Cefalaxin for severe infections and guidance for treatment

Clinical answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 22 December 2025Updated: 22 December 2025 Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Appropriate use of cephalexin in managing severe infections:

Cephalexin is a first-generation cephalosporin antibiotic primarily used for mild to moderate infections caused by susceptible Gram-positive bacteria. It is not typically the first choice for severe infections requiring intravenous therapy, where other cephalosporins like cefotaxime or ceftriaxone are preferred.

In severe infections, especially those requiring hospital management such as diabetic foot infections or bacterial meningitis, cephalexin is generally not recommended as first-line therapy. Instead, intravenous antibiotics with broader coverage and better tissue penetration are used initially, such as flucloxacillin, co-amoxiclav, gentamicin, ceftriaxone, or cefotaxime, depending on the infection and microbiological guidance ,.

Cephalexin may be considered for oral step-down therapy in less severe infections or when the patient is stable and able to take oral medication, but this should be guided by microbiological results and clinical response .

For skin and soft tissue infections, flucloxacillin is preferred due to its narrow spectrum targeting Staphylococcus aureus and beta-haemolytic streptococci, with cephalexin being less commonly recommended .

In summary, cephalexin is appropriate for mild to moderate infections but is not the recommended treatment for severe infections, where intravenous antibiotics with broader coverage are indicated initially, followed by oral step-down therapy guided by clinical and microbiological response ,,.

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