What is the recommended dose of Keflex (Cephalexin) for pediatric patients with streptococcal infections?

Cephalexin Dosing for Pediatric Streptococcal Infections

For pediatric patients with streptococcal infections, the recommended dose of cephalexin (Keflex) is 20 mg/kg per dose twice daily (maximum = 500 mg per dose) for 10 days. 1

Dosing Guidelines for Group A Streptococcal Infections

• For streptococcal pharyngitis in pediatric patients over 1 year of age, the total daily dose may be divided and administered every 12 hours (twice daily) 2
• The FDA-approved dosing for streptococcal infections in children is 25-50 mg/kg/day divided into doses 2
• For Group A Streptococcal infections, cephalexin is considered a strong recommendation with high-quality evidence in penicillin-allergic patients 1
• The full 10-day course of therapy is essential to prevent rheumatic fever and other complications 1

Weight-Based Dosing Chart

For streptococcal infections using 250 mg/5 mL suspension:

• 10 kg (22 lb): ½ to 1 tsp twice daily 2
• 20 kg (44 lb): 1 to 2 tsp twice daily 2
• 40 kg (88 lb): 2 to 4 tsp twice daily 2

Clinical Evidence Supporting Cephalexin Use

• Cephalexin has been shown to be more effective than penicillin in treating Group A beta-hemolytic streptococcal throat infections in children, with lower clinical failure rates (3% vs 8%) and bacteriologic failure rates (7% vs 11%) 3
• Twice-daily (BID) and four-times-daily (QID) administration of cephalexin have been demonstrated to be equally effective in treating Group A streptococcal pharyngitis, with failure rates of 7.3% and 5.3% respectively 4
• For optimal efficacy, the mean daily dose should be approximately 30 mg/kg regardless of frequency of administration 4

Alternative Antibiotic Options

• For patients without penicillin allergy, first-line options include:

  • Penicillin V (oral): 250 mg two or three times daily for children, for 10 days 1
  • Amoxicillin (oral): 50 mg/kg once daily (maximum = 1,000 mg) for 10 days 1

• For patients with immediate hypersensitivity to penicillin (who should avoid cephalexin):

  • Clindamycin (oral): 7 mg/kg per dose three times daily (maximum = 300 mg per dose) for 10 days 1
  • Azithromycin (oral): 12 mg/kg once daily (maximum = 500 mg) for 5 days 1

Important Clinical Considerations

• Cephalexin should be avoided in individuals with immediate hypersensitivity to penicillin 1
• Twice-daily dosing of cephalexin improves medication adherence while maintaining clinical efficacy 4, 5
• For severe infections, the dosage may need to be doubled 2
• Cephalexin is rapidly absorbed in the upper intestine and achieves effective tissue concentrations quickly 6
• Children may require higher doses per kilogram than adults due to their greater body water turnover 6

Treatment Duration

• For Group A streptococcal infections, a full 10-day course of cephalexin is required to prevent complications such as rheumatic fever 1, 2
• Early clinical improvement should not be a reason to discontinue therapy before completing the full course 1