Vancomycin Prescribing Habits – Are We Still Afraid of Mississippi Mud?

Background Debates over the safety and efficacy of vancomycin have plagued clinical practice for more than half a century. A recent paradigm shift has occurred as the science of PK-PD has encouraged the use of optimized regimens which achieve targeted exposures. However, change is slow and we suspect prescribing habits may not be in line with this consensus approach. Herein, using data from electronic decision support software (EDSS), we describe clinicians’ vancomycin prescribing habits. Methods Data obtained over a 20-month period from an EDSS included: 1) clinician demographics; 2) patient demographics; 3) clinician-selected antimicrobials; and 4) EDSS suggested PK-PD optimized antimicrobial regimens. A vancomycin regimen was considered to be PK-PD optimized if the EDSS provided percent probability of PK-PD target attainment (PTA) was ≥90%. Results Data for 87 clinicians and 104 vancomycin-treated cases were available. Of all clinicians, 62% were clinical pharmacists, 38% were physicians, with close to half of being ID specialists. Of all the clinicians, 55% had ≥10 years of clinical experience. Of the 104 cases, the median (min, max) patient age, weight and creatinine clearance were 43.5 (23, >90) years, 81.6 (47.6, 170.6) kg, and 100.2 (7.3, 188.1) mL/min/1.73 m2, respectively. For 61.5% of selected vancomycin regimens, PTA were ≥90%. The distribution of PTA for the remaining 38.5% of cases is shown in Figure 1. Among these 38.5%, an alternative optimized regimen was presented 97.5% of the time. Further evaluation of clinician demographics among cases with a PK-PD optimized regimen demonstrated that 61% had ≥ 10 years clinical experience while only 44% of those who did not chose a PK-PD-optimized regimen had the same experience. While the majority of clinicians in both the optimized and non-optimized groups were clinical pharmacists, ID physicians represented 55% of all physicians who chose a non-optimized vancomycin regimen. Conclusion Data obtained from an EDSS demonstrated that clinicians who chose a non-optimized vancomycin regimen had less experience than those who chose an optimized regimen. Data suggest that education for optimizing vancomycin dosing using PK-PD is needed as part of antimicrobial stewardship training initiatives. Disclosures S. M. Bhavnani, ICPD Technologies: Shareholder, stock options. C. M. Rubino, ICPD Technologies: Shareholder, stock options. P. G. Ambrose, ICPD Technologies: Shareholder, stock options.