Effective communication [Response to article: therapeutic interchange is potential weak link. 2004; 137:21]

At the very core of this issue is the hospital formulary system, with which there are some problems, some of which I have witnessed firsthand, as Mr. [Ian Stewart] has pointed out. On the other hand, there are benefits of the hospital formulary systems that may reduce errors. Characteristically, these formularies, unlike most provincial formularies, limit the number of similar agents (often ACE inhibitors, statins, PPIs, etc.). In part, this benefits house-staff physicians starting out in their careers, and allows them to become familiar with one or two agents in each class. Limiting the number of agents potentially reduces the risk of making a prescribing error and is endorsed in the World Health Organization's document "Guide to Good Prescribing."2 So while the formulary system may pose a problem, as illustrated, it can also reduce the risk of error.