what is cefalexin used for

Cefalexin (also spelled cephalexin) is an antibiotic used to treat a range of bacterial infections, especially of the urinary , skin, ear, respiratory tract, and bones. It only works for bacterial infections, not for colds, flu, or other viral illnesses.

What cefalexin is used for

Common infections where cefalexin is prescribed include:

• Urinary tract and bladder infections (UTIs).
• Skin and soft tissue infections (for example cellulitis, infected wounds, some boils).
• Ear infections such as otitis media.
• Respiratory infections, including some chest infections, bronchitis, and strep throat.
• Certain types of bone and joint infections.

In some cases, it is also used to help prevent infections, for example around surgery or in people at risk of heart valve infection having dental or throat procedures.

How it works (in simple terms)

• Cefalexin is a first‑generation cephalosporin antibiotic.
• It works by damaging the bacterial cell wall so the bacteria break apart and die, helping your body clear the infection.

Important limits and cautions

• It does not work for viral infections such as colds, flu, or COVID‑19, and using it when not needed can encourage antibiotic resistance.

• It may be used as an alternative in some people who cannot take penicillin, but there can be cross‑allergy, so doctors are cautious in those with serious penicillin allergy.

• It is not effective against some resistant bacteria such as MRSA and certain hospital‑type germs.

Typical side‑effect snapshot

Most people tolerate cefalexin well, but side effects can include:

• Nausea, vomiting, or diarrhoea.
• Abdominal discomfort or indigestion.
• Rash or itching; more rarely, serious allergic reactions.

If someone has trouble breathing, swelling of the face or throat, or a widespread rash after taking cefalexin, that is an emergency and needs urgent medical attention.

Quick safety reminders

• Always take it exactly as prescribed and finish the course, even if you feel better early, unless a doctor tells you to stop.

• Do not share leftover antibiotics with others or use them later for a new illness without medical advice.

• If you have kidney disease, are pregnant, breastfeeding, or have a history of severe antibiotic allergy, dosing and suitability need to be checked by a clinician.

This information is general and cannot replace advice from your own doctor or pharmacist. If cefalexin has been prescribed for you, follow the instructions on your label and ask a health professional if anything is unclear.