Cefaclor

How it works

It is bactericidal, binding penicillin-binding proteins to inhibit bacterial cell-wall synthesis and cause cell lysis.

Prescribing in practice

• Avoid in patients with a history of immediate hypersensitivity to penicillins or cephalosporins, as cross-reactivity can cause serious allergic reactions.
• A serum-sickness-like reaction with rash and arthralgia is recognised, particularly in children, and should prompt discontinuation.
• As with other broad-spectrum antibiotics, it can precipitate Clostridioides difficile infection.

Monitoring

Routine laboratory monitoring is not required; review clinical response and watch for hypersensitivity or new diarrhoea.

Counselling the patient

• Complete the full prescribed course even once you feel better.
• Stop and seek urgent advice if you develop a rash, joint pains, swelling or breathing difficulty.
• Report severe or persistent diarrhoea rather than treating it yourself.

Evidence & guidelines

Cefaclor is a long-established oral cephalosporin with efficacy supported by extensive clinical use and the SPC.