What is the recommended dose of Ceftriaxone (Zocyn) for treating pneumonia?

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Last updated: September 23, 2025View editorial policy

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Recommended Ceftriaxone Dosing for Pneumonia

For community-acquired pneumonia (CAP), the recommended dose of ceftriaxone is 1-2 g IV once daily, with 1 g daily being sufficient for most cases of moderate severity. 1

Dosing Guidelines Based on Severity and Setting

Outpatient/Non-severe CAP

  • Ceftriaxone 1 g IV/IM once daily 1, 2
  • Often combined with a macrolide (azithromycin 500 mg daily or clarithromycin 500 mg twice daily) 1

Hospitalized, Non-ICU Patients

  • Ceftriaxone 1-2 g IV once daily + macrolide 1
  • 1 g daily is generally sufficient for most cases 2, 3

Severe CAP/ICU Patients

  • Ceftriaxone 2 g IV once daily recommended 1, 4
  • Higher dose particularly beneficial in patients requiring mechanical ventilation (17.2% vs 20.4% mortality with 1 g dosing) 4

Special Considerations

Pathogen-Specific Dosing

  • S. pneumoniae: 1 g daily is typically sufficient 2, 3
  • MSSA infections: 2-4 g daily recommended (1 g daily associated with poor outcomes) 5
  • Drug-resistant S. pneumoniae: Consider 2 g IV once daily 1

Patient Factors Affecting Dosing

  • Renal function: No dosage adjustment needed for renal impairment
  • Severe infections: Higher end of dosing range (2 g daily) recommended 1
  • Pseudomonas risk: Ceftriaxone is not effective; alternative agents needed 1

Duration of Treatment

  • Continue until patient has been afebrile for 48-72 hours
  • Minimum 5 days for uncomplicated CAP
  • 7-14 days for complicated pneumonia 1

Important Caveats

  • Ceftriaxone alone is not effective against atypical pathogens (Mycoplasma, Chlamydia, Legionella) and should be combined with a macrolide or doxycycline 1
  • For patients with contraindications to macrolides, ceftriaxone + doxycycline 100 mg twice daily is an acceptable alternative 1
  • Meta-analysis shows 1 g daily dosing is as effective as 2 g daily for most CAP cases (OR 1.02,95% CI [0.91-1.14]) 2
  • Higher doses (2 g daily) may be associated with slightly increased risk of adverse events, particularly C. difficile infection (1.9% vs 1.8%) 4

Bottom Line

For most cases of community-acquired pneumonia, ceftriaxone 1 g IV once daily (combined with appropriate coverage for atypical pathogens) is effective. Reserve 2 g daily dosing for severe pneumonia requiring ICU admission/mechanical ventilation, suspected MSSA infection, or areas with high pneumococcal resistance.

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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