Ceftriaxone Dosing for Adult Patients
The standard adult dose of ceftriaxone is 1-2 grams intravenously or intramuscularly once daily (or divided twice daily), with a maximum daily dose of 4 grams, depending on the type and severity of infection. 1, 2
Standard Dosing Guidelines
- The usual adult daily dose is 1 to 2 grams given once a day (or in equally divided doses twice a day) depending on the type and severity of infection 1
- The total daily dose should not exceed 4 grams 1
- Ceftriaxone can be administered intravenously (over 30 minutes) or intramuscularly 1
- No dosage adjustment is necessary for patients with impairment of renal or hepatic function, up to 2 grams per day 1, 3
- The dosages recommended for adults require no modification in elderly patients, up to 2 grams per day, provided there is no severe renal and hepatic impairment 1
Infection-Specific Dosing
Meningitis
- For bacterial meningitis: 2 grams IV every 12 hours (total 4 grams daily) 2, 4
- For pneumococcal meningitis: 2 grams IV every 12 hours for 10-14 days 4
- For meningococcal meningitis: 2 grams IV every 12 hours for 5 days 4
Other Serious Infections
- For disseminated gonococcal infection: 1 gram IM or IV every 24 hours, continued for 24-48 hours after improvement begins 2
- For gonococcal endocarditis: 1-2 grams IV every 12 hours for at least 4 weeks 2
- For Enterobacteriaceae infections in CSF/blood: 2 grams IV every 12 hours with treatment continued for 21 days 4
- For Haemophilus influenzae infections: 2 grams IV every 12 hours for 10 days 4
Less Severe Infections
- For uncomplicated gonococcal infections: a single intramuscular dose of 250 mg 1
- For preoperative use (surgical prophylaxis): a single dose of 1 gram administered intravenously 1/2 to 2 hours before surgery 1
- For skin and soft tissue infections: 1-2 grams once daily 5
Special Considerations
- For penicillin-resistant pneumococcal infections, adding vancomycin 15-20 mg/kg IV twice daily or rifampicin 600 mg twice daily to the ceftriaxone regimen is recommended 4
- For patients ≥60 years with suspected meningitis, adding amoxicillin 2 grams IV every 4 hours to cover Listeria monocytogenes is recommended 4
- For outpatient antibiotic therapy, ceftriaxone 2 grams twice daily IV initially, with option to use 4 grams once daily IV after the first 24 hours for patients who are clinically improving 2
- For infections caused by bacteria with elevated minimum inhibitory concentrations (MICs), higher doses or more frequent administration may be required 2
Pharmacokinetic Considerations
- Ceftriaxone has a long serum half-life (7.6-8.3 hours in healthy adults), which allows for once-daily dosing in most cases 6
- In patients with renal impairment, the elimination half-life is prolonged (11.7-17.3 hours), but dosage adjustment is generally not necessary when the daily dose is 2 grams or less 3, 7
- Plasma concentrations exceed the minimal inhibitory concentrations (MICs) of most susceptible organisms for 24 hours after a 1-gram dose 6
Administration Guidelines
- Intravenous administration should be over a period of 30 minutes 1
- For intramuscular administration, inject well within the body of a relatively large muscle 1
- Do not use diluents containing calcium, such as Ringer's solution or Hartmann's solution, to reconstitute ceftriaxone 1
Remember that treatment duration should be based on the type of infection and clinical response, typically ranging from 4-14 days, with longer therapy required for complicated infections 1.