TABLE 3-4 Errors by Community and Mail Order Pharmacies

Community pharmacy: telephoned prescription errors

Percentage of telephoned prescriptions containing an error

12.4 (Camp et al., 2003)

Community pharmacy: dispensing errors

Percentage of prescriptions erroneously dispensed

1.7 (Flynn et al., 2003)

3.4 (Buchanan et al., 1991)

12.5 (Kistner et al., 1994)

24 (Allan et al., 1995)

Mail order pharmacy: dispensing errors

Percentage of prescriptions erroneously dispensed

0.075 (Teagarden et al., 2005)

contained at least one prescription writing error (Shaughnessy and Nickel, 1989). Two studies found high rates of medication errors in ambulatory hemodialysis units (Manley et al., 2003a,b). Extrapolating the findings of the study with the lower rate (Manley et al., 2003a) to the 246,000 U.S. hemodialysis patients, nearly 111,000 medication-related problems occur to these patients each month. In an ambulatory chemotherapy clinic, a medication error rate of 3.0 percent was found (Gandhi et al., 2005). Another study (Dill and Generali, 2000) found a lack of adequate documentation provided with drug samples available for administration to patients in an ambulatory clinic. Finally, three studies (Wagner and Hogan, 1996; Bedell et al., 2000; Ernst et al., 2001) found high rates of medication documentation errors.

Regarding community pharmacies (see Table 3-4), one study (Camp et al., 2003) found that 12.4 percent of telephoned prescriptions contained an error in the information provided by the person calling in the prescription. Four studies examining dispensing errors and using the same error detection method found a wide range of prescription dispensing error rates—1.7 to 24 percent. One study conducted in a hospital-based outpatient pharmacy found the rate of dispensing errors to be 12.5 percent (Kistner et al., 1994). Another small-scale study found a 24 percent dispensing error rate (Allan et al., 1995). In a study at a high-volume outpatient pharmacy, the error rate was found to be 3.4 percent (Buchanan et al., 1991). These three studies published in the period 1991–1995, reported much higher error rates than a more recent study reflecting the likely improvements in dispensing systems and technology over time. This more recent, large-scale study of both new prescriptions and prescription refills found an error rate of 1.7 percent (Flynn et al., 2003). This dispensing error rate translates to approximately 4 errors per 250 prescriptions per pharmacy per day, or an



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