What is the correct dose of cephalexin (cephalexin) for a 47-pound child with periorbital (around the eye) or periungual (around the nail) cellulitis, specifically periungual cellulitis?

From the Guidelines

For a 47-pound child with periungual cellulitis, the recommended dose of cephalexin is 75-100 mg/kg/day PO divided q6-8 h, which translates to approximately 1076.25-1425 mg per day, divided into 3-4 doses, with a maximum dose of 4000 mg/day. This dosing regimen is based on the most recent and highest quality evidence available, as outlined in the study published in the Journal of Microbiology, Immunology and Infection in 2019 1. Given the child's weight of 47 pounds (21.3 kg), the calculated dose would be:

• 75 mg/kg/day: 21.3 kg * 75 mg/kg = 1597.5 mg per day, divided into 3-4 doses
• 100 mg/kg/day: 21.3 kg * 100 mg/kg = 2130 mg per day, divided into 3-4 doses A typical regimen would be 375-530 mg of cephalexin every 6-8 hours for 7-10 days. It is essential to complete the entire course of antibiotics even if symptoms improve before finishing, and to ensure adequate fluid intake while on this medication. Cephalexin should be given with or without food, though taking it with food may help reduce stomach upset. Monitor for improvement within 48-72 hours; if the infection worsens or doesn't improve, medical reassessment is necessary. The chosen dosing maintains consistent blood levels of the antibiotic to effectively fight the infection, considering cephalexin's good coverage against common causative organisms like Staphylococcus aureus and Streptococcus species.

From the FDA Drug Label

Pediatric Patients The usual recommended daily dosage for pediatric patients is 25 to 50 mg/kg in divided doses For streptococcal pharyngitis in patients over 1 year of age and for skin and skin structure infections, the total daily dose may be divided and administered every 12 hours. Cephalexin Suspension Weight 125 mg/5 mL 250 mg/5 mL 20 kg (44 lb) 1 to 2 tsp q.i.d. 1/2 to 1 tsp q.i.d.

In severe infections, the dosage may be doubled.

For a 47-pound child, the weight is closest to 20 kg (44 lb). The recommended daily dosage for pediatric patients is 25 to 50 mg/kg. For a 47-pound (21.3 kg) child, the dose would be 25 to 50 mg/kg, which is approximately 532.5 to 1065 mg per day. Since the child has periungual cellulitis, which is a skin and skin structure infection, the total daily dose may be divided and administered every 12 hours. The dose for a 20 kg (44 lb) child is 1 to 2 tsp q.i.d. for 125 mg/5 mL or 1/2 to 1 tsp q.i.d. for 250 mg/5 mL. However, since the exact weight is not listed, and the child's weight is 47 pounds, which is slightly more than 20 kg (44 lb) but less than 40 kg (88 lb), the dose should be adjusted accordingly. Considering the child's weight and the recommended dosage, the dose could be approximately 1 1/4 to 2 1/2 tsp of 125 mg/5 mL or 3/4 to 1 1/4 tsp of 250 mg/5 mL, given every 12 hours for skin and skin structure infections, but this is an estimate and the actual dose may vary. In severe infections, the dosage may be doubled. Given the information provided and the need for a conservative clinical decision, it is recommended to consult the FDA label and a medical professional for the exact dosage for this specific case 2.

From the Research

Dosing of Cephalexin for Periungual Cellulitis in Children

• The correct dose of cephalexin for a 47-pound child with periungual cellulitis is not explicitly stated in the provided studies 3, 4, 5, 6, 7.
• However, a study on outpatient management of moderate cellulitis in children using high-dose oral cephalexin 7 may provide some guidance on dosing.
• The study 7 used a high-dose oral cephalexin treatment guideline, but the exact dose is not specified in the provided text.
• Another study 4 mentions that cephalexin was the oral antibiotic most often prescribed for noncomplicated, nonfacial cellulitis, but the dose is not provided.

Considerations for Antibiotic Selection and Dosing

• Antibiotic selection is determined by patient history and risk factors, severity of clinical presentation, and the most likely microbial culprit 3.
• The choice of antibiotic and dosing should optimize pharmacodynamic target attainment 5.
• Antimicrobial stewardship programs can help create pathways for optimal antibiotic selection and dosing 5.