and colleagues (2004) found that 6.5 percent of overdose and underdose warnings for pediatric patients were inappropriate, and a daily review of pharmacist overrides is now performed to correct problems early in the process. At the medication administration stage, Oren and colleagues (2002) studied overrides of antimicrobial withdrawals from an automated dispensing machine and found that medication errors occurred in 21 percent of cases. Kester (2005) found that 12 percent of overrides were associated with variances from written orders, and 2 percent were related to medication errors or near misses. A unit-based pharmacist can help decrease medication errors resulting from overrides (Haas et al., 2004), and a well-implemented system should include education about the possible implications of overriding system warnings.

Ultimately, it will be important to implement all of the above technologies at the same time and link them electronically. Orders can then be transmitted electronically to the pharmacy, where they can be evaluated and filled. It should be possible to do this for many medications, with manual filling being checked using bar coding for a small minority of medications. The electronic medication record can then be populated. Nurse administration of medications taken orally can be checked through bar coding, while intravenous medications can be screened using smart pumps. All of these techniques should be able to communicate wirelessly. Many of these approaches, especially CPOE and automated dispensing in the pharmacy, will be easier to support in larger, rather than smaller, hospitals. With this combined approach, it might be possible to reduce the medication error rate in hospitals on the order of 100-fold.

In nursing homes, electronic prescribing will likely be important, although there are few data to date regarding its efficacy in this setting, and the key decision support required will likely differ somewhat from that in the inpatient setting (Gurwitz et al., 2005; Rochon et al., 2005). Therefore, CPOE is likely to yield substantial benefits, especially if it can be done remotely, enabling the physician to review the patient’s medication list and perform checks, such as those for drug–drug interactions, in real time (Rochon et al., 2005). This is a particular problem in nursing homes as many residents are taking multiple medications, and most physicians are not located at the site. Nonetheless, implementation of CPOE in this setting will be challenging since most nursing homes have very limited resources, and many have relationships with large numbers of physicians who spend relatively little time at each site.

Bar coding and computerized medication administration records can also be expected to have an impact in this setting. Barker and colleagues