From the Guidelines
No, vancomycin and daptomycin are not in the same antibiotic class. Vancomycin is a glycopeptide antibiotic that works by inhibiting cell wall synthesis in gram-positive bacteria by binding to the D-Ala-D-Ala terminus of peptidoglycan precursors. Daptomycin, on the other hand, is a lipopeptide antibiotic that functions by inserting into the bacterial cell membrane, causing rapid depolarization and subsequent inhibition of protein, DNA, and RNA synthesis.
Key Differences
- Mechanism of action: Vancomycin inhibits cell wall synthesis, while daptomycin disrupts cell membrane function.
- Resistance patterns: Vancomycin and daptomycin have different resistance profiles, with vancomycin being more susceptible to resistance development in certain strains of MRSA.
- Dosage and monitoring: Vancomycin requires therapeutic drug monitoring due to its narrow therapeutic window, while daptomycin dosing is weight-based and requires monitoring of creatine phosphokinase levels due to potential muscle toxicity.
Clinical Implications
According to the most recent study 1, vancomycin continues to be the standard of care for most patients with MRSA bacteremia, despite being suboptimal for various reasons. Daptomycin, on the other hand, is the only other antibiotic with a Food and Drug Administration (FDA) indication for the treatment of MRSA bacteremia. The study suggests that higher doses of daptomycin (8-12 mg/kg) may be warranted due to its concentration-dependent bactericidal activity and pharmacokinetic studies suggesting inadequate drug exposure in certain populations.
Recommendations
- Vancomycin and daptomycin should not be considered interchangeable due to their different mechanisms of action, side effect profiles, and resistance patterns.
- The choice between vancomycin and daptomycin should be based on individual patient factors, including the severity of infection, renal function, and potential for resistance development.
- Therapeutic drug monitoring and careful dosing are crucial to ensure optimal outcomes and minimize toxicity with both vancomycin and daptomycin, as recommended by the study 1.
From the FDA Drug Label
Daptomycin belongs to the cyclic lipopeptide class of antibacterials. The FDA drug label does not mention the class of vancomycin, therefore, it does not answer the question of whether vancomycin is in the same class as daptomycin.
From the Research
Classification of Vancomycin and Daptomycin
- Vancomycin is classified as a glycopeptide antibiotic 2, 3
- Daptomycin is classified as a cyclic lipopeptide antibiotic, which is a new class of antibiotics 2, 3, 4, 5
Comparison of Vancomycin and Daptomycin
- Both vancomycin and daptomycin have activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci 3, 5
- Daptomycin has a novel mode of action, is rapidly bactericidal in vitro, and has a low potential for the development of resistance 5
- Vancomycin and daptomycin have been compared in clinical trials, with daptomycin shown to be non-inferior to vancomycin for the treatment of complicated skin and skin structure infections (cSSSI) 6
Target Site and Resistance
- Glycopeptides, such as vancomycin, and daptomycin have the same target site, which may lead to reduced susceptibility to both drugs after consecutive use 2
- There is a risk of reduced susceptibility to both vancomycin and daptomycin after consecutive use, and daptomycin should be used with caution for treatment of vancomycin-resistant isolates or after prior vancomycin therapy 2