Provider and pharmacist responses to warfarin drug-drug interaction alerts: a study of healthcare downstream of CPOE alerts.
OBJECTIVE
To categorize the appropriateness of provider and pharmacist responses to warfarin critical drug-drug interaction (cDDI) alerts, assess responses and actions to the cDDI, and determine the occurrence of warfarin adverse drug events (ADE) after alerts.


METHODS
An 18-month, retrospective study of acute care admissions at a single Veterans Affairs medical center using computerized provider order entry (CPOE).


METHODS
Patients included had at least one warfarin cDDI alert. Chart reviews included baseline laboratory values and demographics, provider actions, patient outcomes, and associated factors, including other interacting medications and number of simultaneously processed alerts.


RESULTS
137 admissions were included (133 unique patients). Amiodarone, vitamin E in a multivitamin, sulfamethoxazole, and levothyroxine accounted for 75% of warfarin cDDI. Provider responses were clinically appropriate in 19.7% of admissions and pharmacist responses were appropriate in 9.5% of admissions. There were 50 ADE (36.6% of admissions) with warfarin; 80% were rated as having no or mild clinical effect. An increased number of non-critical alerts at the time of the reference cDDI alert was the only variable associated with an inappropriate provider response (p=0.01).


CONCLUSIONS
This study was limited by being a retrospective review and the possibility of confounding variables, such as other interacting medications.


CONCLUSIONS
The large number of CPOE alerts may lead to inappropriate responses by providers and pharmacists. The high rate of ADE suggests a need for improved medication management systems for patients on warfarin. This study highlights the possibility of alert fatigue contributing to the high prevalence of inappropriate alert over-ride text responses.
Department of Pharmaceutical Services, University of California San Francisco, San Francisco, California 94143, USA. allison.miller@ucsfmedctr.org
Allison M
AM
Miller
Maureen S
MS
Boro
Nancy E
NE
Korman
J Ben
JB
Davoren
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000075202:Contraindications; D004347:Drug Interactions; D004360:Drug Therapy, Computer-Assisted; D006787:Hospitals, Veterans; D006801:Humans; D007223:Infant; D008297:Male; D050316:Medical Order Entry Systems; D008505:Medical Staff, Hospital; D008875:Middle Aged; D010595:Pharmacists; D017010:Reminder Systems; D012189:Retrospective Studies; D014481:United States; D014859:Warfarin / Q000009:adverse effects
D014859:Warfarin