What are the doses of drugs used in mg/kg for meningitis treatment?

Dosing of Drugs for Bacterial Meningitis Treatment

The standard dosing for bacterial meningitis treatment in adults is ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours, with additional agents based on age and suspected pathogens. 1

Adult Dosing

First-line Treatment

• Adults <60 years:

  • Ceftriaxone: 2g IV every 12 hours 2
  • OR Cefotaxime: 2g IV every 6 hours 2

• Adults ≥60 years: (Add Listeria coverage)

  • Ceftriaxone: 2g IV every 12 hours OR Cefotaxime: 2g IV every 6 hours
  • PLUS Amoxicillin: 2g IV every 4 hours 2

For Suspected Penicillin-Resistant Pneumococci

• Add one of the following:
  • Vancomycin: 15-20 mg/kg IV every 12 hours 2
  • OR Rifampicin: 600 mg IV/oral every 12 hours 2

Pediatric Dosing

Children (1 month to 18 years)

• Ceftriaxone: 50-100 mg/kg/day (not to exceed 4g daily) 2, 3
  • For meningitis: 100 mg/kg on day 1, then 80-100 mg/kg once daily 3, 4
• Cefotaxime: 75 mg/kg every 6-8 hours (200-300 mg/kg/day) 2, 5
• Vancomycin: 10-15 mg/kg every 6 hours (when needed for resistant strains) 2

Neonates (<1 month)

• Age <1 week: Cefotaxime 50 mg/kg every 8 hours 2
• Age 1-4 weeks: Cefotaxime 50 mg/kg every 6-8 hours 2
• Plus Ampicillin/Amoxicillin: 50 mg/kg every 8 hours (age <1 week) or 50 mg/kg every 6 hours (age 1-4 weeks) 2, 6

Treatment Duration

• Meningococcal meningitis: 5 days (if recovered) 2
• Pneumococcal meningitis: 10 days (if recovered by day 10) or 14 days (if not recovered by day 10 or resistant strains) 2, 1
• Listeria meningitis: 21 days 5

Alternative Treatments

• For cephalosporin allergy:
  • Chloramphenicol: 25 mg/kg IV every 6 hours 2
• For Listeria coverage in patients with penicillin allergy:
  • Co-trimoxazole: 10-20 mg/kg (of trimethoprim component) in four divided doses 2

Special Considerations

1. Penicillin-resistant pneumococci:

   • For both penicillin and cephalosporin resistance, use triple therapy:
     • Ceftriaxone/Cefotaxime + Vancomycin + Rifampicin 2

2. Administration notes:

   • Ceftriaxone should be administered over 30 minutes in adults and 60 minutes in neonates 7
   • Do not mix ceftriaxone with calcium-containing solutions 7

3. Dosing in renal impairment:

   • For creatinine clearance ≤50 mL/min: Reduce dose to 50% of normal 8
   • For hemodialysis patients: Give 100% of dose after each dialysis 8

Practical Application

When treating bacterial meningitis, the choice of empiric therapy should be based on:

1. Patient age (neonates, children, adults <60, adults ≥60)
2. Local resistance patterns
3. Recent travel to areas with high antimicrobial resistance

The most recent evidence suggests that for penicillin-susceptible S. pneumoniae meningitis, a once-daily ceftriaxone regimen (2g every 24 hours) may be as effective as twice-daily dosing, provided the organism is highly susceptible to ceftriaxone 9. However, until more definitive evidence emerges, the standard recommendation remains twice-daily dosing for initial treatment.

Remember that cerebrospinal fluid drug levels should be at least 10-fold higher than the MICs of the bacterial isolates for effective treatment 4. This is typically achieved with the recommended dosing regimens.