What is the recommended dose of Keflex (Cephalexin) for a 7-year-old child with a sinus infection?

Recommended Dose of Keflex (Cephalexin) for a 7-Year-Old Child with Sinus Infection

For a 7-year-old child with sinus infection, the recommended dose of Keflex (cephalexin) is 75-100 mg/kg/day divided into 2-4 doses, with a typical regimen being 25-50 mg/kg/day divided every 12 hours for 7-10 days.

Dosing Considerations

The appropriate dosing for cephalexin in pediatric sinus infections should be based on:

• Weight-based calculation: For a typical 7-year-old (approximately 20-25 kg)
• Severity of infection: Mild to moderate vs. severe
• Local resistance patterns: Consider higher doses in areas with resistant organisms

Standard Dosing Options:

• Mild to moderate infection: 25-50 mg/kg/day divided every 12 hours
• More severe infection: 75-100 mg/kg/day divided every 6-8 hours

Treatment Duration

Treatment should continue for:

• 7-10 days for uncomplicated sinusitis 1
• Continue treatment until the child has been symptom-free for at least 7 days 1

First-Line Treatment Considerations

While cephalexin can be used for sinus infections, it's important to note that current guidelines from the American Academy of Pediatrics actually recommend amoxicillin or amoxicillin-clavulanate as first-line therapy for pediatric sinusitis:

• First choice: Amoxicillin at 45 mg/kg/day in 2 divided doses for standard treatment 1
• For high-risk situations: Amoxicillin-clavulanate at 80-90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day of clavulanate in 2 divided doses 1

High-risk situations include:

• Children younger than 2 years
• Attendance at childcare
• Recent antimicrobial use (within past 30 days)
• Areas with high prevalence of resistant S. pneumoniae

When to Use Cephalexin

Cephalexin may be appropriate in the following scenarios:

• Non-type I penicillin allergy
• Known susceptibility of local pathogens to cephalexin
• Previous successful treatment with cephalexin

Monitoring and Follow-Up

• Assess clinical improvement within 48-72 hours
• Look for decreased nasal discharge, improved breathing, and resolution of fever
• If no improvement after 48-72 hours, consider changing antibiotics or reassessing diagnosis

Common Pitfalls to Avoid

1. Underdosing: Inadequate dosing may lead to treatment failure and promote resistance
2. Incorrect frequency: Twice-daily dosing is generally adequate for cephalexin in sinusitis
3. Premature discontinuation: Completing the full course is essential even if symptoms improve quickly
4. Not considering first-line alternatives: Amoxicillin or amoxicillin-clavulanate may be more appropriate first choices based on current guidelines

Remember that while cephalexin has shown efficacy in treating sinusitis 2, current pediatric infectious disease guidelines favor amoxicillin-based regimens as first-line therapy for pediatric sinusitis due to better coverage of common pathogens.