What is the appropriate dose of Rocephin (Ceftriaxone) for a 13-year-old male weighing 73.6 pounds?

Ceftriaxone Dosing for a 13-Year-Old Male Weighing 73.6 Pounds

For a 13-year-old male weighing 73.6 pounds (33.4 kg), the appropriate dose of Rocephin (ceftriaxone) is 50-75 mg/kg/day for most infections, which translates to 1,670-2,505 mg daily, typically given as 1-2 grams once daily or divided every 12 hours depending on infection severity. 1, 2

Weight-Based Dosing Calculation

• Patient weight: 73.6 pounds = 33.4 kg
• Standard pediatric dosing: 50-75 mg/kg/day for most infections 1, 2
• Calculated dose range: 1,670 mg (50 mg/kg × 33.4 kg) to 2,505 mg (75 mg/kg × 33.4 kg) daily
• Practical dosing: Round to 1-2 grams daily based on infection severity 2

Infection-Specific Dosing Recommendations

For Less Severe Infections (Skin/Soft Tissue, Uncomplicated Pneumonia)

• Dose: 50-75 mg/kg/day, given as 1-2 grams once daily 1, 2
• Maximum: Do not exceed 2 grams daily for routine infections 2

For Severe Infections (Bacteremia, Complicated Pneumonia)

• Dose: 50-100 mg/kg/day, given as 1-2 grams once daily or divided every 12 hours 1, 2
• Maximum: Do not exceed 2 grams daily unless treating meningitis 2

For Meningitis

• Initial dose: 100 mg/kg (not to exceed 4 grams) 2
• Maintenance: 100 mg/kg/day divided every 12 hours or once daily 1
• For this patient: 3.3 grams daily (100 mg/kg × 33.4 kg), but practical dosing would be 2 grams every 12 hours (4 grams total daily) 1, 2

Administration Considerations

• Route: Can be given intramuscularly or intravenously 2
• IM preparation: Reconstitute with appropriate diluent; inject into large muscle mass 2
• IV administration: Infuse over 30 minutes for pediatric patients (60 minutes only required for neonates) 2
• Frequency: Once-daily dosing is appropriate for most infections due to ceftriaxone's long half-life 3, 4

Critical Caveats

• This patient weighs >40 kg (88 lb): Some guidelines suggest using adult dosing regimens for children ≥45 kg, but at 73.6 pounds (33.4 kg), this patient remains below that threshold and should use pediatric weight-based dosing 5, 6
• Maximum daily dose: The total daily dose should not exceed 4 grams, which only applies to meningitis cases 2
• Duration: Continue therapy for at least 2 days after signs and symptoms resolve; typical duration is 4-14 days depending on infection type 2
• Streptococcal infections: Continue for at least 10 days when treating Streptococcus pyogenes 2

Common Pitfalls to Avoid

• Do not underdose severe infections: Use the higher end of the dosing range (75-100 mg/kg/day) for serious infections like bacteremia or complicated pneumonia 1
• Do not exceed 2 grams daily for non-meningitis infections: The FDA label clearly states this maximum for routine pediatric infections 2
• Do not use calcium-containing diluents: Avoid Ringer's solution or Hartmann's solution due to risk of precipitation 2
• Do not assume adult dosing applies: At 73.6 pounds, this patient is below the 88-pound threshold where some sources suggest adult dosing 5