FPGEE for National Association of Boards of Pharmacy (NABP) Practice Exam

How should vancomycin be administered for optimal effectiveness according to its pharmacological profile?

1. In large doses at long intervals

2. In small doses at short intervals

3. As a continuous IV infusion

4. Based solely on patient weight

The correct answer is: In small doses at short intervals

Vancomycin's pharmacological profile indicates that it is critical to maintain effective serum concentrations to ensure its efficacy, particularly because it is a time-dependent antibiotic. Administering vancomycin in smaller doses at shorter intervals allows for more consistent blood levels, reducing the risk of sub-therapeutic concentrations and the potential for treatment failure. This method helps to optimize the drug's action against susceptible organisms, particularly in serious infections such as those caused by methicillin-resistant Staphylococcus aureus (MRSA). In contrast, using large doses at long intervals may lead to peaks and troughs that can fall below the minimum inhibitory concentration (MIC) needed for effectiveness. Continuous IV infusion, while beneficial for some antibiotics, does not align with the pharmacokinetic properties of vancomycin, which requires careful monitoring of serum levels to avoid toxicity and ensure therapeutic effectiveness. Lastly, while adjusting doses based on patient weight is important for calculating appropriate dosages, it should be combined with monitoring serum levels and not used as the sole factor in determining administration intervals. Therefore, administering vancomycin in small doses at short intervals is the optimal choice for achieving and maintaining effective therapeutic levels.