Clinical Decision Support Improves Initial Dosing and Monitoring of Tobramycin and Amikacin

Purpose—Clinical decision support (CDS) systems could be valuable tools in reducing aminoglycoside prescribing errors. We evaluated the impact of CDS on initial dosing, interval, and pharmacokinetic outcomes of amikacin and tobramycin therapy. Methods—A complex CDS advisor to provide guidance on initial dosing and monitoring, using both traditional and extended interval dosing strategies, was integrated into computerized provider order entry (CPOE) and compared to a control group which featured close pharmacy monitoring of all aminoglycoside orders. A random sample of 118 patients from an academic, tertiary care medical center prescribed amikacin and tobramycin prior to advisor implementation was compared to 98 patients admitted following advisor implementation. Primary outcome was an initial dose within 10% of a dose calculated to be adherent to published dose guidelines. Secondary outcomes were a guideline-adherent interval, trough and peak concentrations in goal range, and incidence of nephrotoxicity. Results—Of 216 patients studied, 97 were prescribed amikacin and 119 were prescribed tobramycin. The primary outcome of initial dosing consistent with guideline-based care increased from 40% in the pre-advisor arm to 80% in the post-advisor arm (p<0.001), with a number needed to treat of 3 patients to prevent one incorrect dose. Correct initial interval based on renal function also increased from 63% to 87% (p<0.001). The changes in initial dosing and interval resulted in an increase of trough concentrations in the goal range from 59% pre-advisor to 89% post-advisor implementation (p=0.0004). There was no significant difference in peak concentrations in goal range or incidence of nephrotoxicity (25% vs. 17%, p=0.2). Corresponding Author: Zac Cox, Lipscomb University College of Pharmacy, One University Park Drive, Nashville, TN 37204, Office: 615-966-7107, Fax: 615-966-7163, zac.cox@lipscomb.edu. NIH Public Access Author Manuscript Am J Health Syst Pharm. Author manuscript; available in PMC 2012 April 1. Published in final edited form as: Am J Health Syst Pharm. 2011 April 1; 68(7): 624–632. doi:10.2146/ajhp100155. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript Conclusion—An advisor for aminoglycoside dosing and monitoring integrated into CPOE significantly improves initial dosing, selection of interval, and trough concentrations at goal compared to unassisted physician dosing.