin is often considered suitable, but you should still confirm with your doctor or pharmacist for your situation.

Related conditions

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