Effects of clinical decision support and pharmacist prescribing authority on a therapeutic interchange program

Results of an evaluation of therapeutic interchange (TI) program outcomes with use of prescriber alerts alone or in combination with pharmacist prescribing are reported.

A retrospective single-center study was conducted to compare TI outcomes before incorporation of prescriber alerts encouraging formulary agent use into the electronic medical record (period 1), after alert implementation (period 2), and after implementation and expansion of TI protocols including pharmacist prescribing authority (period 3). The evaluation focused on TI orders for 3 drug classes: angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (HMG-CoA RIs). The primary outcome was formulary medication utilization.

In total, 2,881, 2,700, and 3,088 prescriptions for medications in the ACEI, ARB, or HMG-CoA RI class were ordered during periods 1, 2, and 3, respectively. Overall formulary adherence improved from 78.3% in period 1 to 97.6% in period 2 and 99.2% in period 3 (p < 0.001 for both comparisons with period 1). The percentages of inappropriate dosing conversions were 51.6%, 37.2%, and 2.4% in periods 1, 2, and 3, respectively; the corresponding percentages of inappropriate discharge medications were 64.5%, 16.3%, and 2.4%.

Percentages of formulary medications in 3 medication classes, considered separately and together, increased with the implementation of TI alerts for prescribers and the addition of TI-related pharmacist prescribing authority. Over the same study periods, percentages of inappropriate dosing conversions and inappropriate discharge medications decreased.