What is the recommended dosage of cephalexin (a cephalosporin antibiotic) for a pediatric patient with cellulitis, weighing 41 pounds?

From the Guidelines

For a child weighing 41 pounds (approximately 18.6 kg) with cellulitis, the recommended dosage of cephalexin is 25-50 mg/kg/day divided into four equal doses, as stated in the guidelines by the Infectious Diseases Society of America 1. This translates to approximately 465-930 mg total daily dose, or about 116-232 mg per dose given four times daily. Some key points to consider when prescribing cephalexin for pediatric cellulitis include:

• A typical prescription would be cephalexin 125 mg four times daily or 250 mg twice daily for 7-10 days.
• The medication should be given at evenly spaced intervals throughout the day, and completing the full course is essential even if symptoms improve before finishing.
• Cephalexin can be taken with or without food, though taking it with food may help reduce stomach upset.
• Parents should monitor for signs of allergic reaction (rash, itching, swelling) and worsening infection (increasing redness, warmth, swelling, fever).
• Cephalexin works by inhibiting bacterial cell wall synthesis, making it effective against many skin pathogens including Staphylococcus and Streptococcus species that commonly cause cellulitis.
• If symptoms worsen or don't improve within 48-72 hours, medical reevaluation is necessary. It's also important to note that the guidelines provide recommendations for various disease entities, including impetigo, MSSA SSTI, and MRSA SSTI, and that cephalexin is just one of several antibiotic options available for treating these conditions 1.

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 Weight125 mg/5 mL250 mg/5 mL 20 kg (44 lb)1 to 2 tsp q.i.d.1/2 to 1 tsp q.i.d. 20 kg (44 lb)2 to 4 tsp b.i.d.1 to 2 tsp b.i.d.

For a pediatric patient weighing 41lbs, the closest weight listed is 44lb. The recommended dosage is 25 to 50 mg/kg in divided doses. For a patient weighing 41lbs (approximately 18.6kg), the dosage would be:

• 25 mg/kg: 18.6kg x 25mg/kg = 465mg per day
• 50 mg/kg: 18.6kg x 50mg/kg = 930mg per day

Using the provided suspension guidelines for a 44lb patient, the dosage can be administered as:

• 1 to 2 tsp q.i.d. (using 125 mg/5 mL) or
• 2 to 4 tsp b.i.d. (using 125 mg/5 mL)
• 1/2 to 1 tsp q.i.d. (using 250 mg/5 mL) or
• 1 to 2 tsp b.i.d. (using 250 mg/5 mL)

Given the patient's weight and the infection type (cellulitis), a dosage of 25 to 50 mg/kg in divided doses is recommended, but the exact dosage frequency (q.i.d. or b.i.d.) should be determined based on the specific infection severity and clinical judgment 2.

From the Research

Cephalexin Dosage for Pediatric Cellulitis

• The dosage of cephalexin for pediatric cellulitis is not explicitly stated in the provided studies, but we can look at the study that involved children with moderate cellulitis treated with high-dose oral cephalexin 3.
• In this study, the success rate of high-dose oral cephalexin was 89.7%, suggesting that it is effective and safe for the treatment of children with moderate cellulitis.
• However, the study does not provide a specific dosage for a child weighing 41lbs.
• Another study compared the effectiveness of different antibiotics, including cephalexin, for the treatment of cellulitis in adults and children, but it does not provide dosage information for pediatric patients 4.
• A study on empiric outpatient therapy with trimethoprim-sulfamethoxazole, cephalexin, or clindamycin for cellulitis found that cephalexin had a lower treatment success rate compared to trimethoprim-sulfamethoxazole, but it does not provide dosage information for pediatric patients 5.

Considerations for Treatment

• The choice of antibiotic and dosage should be based on the severity of the infection, the patient's weight, and other factors such as potential allergies or interactions with other medications.
• It is essential to consult with a healthcare professional to determine the appropriate dosage and treatment plan for a child with cellulitis.
• The studies suggest that high-dose oral cephalexin may be an effective treatment option for children with moderate cellulitis, but more research is needed to determine the optimal dosage and treatment duration 3, 4.