What is the recommended dose of ceftriaxone (Ceftriaxone) for an adult patient with Lower Respiratory Tract Infection (LRTI)?

Adult Dose of Ceftriaxone in LRTI

For adult patients with lower respiratory tract infections, ceftriaxone should be administered at 1 gram intravenously or intramuscularly every 12 hours (or 2 grams once daily), with treatment duration of 7-14 days depending on clinical response. 1

Standard Dosing Regimen

• The recommended dose is ceftriaxone 1 gram IV or IM every 12 hours, which provides adequate coverage for strains with penicillin MICs ≤8 mg/L 1
• Alternatively, 2 grams once daily can be administered for community-acquired pneumonia, offering the convenience of single daily dosing 2
• The usual adult daily dose ranges from 1 to 2 grams given once daily or in equally divided doses twice daily, with a maximum of 4 grams per day 2

Treatment Duration and Monitoring

• Continue therapy for at least 2 days after signs and symptoms of infection have disappeared 2
• The usual duration is 4-14 days; complicated infections may require longer therapy 2
• Assess clinical response at day 2-3 by monitoring fever and progression of pulmonary infiltrates 1
• Treatment should generally not exceed 8 days in responding patients to minimize resistance selection 3

Administration Considerations

• Administer intravenously over 30 minutes in adults 2
• Do not use diluents containing calcium (such as Ringer's solution or Hartmann's solution) as precipitation can occur 2
• Ceftriaxone must not be administered simultaneously with calcium-containing IV solutions via Y-site 2

Pathogen Coverage and Clinical Context

• Ceftriaxone provides excellent coverage for Streptococcus pneumoniae (including penicillin-resistant strains with MICs ≤8 mg/L), Haemophilus influenzae, and Moraxella catarrhalis 1
• For atypical pathogen coverage (Legionella, Mycoplasma, Chlamydophila), ceftriaxone must be combined with a macrolide or fluoroquinolone 1
• Clinical cure rates of 93-95% have been demonstrated in hospitalized patients with LRTI 4, 5

Dosage Adjustments

• No dosage adjustment is necessary for renal or hepatic impairment in adults receiving up to 2 grams per day 2
• No modification needed in elderly patients provided there is no severe renal and hepatic impairment 2

Common Pitfalls to Avoid

• Do not use ceftriaxone as monotherapy for community-acquired pneumonia requiring hospitalization without adding atypical coverage, as this leaves Legionella and Mycoplasma uncovered 1
• Do not use oral cephalosporins for infections caused by strains with penicillin MICs >2 mg/L, as they are inadequate 1
• Avoid extending treatment beyond what is clinically necessary, as this increases resistance selection without added benefit 3