What is the treatment regimen for meningitis using meropenem (antibiotic)?

Meropenem Treatment Regimen for Bacterial Meningitis

Meropenem is recommended at a dose of 2g IV every 8 hours for the treatment of bacterial meningitis, particularly in cases involving gram-negative bacilli that produce extended-spectrum β-lactamases or hyperproduce lactamases. 1, 2

Indications for Meropenem in Meningitis

• Meropenem is FDA-approved for the treatment of bacterial meningitis caused by Haemophilus influenzae, Neisseria meningitidis, and penicillin-susceptible isolates of Streptococcus pneumoniae in pediatric patients 3 months of age and older 3
• It serves as an alternative to third-generation cephalosporins (cefotaxime or ceftriaxone) with similar clinical and microbiological outcomes 1, 2
• Particularly valuable for treating meningitis caused by gram-negative bacilli that produce extended-spectrum β-lactamases (ESBLs) or hyperproduce lactamases (e.g., Enterobacter species, Citrobacter species, or Serratia marcescens) 1, 4
• Should be considered in patients who have recently returned from areas with high ESBL prevalence or who have ESBL organisms cultured from other sites 1

Dosing Recommendations

• For adults with bacterial meningitis: 2g IV every 8 hours 2, 5
• For pediatric patients: 40 mg/kg IV every 8 hours (up to maximum of 6g/day) 3
• Treatment duration depends on the pathogen:
  • 10 days for pneumococcal meningitis 1
  • 5 days for meningococcal meningitis 1
  • 21 days for Enterobacteriaceae infections 2
  • If no pathogen is identified, treatment can be stopped after 10 days if the patient has clinically recovered 1

Advantages Over Other Carbapenems

• Meropenem has a lower seizure risk compared to imipenem, making it safer for CNS infections 1, 2
• In clinical trials, no patients experienced seizures during meropenem therapy for meningitis, even at doses up to 6g/day 5
• Unlike imipenem, which showed a 33% seizure rate in one pediatric meningitis study, meropenem is considered safe for meningitis treatment 1

Efficacy Data

• Clinical cure rates of 100% have been reported in evaluable adult patients with bacterial meningitis treated with meropenem, compared to 77% with cephalosporin treatment 5
• FDA data shows clinical cure rates of 78% for meropenem versus 77% for comparator antibiotics in bacterial meningitis 3
• Pathogen-specific cure rates include:
  • S. pneumoniae: 71% with meropenem versus 63% with comparators 3
  • H. influenzae (β-lactamase-producing): 80% with meropenem versus 100% with comparators 3
  • N. meningitidis: 86% with meropenem versus 90% with comparators 3

Limitations and Considerations

• For pneumococcal meningitis caused by highly penicillin- and cephalosporin-resistant strains, meropenem may not be effective 1, 2
• In a study of 20 cefotaxime-resistant S. pneumoniae isolates, 4 were intermediate and 13 were resistant to meropenem 1
• Dexamethasone (10 mg IV every 6 hours) should be started on admission, either shortly before or simultaneously with antibiotics, and continued for 4 days if pneumococcal meningitis is confirmed 1
• Hearing loss is a potential sequela of bacterial meningitis regardless of treatment choice, with similar rates between meropenem and comparator antibiotics 3

Outpatient Therapy Considerations

• Outpatient antibiotic therapy (OPAT) may be considered after initial inpatient treatment if the patient:
  • Is afebrile and clinically improving
  • Has received at least 5 days of inpatient therapy
  • Has reliable IV access
  • Can access medical advice/care 24 hours a day
  • Has no other acute medical needs 1

Conclusion for Clinical Practice

Meropenem represents an effective alternative to third-generation cephalosporins for bacterial meningitis, with particular value in treating gram-negative meningitis with suspected resistance. Its lower seizure potential compared to imipenem makes it the preferred carbapenem for CNS infections. For standard community-acquired meningitis cases, third-generation cephalosporins remain first-line, with meropenem reserved for specific situations involving resistant organisms.