Therapeutic substitution of cimetidine for nizatidine was not associated with an increase in healthcare utilization.

Objective: To examine changes in healthcare utilization resulting from a formulary switch to cimetidine from nizatidine at the Veterans Affairs Pittsburgh Healthcare System.
Study Design: A retrospective analysis of administrative and clinical data 6 months before and 6 months after the therapeutic substitution.
Methods: The 704 patients who were switched from nizatidine to cimetidine were included in the study. Administrative data included total and primary care clinic visits, emergency room visits, gastrointestinal (GI)-related radiological studies, and GI endoscopic procedures. Discharge summaries were examined, and rates of total and GI-related hospitalizations were calculated.
Results: There was no evidence of increased utilization of healthcare resources during the 6 months after the formulary switch. Estimated monthly pharmaceutical savings for the Veterans Affairs Pittsburgh Healthcare System were $7260.
Conclusions: A formulary switch from nizatidine to cimetidine can be accomplished at significant pharmaceutical cost savings, and this retrospective study suggests that this can be done without increasing other aspects of healthcare resource utilization.