Survey of pharmacists' and physicians' perceptions of therapeutic interchange.

Therapeutic interchange has long been an integral part of drug formulary management, but physicians' and pharmacists' attitudes toward such programs are relatively unknown. This survey was undertaken to determine pharmacists' attitudes, physicians' potential response to a hypothetical interchange, and how well pharmacists predicted physicians' responses. A survey that described a drug interchange program and several potential responses to the proposed switch was provided to 300 staff physicians at a 512-bed community facility in southwest Florida; the survey was also mailed to pharmacy directors or clinical pharmacy coordinators at 42 southwest Florida hospitals. Responses were obtained from 98 physicians and 95 pharmacists. Most physicians would not cooperate with an interchange if they were not familiar with the proposed drug; 16% would continue to prescribe the original drug, knowing that the new agent would be provided; and 58% would switch to another agent with which they had clinical experience. Only 26% of physicians would follow the interchange program. In contrast, 48% of pharmacists believed that physicians would continue to order the original therapy, 32% believed that physicians would order the new agent, and only 20% believed that physicians would switch to an alternative drug (P<.005 vs physician responses). Clearly, pharmacists' expectations of physicians' response to a therapeutic interchange differ significantly from the physicians' expected behavior. This difference has potentially important implications for actual versus projected cost savings of therapeutic interchange.