What is the recommended dose of ceftriaxone (Ceftriaxone) for adults?

Ceftriaxone Dosing for Adults

For most serious bacterial infections in adults, ceftriaxone should be dosed at 2 grams IV every 12 hours (total 4 grams daily), particularly for central nervous system infections including meningitis, where twice-daily dosing ensures adequate CSF concentrations throughout the treatment period. 1

Standard Adult Dosing by Infection Type

Central Nervous System Infections

• Bacterial meningitis (empiric): 2 grams IV every 12 hours for 10-14 days 1, 2
• Pneumococcal meningitis: 2 grams IV every 12 hours for 10-14 days (extend if slow to respond) 1
• Meningococcal meningitis: 2 grams IV every 12 hours for 5 days 1
• H. influenzae meningitis: 2 grams IV every 12 hours for 10 days 1
• Enterobacteriaceae CNS infections: 2 grams IV every 12 hours for 21 days 1

Gonococcal Infections

• Uncomplicated infections (cervical/urethral/rectal): 250 mg IM single dose 2, 3
• Disseminated gonococcal infection: 1 gram IM or IV every 24 hours, continue 24-48 hours after improvement, then switch to oral therapy to complete 7 days 2
• Gonococcal meningitis: 1-2 grams IV every 12 hours for 10-14 days 2
• Gonococcal endocarditis: 1-2 grams IV every 12 hours for at least 4 weeks 2
• Gonococcal conjunctivitis: 1 gram IM single dose 2

Endocarditis

• HACEK organisms: 2 grams IV/IM once daily for 4 weeks (6 weeks for prosthetic valve) 2
• Highly penicillin-susceptible viridans streptococci (MIC ≤0.12 μg/mL): 2 grams IV/IM once daily for 4 weeks as monotherapy 2

Other Serious Infections

• Skin and soft tissue infections: 1-2 grams once daily or divided twice daily depending on severity 3, 4
• Septicemia: 1-2 grams once daily or divided twice daily 3, 5
• General serious infections: 1-2 grams once daily or divided twice daily (maximum 4 grams daily) 3

Critical Dosing Considerations

When to Use Twice-Daily Dosing (2g Q12H)

• All CNS infections require twice-daily dosing initially to achieve rapid CSF sterilization and maintain therapeutic concentrations 1, 2
• Severe infections with high bacterial burden benefit from twice-daily dosing in the first 24-48 hours 6
• Infections with resistant organisms or elevated MICs may require sustained higher concentrations 2

When Once-Daily Dosing is Appropriate

• After clinical improvement in meningitis: May transition to once-daily dosing after initial 24-48 hours if patient is stable 7
• Uncomplicated gonococcal infections: Single dose or once-daily dosing is sufficient 2, 3
• Endocarditis with highly susceptible organisms: Once-daily dosing is effective 2
• Outpatient parenteral therapy: Once-daily dosing facilitates home administration 2, 6

Special Populations and Adjustments

Elderly Patients (≥60 Years)

• Add amoxicillin 2 grams IV every 4 hours to ceftriaxone 2 grams every 12 hours for suspected meningitis to cover Listeria monocytogenes 1, 2
• No dose reduction needed for age alone if renal/hepatic function is preserved 3

Resistant Organisms

• Penicillin-resistant pneumococci: Add vancomycin 15-20 mg/kg IV twice daily (target trough 15-20 mg/L) OR rifampicin 600 mg twice daily to ceftriaxone 2 grams every 12 hours 1, 2
• Pharyngeal gonorrhea with elevated MICs: Consider 2 grams twice daily to achieve adequate free plasma concentrations 2

Renal/Hepatic Impairment

• No dosage adjustment necessary for renal or hepatic impairment alone 3
• Maximum daily dose remains 4 grams even with organ dysfunction 3

Administration Guidelines

Intravenous Administration

• Infuse over 30 minutes for standard adult dosing 3
• Concentrations between 10-40 mg/mL are recommended 3
• Never mix with calcium-containing solutions (Ringer's, Hartmann's, parenteral nutrition) due to precipitation risk 3
• May administer sequentially with calcium-containing solutions if lines are thoroughly flushed between infusions 3

Intramuscular Administration

• Inject deep into large muscle mass with aspiration to avoid vascular injection 3
• IM injection is painful; warn patients accordingly 2
• Reconstitute to 250 mg/mL or 350 mg/mL concentration 3

Common Pitfalls to Avoid

Underdosing CNS Infections

• Never use once-daily dosing initially for meningitis - twice-daily dosing (2g Q12H) is essential for the first 24-48 hours to achieve rapid CSF sterilization 1, 2
• Recent evidence suggests once-daily dosing (2g Q24H) may be acceptable for penicillin-susceptible S. pneumoniae meningitis after initial stabilization, but this remains controversial 7

Missing Listeria Coverage

• Always add ampicillin/amoxicillin for patients ≥60 years with suspected meningitis, as ceftriaxone has no activity against Listeria 1, 2

Inadequate Treatment of Chlamydia

• Add antichlamydial coverage (azithromycin or doxycycline) when treating gonococcal infections if Chlamydia is not ruled out 2, 3

Calcium Precipitation

• Absolutely contraindicated in neonates ≤28 days receiving or expected to receive calcium-containing IV solutions 3
• In adults, never administer simultaneously with calcium-containing solutions via Y-site 3

Duration of Therapy

• Meningococcal meningitis: 5 days if clinically recovered 1, 2
• Pneumococcal meningitis: 10-14 days (longer if slow response) 1, 2
• H. influenzae meningitis: 10 days 1
• Enterobacteriaceae CNS infections: 21 days 1
• Endocarditis: 4 weeks (6 weeks for prosthetic valve) 2
• Disseminated gonococcal infection: 7 days total 2