What antibiotic can be used as an alternative for someone currently on meropenem (Merrem)?

From the Guidelines

Broadening antibiotic coverage beyond meropenem should be done with caution and consideration of the clinical context, suspected pathogens, and local resistance patterns. To broaden coverage, consider adding an antibiotic that targets resistant gram-negative organisms, such as Ceftazidime/avibactam 2.5 g IV q8h 1 or Meropenem/vaborbactam 4 g IV q8h 1, as these combinations have shown efficacy against carbapenem-resistant Enterobacterales (CRE). Some key points to consider when broadening coverage include:

• The patient's clinical syndrome, such as bloodstream infections, complicated urinary tract infections, or complicated intra-abdominal infections, as these may require different treatment approaches 1.
• The use of combination antimicrobial therapy based on susceptibility testing is recommended 1.
• The potential for adverse effects, drug interactions, and antimicrobial resistance with broader coverage, and the need for de-escalation as soon as clinically appropriate based on culture results.
• The choice of antibiotic should be guided by the most recent and highest quality evidence, such as the 2022 guidelines for the treatment of infections due to multidrug-resistant organisms 1. Some other options to consider for broadening coverage include:
• Imipenem/cilastatin/relebactam 1.25 g IV q6h 1
• Polymyxin-based combinations, such as Colistin 5 mg CBA/kg IV loading dose, then 2.5 mg CBA (1.5 CrCl + 30) IV q12h + Tigecycline 100 mg IV loading dose, then 50 mg IV q12h 1
• Aminoglycosides, such as Gentamicin 5-7 mg/kg/day IV QD or Amikacin 15 mg/kg/day IV QD 1.

From the FDA Drug Label

The study evaluated meropenem at doses of 500 mg administered intravenously every 8 hours and imipenem-cilastatin at doses of 500 mg administered intravenously every 8 hours. One controlled clinical study of complicated intra-abdominal infection was performed in the United States where meropenem was compared with clindamycin/tobramycin. Three controlled clinical studies of complicated intra-abdominal infections were performed in Europe; meropenem was compared with imipenem (two trials) and cefotaxime/metronidazole (one trial)

Based on the provided drug labels, imipenem-cilastatin can be considered as an alternative to meropenem. Additionally, cefotaxime/metronidazole and clindamycin/tobramycin were also compared with meropenem in clinical studies for complicated intra-abdominal infections. However, it is essential to note that the choice of antibiotic should be based on the specific clinical scenario, including the type and severity of infection, patient factors, and local resistance patterns. 2 2

• Key considerations:
  • Imipenem-cilastatin has been directly compared to meropenem in clinical trials.
  • Cefotaxime/metronidazole and clindamycin/tobramycin have also been evaluated as alternatives in specific clinical scenarios.
  • The choice of antibiotic should be individualized based on patient-specific factors and local resistance patterns.

From the Research

Broadening Antibiotic Treatment from Meropenem

• Meropenem is a broad-spectrum antibiotic used to treat serious bacterial infections, including those caused by Gram-negative bacteria 3.
• When considering broadening antibiotic treatment from meropenem, it's essential to assess the patient's condition, the causative pathogen, and the antibiotic's spectrum of activity.
• Some studies suggest that combination therapy with meropenem and other antibiotics, such as colistin, may not be superior to monotherapy in treating certain infections, including those caused by carbapenem-resistant Gram-negative bacteria 4.
• However, meropenem has been shown to be effective against a wide range of pathogens, including extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, and is often used as empirical therapy prior to the identification of the causative organism 3.

Alternative Antibiotics

• Based on the available evidence, some alternative antibiotics that may be considered for broadening treatment from meropenem include:
  • Colistin, which has been used in combination with meropenem to treat infections caused by carbapenem-resistant Gram-negative bacteria, although its effectiveness as a combination therapy is still debated 4.
  • Other carbapenems, such as imipenem/cilastatin, which have similar efficacy to meropenem in treating certain infections 3.
  • Cefepime and ceftazidime, which have been used to treat infections caused by Gram-negative bacteria, including those with ESBL-producing organisms 3.

Considerations for Broadening Treatment

• When broadening antibiotic treatment from meropenem, it's crucial to consider the patient's renal function, as meropenem dosing may need to be adjusted based on renal function 5, 6.
• The choice of alternative antibiotic should be guided by the results of antimicrobial susceptibility testing, when available, and the patient's clinical condition 3.
• Therapeutic drug monitoring (TDM) may be useful in optimizing meropenem treatment and preventing adverse effects, particularly in critically ill patients or those with impaired renal function 6.