New tacks to reduce outpatient chemo errors

October 23, 2006

Tracking medication errors in an inpatient hospital setting is fairly common. But what about errors that occur when patients self-administer, or when parents administer drugs to their children at home? Who checks to see if patients are being compliant, or if prescribing errors have been made? Did the family members who are charged with dispensing to children understand the instructions? Or are they doing things doctors and pharmacists are not expecting them to?

Tracking medication errors in an inpatient hospital setting is fairly common. But what about errors that occur when patients self-administer, or when parents administer drugs to their children at home? Who checks to see if patients are being compliant, or if prescribing errors have been made? Did the family members who are charged with dispensing to children understand the instructions? Or are they doing things doctors and pharmacists are not expecting them to?

Attempting to answer some of those questions, researchers at Children's Hospital and Regional Medical Center in Seattle commissioned a study, which was published recently in the journal Cancer. The results are quite revealing.

Douglas Hawkins, M.D., associate professor of pediatrics at Children's Hospital and Regional Medical Center and coauthor of the study, said most of the prescribing errors were due to rounding. "The prescribing errors were a result of people rounding in such a way that the dose was off by more than 10%, and in some cases it was off by more than 11% or 12%." Hawkins said that the 10% rule has been used to determine inpatient chemo errors and was therefore applied to the outpatient setting. "If there is any deviation of greater than 10% from the intended delivery of a medication, we call that an error."

Two recommendations emerged from the study that may help to reduce prescribing errors in the future: adopting a cosignature on all outpatient chemo orders and implementing computerized physician order entry (CPOE). Hawkins noted that the cosignature rule has been used successfully on the inpatient side.

Study authors concluded that by linking CPOE to a standardized dosing table for chemotherapy agents by body surface area, dose miscalculation could be reduced. However, Winter contends that at this stage, CPOE is a strategy that will most likely be implemented down the road. "The current CPOE system is not a safe system to write prescriptions for chemotherapy. However, there are plans in the works to develop a more user-friendly system, and so far the demo looks promising." Winter added that certain safeguards have to be put in place before CPOE is ready for pediatric application.

Description of prescribing errors

Indicated Prescribed and medication dose* administered medication*

Mercaptopurine, 112 mg daily Mercaptopurine, 100 mg daily

Mercaptopurine, 25 mg daily Mercaptopurine, 50 mg daily Monday–Thursday; 25 mg daily Friday–Sunday

Methotrexate, 10 mg weekly Methotrexate, 12.5 mg weekly

Dexamethasone, 2.5 mg A.M., Dexamethasone, 2 mg BID 2 mg P.M.

Dexmethasone, 2.5 mg BID Dexmethasone, 2.5 mg every A.M.; 2 mg every P.M.

Source: University of Washington Child Health Institute/American Cancer Society

*Unless indicated, there was no variance in dosing frequency and duration of treatment indicated/prescribed and duration of medication administration.