Potential effects of rational prescribing on national health care spending: More than half a billion dollars in annual savings.

Objective: To estimate the cost savings that could result from implementation of a rational prescribing model for drug classes that are equivalent in terms of efficacy, toxicity, and convenience.

Design: The top 10 drug classes based on annual spending were gathered from the Canadian Institute for Health Information. They were reviewed for potential inclusion in the study based on the ability to compare intraclass medications.