Oral Cephalosporins Used in Pediatrics with Doses
Cephalexin (Keflex) is the primary oral cephalosporin used in pediatrics at a dose of 25-50 mg/kg/day divided into 3-4 doses, with higher doses of 75-100 mg/kg/day required for otitis media. 1, 2
Common Oral Cephalosporins and Dosing
Cephalexin (First-Generation)
- Standard dosing: 25-50 mg/kg/day divided into 3-4 doses 1, 2
- Otitis media: 75-100 mg/kg/day in 4 divided doses 1
- Streptococcal pharyngitis: Can be given as twice daily dosing 1
- Bone and joint infections: Higher doses of 45 mg/kg/dose (maximum 1.5 g) three times daily have shown efficacy 3
Alternative Dosing Schedules
- Twice daily (BID) dosing: 22-45 mg/kg/dose for MSSA with MIC of 1-2 mg/L 4
- Three times daily (TID) dosing: 15-25 mg/kg/dose for MSSA with MIC of 1-2 mg/L 4
Indications for Cephalexin in Pediatrics
- Skin and soft tissue infections (SSTI)
- Streptococcal pharyngitis
- Otitis media (except for H. influenzae infections, which have a 50% failure rate) 5
- Bone and joint infections (as oral continuation therapy) 3
- Methicillin-susceptible Staphylococcus aureus (MSSA) infections 4
Clinical Pearls
- For streptococcal pharyngitis, cephalexin has shown superior efficacy compared to penicillin with lower clinical failure rates (3% vs 8%) and bacteriological failure rates (7% vs 11%) 6
- Beta-hemolytic streptococcal infections should be treated for at least 10 days 1
- Cephalexin has excellent absorption from the upper intestine but is not absorbed from the stomach 7
- Children may require higher doses per kilogram than adults due to greater body water turnover 7
Formulations
- Available as oral suspension in two strengths:
- 125 mg/5 mL
- 250 mg/5 mL
Practical Weight-Based Dosing Guide
For 125 mg/5 mL suspension:
- 10 kg child: 1/2 to 1 tsp four times daily or 1-2 tsp twice daily
- 20 kg child: 1 to 2 tsp four times daily or 2-4 tsp twice daily
- 40 kg child: 2 to 4 tsp four times daily or 4-8 tsp twice daily
For 250 mg/5 mL suspension:
- 10 kg child: 1/4 to 1/2 tsp four times daily or 1/2-1 tsp twice daily
- 20 kg child: 1/2 to 1 tsp four times daily or 1-2 tsp twice daily
- 40 kg child: 1 to 2 tsp four times daily or 2-4 tsp twice daily 1
Adverse Effects
- Generally well-tolerated with relatively infrequent adverse effects
- Most common: gastrointestinal upset, rash, and urticaria 5
- Neutropenia can occur but is typically mild with no associated complications 3
Important Considerations
- For severe infections, parenteral cephalosporins should be considered if daily doses greater than 4g are required 1
- Dose adjustment is needed in patients with renal impairment (creatinine clearance <30 mL/min) 7
- After reconstitution, oral suspension should be stored in the refrigerator and may be kept for 14 days without significant loss of potency 1