Cephalexin Dosage and Efficacy for Skin Infections

Adult Dosing

The standard adult dosage for skin infections is 500 mg orally four times daily (qid) for 7-10 days, depending on clinical response 1, 2, 3
The American College of Physicians recommends a duration of therapy of 7-10 days, depending on clinical response 1, 3

For children weighing less than 40 kg, the recommended dosage is 25-50 mg/kg/day in 4 divided doses 1
The duration of therapy for pediatric patients is 7-10 days, depending on clinical response 1

Cephalexin is effective against common skin pathogens, including methicillin-susceptible Staphylococcus aureus (MSSA) and Streptococcus species 1, 2
For patients with penicillin allergy (except those with immediate hypersensitivity reactions), cephalexin is a suitable alternative 1
Cephalexin is ineffective against methicillin-resistant Staphylococcus aureus (MRSA) 2
For suspected MRSA infections, consider alternative agents such as trimethoprim-sulfamethoxazole, clindamycin, or linezolid 3, 1

For pregnant patients, Cephalexin is FDA pregnancy category B and generally considered safe 4

Clinical response should be evident within 48-72 hours of initiating therapy 1
If no improvement is seen within 72 hours, consider alternative diagnoses or resistant organisms 3
Complete the full course of antibiotics even if symptoms improve before completion 1