Drug Critieria & Outcomes

Most pediatric chemo errors affect patients

Researchers have found that the majority of chemotherapy errors for children with cancer affect the patients. They also found the errors are more often caused by dispensing or administration mistakes than by prescribing mix-ups.

The study, published in the journal Cancer, led by Marlene Miller, MD, associate professor of pediatrics at the Johns Hopkins School of Medicine, Baltimore, found that 85% of the drug errors were not noticed until the child receive the medication. While not all the errors harm the patients, the authors said, they always are worrisome.

Miller and her colleagues obtained their data by analyzing Medmarx, the United States Pharmacopeia's voluntary medication error reporting database. They found that prescribing errors accounted for only 10% of cases in patients under age 18 from 1999-2004. Rather, most of the mistakes arose from dispensing errors by pharmacy staff or administration problems involving nurses and other health care workers.

A total of 310 chemotherapy errors for pediatric patients from 69 different institutions were found in the review of Medmarx data. More than 80% of the errors reached the patients, meaning they were not caught before the drug was administered, and about 16% required an escalation of care, Miller said.

Most errors (48%) involved mistakes in drug administration, with another 30% being errors in dispensing. The most commonly cited types of error were mistakes in dose or quantity (23%), or time of administration (23%), followed by failing to deliver the drug at all (14%) and improper administration technique or route (12%). The biggest cause of error was listed as "performance deficit," a nice way of saying "human error," which came in at 41%.

Miller said children are more susceptible to medication errors than adults because there is no "usual" dose for children since pediatric doses generally vary with body size. She said the problem is even greater for anticancer medications because they are very potent drugs and their therapeutic window is narrow. "I can give four times the normal dose of Motrin and you will be fine," Miller told the news media. "You cannot do that for chemo; they have a very narrow safety window."

She said that while many hospitals use computer systems to compute proper dosages in hopes of reducing errors, the systems often don't cover chemotherapy agents because the rules for dosing and protocols for administering the drugs are constantly being revised as new clinical trial data appear.

Miller said her study cannot be considered as having reported the actual rate of chemotherapy errors. To calculate that number, she said, one would need to know the total number of chemotherapy doses administered. Also, since Medmarx is a voluntary database, some errors go unreported.

"It is impossible to be vigilant on everything, to never make an error, never be late," she said. "So our struggle is to introduce something to make it more error-free.