{"id":5370,"date":"2020-05-06T09:48:16","date_gmt":"2020-05-05T23:48:16","guid":{"rendered":"https:\/\/doseme-rx.com\/?p=5370"},"modified":"2021-04-13T16:54:59","modified_gmt":"2021-04-13T06:54:59","slug":"dosing-guidelines-for-physicians","status":"publish","type":"post","link":"https:\/\/doseme-rx.com\/es\/vancomycin\/articles\/dosing-guidelines-for-physicians","title":{"rendered":"Take the Opportunity to Steward Vancomycin with Release of New Dosing Guidelines"},"content":{"rendered":"\n

The 2020 vancomycin monitoring guidelines <\/a>were released in March during the COVID-19 pandemic response and therefore under the radar of many physicians.<\/p>\n\n\n\n

They recommend a shift away from vancomycin trough levels <\/a>to Area Under the Curve (AUC), in relation to the minimum inhibitory concentration (MIC) in adults, pediatrics, and neonates.<\/p>\n\n\n\n

This dosing approach is recommended for patients with serious infections due to methicillin resistant Staphylococcus aureus <\/em>(MRSA). <\/p>\n\n\n\n

There are a number of studies demonstrating the clinical impact associated with inappropriate vancomycin dosing in many patients with MRSA infections utilizing trough levels alone, particularly ICU patients with renal insufficiency and obesity.<\/p>\n\n\n\n

When vancomycin levels are suboptimal, treatment failures can occur due to isolates that have intermediate susceptibility to vancomycin or isolates that are resistant to vancomycin.<\/p>\n\n\n\n

When dosing is too high, patients risk vancomycin-induced nephrotoxicity, which ranges from 5 to 43% with a relative risk of 2.45 (95% Confidence Interval: 1.69-3.55) based on clinical studies.<\/p>\n\n\n\n

Vancomycin dosing based on AUC:MIC is now therefore recommended as the optimal dosing and monitoring method for the treatment of serious MRSA infections.<\/p>\n\n\n\n

Dosing by AUC:MIC (as determined by broth microdilution) with a goal of 400-600 mg-hr\/Liter should keep vancomycin concentration at therapeutic levels needed to achieve a clinical response, but below levels that might increase the risk of nephrotoxicity.<\/p>\n\n\n\n

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Methods of Calculating AUC:MIC<\/strong><\/h3>\n\n\n\n
\"vancomycin-dosing-physician's-perspective\"<\/figure>\n\n\n\n
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Bayesian Dosing Approach<\/strong><\/h4>\n\n\n\n

Methods of calculating AUC include an equation-based methodology or a Bayesian approach<\/a>, which utilizes population data to calculate a patient\u2019s pharmacokinetics.<\/p>\n\n\n\n

The Bayesian method, available through commercially available software programs, allows for precision dosing by creating an individualized, dynamic model of dosing vancomycin for every patient that can be updated over time as more patient specific information (e.g. vancomycin levels, serum creatinine) is received.<\/p>\n\n\n\n

According to the new 2020 vancomycin dosing guidelines<\/a>, the preferred approach to monitoring AUC is through these programs. This recommendation was given an A-III GRADE. Bayesian software programs can utilize drug levels obtained earlier in therapy (e.g. 24-48 hours) because it is not required that a patient\u2019s vancomycin levels be stable, otherwise known as \u201csteady state\u201d. <\/p>\n\n\n\n

One recent study<\/a> documented the transition from conventional trough-based vancomycin dosing to AUC based dosing (targeting an AUC of at least 400) at four adult hospitals. A Bayesian analysis of a subgroup of AUC and trough guided patients in this study indicated that vancomycin exposure was significantly higher in the trough guided dosing group. The authors concluded that AUC-guided dosing resulted in lower daily vancomycin doses and lower trough and AUC values. From a safety standpoint, AUC-guided dosing of vancomycin was associated with reduced nephrotoxicity, which appeared to be a result of reduced vancomycin exposure.<\/p>\n\n\n\n

First Order Kinetic Calculations<\/strong><\/h4>\n\n\n\n

Another method that can be utilized to calculate AUC is by using \u201cfirst order\u201d kinetic calculations. Practically speaking, to make patient-specific adjustments to the vancomycin dose, two vancomycin levels within the same dosing interval are needed.<\/p>\n\n\n\n

Unlike Bayesian dosing, this methodology requires patients to be at steady state when the levels are drawn.<\/p>\n\n\n\n

The first level is obtained 1-2 hours after the end of the infusion (the peak) and the second level should be obtained prior to the next dose. With this information, a calculation can be made to adjust subsequent doses of vancomycin. Monitoring<\/a> is recommended for patients with serious MRSA infections, but also all patients at high risk for nephrotoxicity (e.g., critically ill patients receiving concurrent nephrotoxic therapy), patients with unstable renal function, and those receiving prolonged courses of therapy (> 3 to 5 days).<\/p>\n\n\n\n

Frequency of monitoring is based on clinical judgment but general recommendations are outlined:<\/p>\n\n\n\n