Are meropenem and meropenem-vaborbactam (meropenem-cilastatin) the same?

Meropenem vs Meropenem-Vaborbactam: Not the Same Medications

No, meropenem and meropenem-vaborbactam are not the same medications. Meropenem-vaborbactam is a combination drug that contains meropenem (a carbapenem antibiotic) plus vaborbactam (a beta-lactamase inhibitor), while meropenem is a standalone carbapenem antibiotic 1.

Key Differences

• Composition:

  • Meropenem: Single agent carbapenem antibiotic 2
  • Meropenem-vaborbactam: Combination of meropenem with vaborbactam, a boron-based β-lactamase inhibitor 1

• Mechanism of Action:

  • Vaborbactam has no antibacterial activity on its own but inhibits Ambler class A (KPC) and class C β-lactamases, enhancing meropenem's effectiveness against certain resistant organisms 1
  • Vaborbactam does not inhibit class B or D β-lactamases 1

• Clinical Applications:

  • Meropenem-vaborbactam is specifically recommended for carbapenem-resistant Enterobacteriaceae (CRE) infections 1, 3
  • Standard meropenem is used for a broader range of serious bacterial infections but may be less effective against CRE 2, 4

Clinical Efficacy

• The TANGO-II trial demonstrated that meropenem-vaborbactam for CRE infections was associated with:

  • Increased clinical cure rates
  • Decreased 28-day mortality (15.6% vs 33.3%) compared to best available therapy
  • Reduced nephrotoxicity 1

• A retrospective study comparing meropenem-vaborbactam with ceftazidime-avibactam for CRE infections found no significant difference in treatment success and 30-day mortality 1

Important Distinctions from Other Combinations

• Do not confuse with imipenem-cilastatin:

  • Imipenem requires cilastatin (a dehydropeptidase-I inhibitor) to prevent renal metabolism 5, 6
  • Meropenem is stable against renal dehydropeptidase-I and does not require cilastatin 5, 6

• Do not confuse with imipenem-cilastatin-relebactam:

  • This is a different carbapenem (imipenem) with its own β-lactamase inhibitor (relebactam) 1
  • Approved for different specific indications 1

Clinical Recommendations

• For standard susceptible infections: Use meropenem alone 2
• For CRE infections: Consider meropenem-vaborbactam 1, 3
• For CRE bloodstream infections: Guidelines specifically recommend meropenem-vaborbactam as a treatment option 1
• For critically ill patients with CRE infections: Extended infusion (3 hours) of meropenem-vaborbactam is recommended 3

Dosing Considerations

• Meropenem standard dosing: 500mg-1g IV every 8 hours 2
• Meropenem-vaborbactam for CRE infections: 4g (contains 2g meropenem + 2g vaborbactam) IV every 8 hours 1
• Both require dose adjustment in renal impairment 5

Remember that these are distinct medications with different indications, particularly for resistant infections, and should not be used interchangeably without consideration of the specific pathogen and resistance patterns.