With the publication of the new vancomycin guidelines, pharmacists are going to experience a major change from trough-based monitoring of vancomycin to area under the curve (AUC)-based dosing strategies.

Known as one of the most frequently used antibiotics since the 1950s, vancomycin is intravenous and mostly used in a hospital setting, but can also be used in a home infusion or outpatient setting.

The last update to the guidelines was in 2009, which introduced the concept of dosing based on AUC and established the relationship between the AUC and the minimum inhibitory concentration (MIC) as a “useful pharmacodynamic parameter to predict effectiveness.” Due to the burden of obtaining multiple serum vancomycin levels, along with the challenges of performing AUC mathematical calculations, the guideline authors recommended using a vancomycin trough level for use as a possible surrogate.

According to Kristi Kuper, PharmD, BCPS, the new guidelines will focus on dosing to an AUC, which will be evaluated relative to the minimum inhibitory concentration to measure how susceptible bacteria is to vancomycin. “Trough levels are a poor marker of efficacy and dosing to trough levels has been shown to lead to an increased risk of acute kidney injury,” Kuper said in an interview with Pharmacy Times®.

Kuper recommends that the first step for pharmacists in transitioning is to review the information available and continue to talk with their pharmacy staff to make adjustments based on their hospital’s protocol. Reviewing basic definitions of topics such as pharmacokinetics and pharmacodynamics will also be a helpful resource for pharmacists.

Additionally, pharmacists will need to determine which method they will use to calculate AUC, which can be a difficult process. Kuper explained 2 different major tools that are used to calculate AUC: manual or “hand” calculating, or the Bayesian Clinical Support software, or DoseMeRx.

By hand, the pharmacist would need to gather the proper information and complete a few complex math questions to calculate the AUC. The DoseMeRx program automatically calculates the AUC by using patient specific information, such as serum creatinine, to create an individualized dosing level for that patient.   

The biggest benefit of the new vancomycin guidelines, according to Kuper, is to see the improvement in use of vancomycin in patients. “A challenge in the past in certain patient types is that we would give them these doses, target certain trough level, and think we are doing good because we are giving the dose that would kill the infection,” Kuper said in an interview with Pharmacy Times®. “With a lower dose being given, it will be safer and less of an injury, giving more mileage out of the antibiotic and also the same therapeutic effect.”  

REFERENCE

Kuper, Kristi. Preparing for the New Vancomycin Guidelines- What Should You Be Considering? DoseMe. https://doseme-rx.com/news/20200110-preparing-new-vancomycin-guidelines-what-to-consider. Published January 10, 2020. Accessed March 18, 2020.

Editor's Note: This artcle was updated on March 19, 2020.