Seven percent of adults and 19 percent of children taking chemotherapy drugs in outpatient clinics or at home were given the wrong dose or experienced other mistakes involving their medications, according to a new study led by Kathleen E. Walsh, MD, assistant professor of pediatrics at the University of Massachusetts Medical School, and published in the January 1, 2009 issue of the Journal of Clinical Oncology.

“As cancer care continues to shift from the hospital to the outpatient setting, the complexity of care is increasing, as is the potential for medication errors, particularly in the outpatient and home settings,” said Dr. Walsh, who is also a Robert Wood Johnson Physician Faculty Scholar.

An analysis of data on nearly 1,300 patient visits at three adult oncology outpatient clinics and 117 visits at one pediatric facility between September 1, 2005 and May 31, 2006 showed that errors in medication were more common than previously reported by oncology patients

Of the 90 medication errors involving adults, 55 had the potential to harm the patient and 11 did cause harm. The errors included administration of incorrect medication doses due to confusion over conflicting orders — one written at the time of diagnosis and the other on the day of administration.

Patients were also harmed by over-hydration prior to administration of medication, resulting in pulmonary edema and recurrent complaints of abdominal pain and constipation. More than 50 percent of errors involving adults were in clinic administration, 28 percent in ordering of medications, and 7 percent in use of the drugs in patients’ homes.

Walsh suggests that writing orders on the day of chemotherapy would be one way to avoid some of these errors.

“Requiring that medication orders be written on the day of administration, following review of lab results, may be a simple strategy for preventing errors among adults, while most of the errors involving children may have been avoided by better communication and support for parents of children who use chemotherapy medications at home,” said Dr. Walsh.

The study, “Medication Errors among Adults and Children with Cancer in the Outpatient Setting,” was supported in part by the US Health and Human Services Agency for Healthcare Research and Quality through its Centers for Education and Research on Therapeutics program.