What is the appropriate dose of intramuscular (IM) ceftriaxone for a 13-year-old patient weighing 33.57 kilograms?

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Last updated: February 16, 2025View editorial policy

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From the Guidelines

For a 13-year-old patient weighing 33.57kg, the recommended dose of intramuscular ceftriaxone is 100mg/kg/day [ 1 ]. Based on this guideline, the maximum dose for this patient would be approximately 3.357g, as 100mg/kg would calculate to 3.357g. However, the recommended dose should not exceed 1g per dose for intramuscular administration [ 1 ]. Therefore, a dose of 1g of ceftriaxone administered intramuscularly is recommended for this patient, and this dose may be repeated every 24 hours as needed.

Important Considerations

  • The dose of ceftriaxone for pediatric patients should not exceed that of a normal adult [ 1 ].
  • Ceftriaxone can be administered intravenously or intramuscularly [ 1 ].
  • The recommended dose of ceftriaxone for pediatric patients is 100mg/kg/day [ 1 ].

Administration

  • Ceftriaxone should be administered intramuscularly in a dose not exceeding 1g [ 1 ].
  • For doses greater than 1g, ceftriaxone should be administered intravenously [ 1 ].
  • Patients should be informed that intramuscular injection of ceftriaxone is painful [ 1 ].

From the FDA Drug Label

For the treatment of skin and skin structure infections, the recommended total daily dose is 50 to 75 mg/kg given once a day (or in equally divided doses twice a day). For the treatment of acute bacterial otitis media, a single intramuscular dose of 50 mg/kg (not to exceed 1 gram) is recommended For the treatment of serious miscellaneous infections other than meningitis, the recommended total daily dose is 50 to 75 mg/kg, given in divided doses every 12 hours. In the treatment of meningitis, it is recommended that the initial therapeutic dose be 100 mg/kg (not to exceed 4 grams).

The appropriate dose of intramuscular (IM) ceftriaxone for a 13-year-old patient weighing 33.57 kilograms depends on the type and severity of infection.

  • For skin and skin structure infections, the dose is 50 to 75 mg/kg once a day, which would be 1687.5 to 2515.25 mg (but not to exceed 2 grams).
  • For acute bacterial otitis media, the dose is a single intramuscular dose of 50 mg/kg, which would be 1678.5 mg (but not to exceed 1 gram).
  • For serious miscellaneous infections, the dose is 50 to 75 mg/kg every 12 hours, which would be 1678.5 to 2517.75 mg per day (but not to exceed 2 grams).
  • For meningitis, the dose is 100 mg/kg (but not to exceed 4 grams), which would be 3357 mg (but this exceeds the recommended dose, so the dose would be 4 grams or less, depending on the specific circumstances) 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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