Most Errors in Pediatric Chemo Make It to Patients

TUESDAY, May 29 (HealthDay News) -- The vast majority of potentially harmful errors in chemotherapy for children with cancer do find their way to these young patients, a new study finds. And they are more often caused by dispensing or administration mistakes than by prescribing mix-ups, the researchers found.

In total, 85 percent of these drug errors were not spotted until the child received the medication, according to a study led by Dr. Marlene Miller, associate professor of pediatrics at the Johns Hopkins School of Medicine, Baltimore. These errors do not always cause harm to the child, the authors added, but they are always worrisome.

Their analysis of the United States Pharmacopeia's voluntary medication error-reporting database, MEDMARX, also found that prescribing errors accounted for only 10 percent of cases occurring in patients under 18 years of age from 1999 to 2004. Instead, most of the mistakes arose from dispensing errors by pharmacy staff or administration blunders by nurses and other health care workers.

A total of 310 chemotherapy errors for pediatric patients were logged during the study period, from 69 different institutions. (As of 2004, 616 institutions were participating in the MEDMARX program, up from 56 in 1999.) More than eight out of 10 of these incidents reached the patient, meaning they were not caught prior to administration, and about 16 percent required an escalation of care as a result, Miller said.

Surprisingly, prescribing errors accounted for just one in 10 cases. Most errors (48 percent) involved mistakes in administration, followed by errors in dispensing (30 percent). The most commonly cited types of error were mistakes in dose or quantity (23 percent), or time of administration (23 percent), followed by omission errors (that is, failing to deliver the drug at all, 14 percent) and improper administration technique or route (12 percent). By far the biggest cause of error was "performance deficit" -- human error -- at 41 percent.

The research was published online May 25 in the journalCancer, and is expected to be published in the July 1 print issue.

Children generally are more susceptible to medication errors than adults, Miller said, because unlike with adults, there is no "usual" dose for children; pediatric dosages generally are based on body size.

The problem is even more pronounced for anticancer medications, however, because these drugs are so potent and their so-called therapeutic window is so narrow.

"I can give four times the normal dose of Motrin, and you will be fine," Miller said as an example. "You cannot do that for chemo; they have a very narrow safety window."

Many hospitals use computer systems to compute proper dosages and reduce such errors, but, Miller said, these systems often do not include chemotherapy agents, as the rules for dosing and the protocols for administering the drugs are constantly being revised as new clinical trial data appear.

"The dosing [for chemotherapeutics] is so different, so the vendors haven't built in the logic of how to do this," Miller said. "So, we have lots of interventions and tools to improve patient safety, but chemo falls off the radar screen."

Even when such safety systems are in place, errors can still occur.