Multicenter drug use evaluation of tamsulosin and availability of guidance criteria for nonformulary use in the veterans affairs health system.

Abstract

OBJECTIVE: The U.S. Department of Veterans Affairs (VA) Pharmacy Benefits Management Strategic Healthcare Group (PBM-SHG) and its Medical Advisory Panel developed national criteria (guidelines) for the appropriate use of tamsulosin in the VA. Drug use evaluation (DUE) was performed to (a) determine the prescribing patterns (indications and patient follow-up monitoring as measured by a clinician.s note regarding evaluation of therapeutic response or report of adverse drug event) of tamsulosin, (b) assess the impact of the availability (not active dissemination) of national criteria for nonformulary use of tamsulosin, and (c) project the cost avoidance if generic terazosin was substituted for tamsulosin in those patients who were prescribed tamsulosin outside of appropriate use criteria. METHODS: Geographically dispersed VA medical centers were identified for which tamsulosin utilization was significantly above and below the national average (4.8% of all prescriptions for alpha [alpha]-blockers) in January 2001. A data collection form for medical record abstraction was designed to capture the patient.s diagnosis, reported indication for tamsulosin, history of previous alpha-blocker use, tamsulosin follow-up evaluation, and the individual facility.s method of implementation of criteria for nonformulary use. Patients receiving a prescription for tamsulosin during a 3-month period preceding the posting of national criteria, and patients with a first-time prescription for tamsulosin during a 3-month period after the national criteria were posted were randomly selected by the PBM and assigned for chart review at each site. RESULTS: Data for 332 patients were collected from 6 different sites over a 6-month period for each pregroup and postgroup beginning August 2001 and January 2002, respectively. Tamsulosin was prescribed for appropriate indications in 66% of patients, potentially appropriate indications in 4% of patients, and inappropriate indications in 30% of patients. Of the 206 patients (62%) who were prescribed tamsulosin as a result of a reported adverse event with a previous alpha-blocker, only 29% of the cases (N = 59) showed evidence that an attempt was made to reduce the dose of the first alpha-blocker to abate the side effects. Followup monitoring was conducted in 78% of tamsulosin patients, of whom 55% reported effectiveness of tamsulosin, and 6% reported side effects attributable to tamsulosin. No meaningful differences in prescribing patterns were found between the pregroups and postgroups relative to the posting of the criteria for nonformulary use. Two sites had some form of the criteria made available to physicians, while 4 sites had not implemented the national criteria. Extrapolation of the results to the VA system-wide yielded a conservative estimate of 480,993 dollars in potential cost avoidance for 1 quarter (July to September 2002) when corrected for patients prescribed tamsulosin outside of the criteria for nonformulary use. CONCLUSIONS: Despite the availability of national criteria for nonformulary use of tamsulosin, the results reveal that these criteria were not followed by prescribers. The DUE reinforced the need for more effective implementation and dissemination of criteria for appropriate use of tamsulosin. A formal education process is necessary to encourage appropriate use of formulary alpha-blockers and to attenuate the increased cost associated with the inappropriate prescribing of the nonformulary drug.