Cefalexin
Cephalosporin antibacterial
For more detailed drug information, see Cefalexin in the AMH.
Also known as cephalexin.
Dosage – Cefalexin
Dose and duration of therapy depends on the infection and its response to treatment.
Bacterial infections
1 month – 18 years, oral 12.5 mg/kg (maximum 500 mg) every 6 hours. Usual adult dose is 250 mg every 6 hours or 500 mg every 6–12 hours.
Serious bacterial infections (eg osteomyelitis)
1 month – 18 years, oral 25 mg/kg (maximum 1 g) every 6 hours.
Alternatively, 45 mg/kg (maximum 1.5 g) every 8 hours may be used.
Uncomplicated urinary tract infections
Empiric treatment
1–3 months, oral 45 mg/kg every 8 hours for 10 days.
3 months – 16 years, oral 20 mg/kg (maximum 750 mg) every 8 hours for 3 days.
>16 years, oral 500 mg every 12 hours for 5 days in women or for 7 days in men.
Prophylaxis
1 month –18 years, oral 12.5 mg/kg (maximum 250 mg) at night.
Minor skin infections (eg impetigo, paronychia)
1 month – 18 years, oral 25 mg/kg (maximum 1 g) every 12 hours.
Serious skin infections (eg cellulitis, boils)
1 month – 18 years, oral 12.5 mg/kg (maximum 500 mg) every 6 hours.
Alternatively, 20 mg/kg (maximum 750 mg) every 8 hours may be used.
Off-label use
Product information does not include doses for prophylaxis of UTI.
Practice points
dose and frequency may differ from the product information to improve adherence in children
consider dosage adjustment in severe renal impairment
prophylaxis of UTI in children is not always necessary; seek specialist advice
Products
Search for Cefalexin on the PBS
cap, 250 mg, 20, Cephalexin, Ibilex, Keflexa, PBS/PBS‑A[40]1,2
cap, 500 mg, 20, Cephalex, Cephalexin, Ibilex, Keflexa, PBS/PBS‑A[40]2,3
oral liquid, 25 mg/mL (powder), 100 mL, Ibilex, Keflexa, PBS
oral liquid, 50 mg/mL (powder), 100 mL, Ibilex, Keflexa, PBS
1 prophylaxis of UTI
2 infections requiring prolonged oral antibiotic; specific infections, see PBS
3 osteomyelitis
a generic brands available