Cephalexin Dosing Recommendations
For pediatric patients, the recommended dose of cephalexin is 25-50 mg/kg/day divided into 3-4 doses. 1
Pediatric Dosing Guidelines
Standard Dosing
- For most infections in children, cephalexin should be dosed at 25-50 mg/kg/day divided into 3-4 doses 1, 2
- For methicillin-susceptible Staphylococcus aureus (MSSA) infections, the preferred oral dosing is 75-100 mg/kg/day in 3 or 4 divided doses 2
- For skin and skin structure infections, the total daily dose may be divided and administered every 12 hours 1
Dosing by Infection Type
- For impetigo: 25-50 mg/kg/day in 3-4 divided doses 2
- For MSSA skin and soft tissue infections: 75-100 mg/kg/day in 3-4 divided doses 2
- For severe infections, the dosage may be doubled 1
- For otitis media, clinical studies have shown that a higher dosage of 75-100 mg/kg/day in 4 divided doses is required 1
Alternative Dosing Schedules
- Three-times-daily dosing: Recent evidence supports using 45 mg/kg/dose (maximum 1.5 g) three times daily for bone and joint infections with good efficacy and tolerability 3
- Twice-daily dosing: For MSSA infections with MICs of 1-2 mg/L, doses of 22-45 mg/kg twice daily may be effective 4
Administration Considerations
- Cephalexin can be administered with or without food 1
- For streptococcal infections, therapy should be continued for at least 10 days to prevent rheumatic fever 1
- For cystitis in patients over 15 years old, therapy should be continued for 7-14 days 1
Special Populations
- For patients with renal impairment (creatinine clearance <30 mL/min), dose reduction is necessary proportional to the reduced renal function 5
- Children may need higher doses per kilogram than adults due to their greater body water turnover 5
Practical Dosing Chart
For cephalexin suspension:
- 10 kg (22 lb) child: 1/2 to 1 tsp (125 mg/5 mL) four times daily or 1 to 2 tsp twice daily 1
- 20 kg (44 lb) child: 1 to 2 tsp (125 mg/5 mL) four times daily or 2 to 4 tsp twice daily 1
- 40 kg (88 lb) child: 2 to 4 tsp (125 mg/5 mL) four times daily or 4 to 8 tsp twice daily 1
Common Pitfalls and Caveats
- Underdosing is a common pitfall that can lead to treatment failure and potential resistance development 5
- While less frequent dosing regimens (twice or three times daily) may improve adherence, they require higher individual doses to maintain efficacy 4
- For severe infections, parenteral therapy may be more appropriate initially before transitioning to oral cephalexin 2
- Always consider local resistance patterns when selecting cephalexin for empiric therapy 2