A "substantially growing number of patients" are being injured or killed by the prescription drugs they are taking under doctors' orders, according to a new report from the Institute for Safe Medication Practices.

Reuters reported Sept. 10 that researcher Thomas Moore and colleagues said that reports of such deaths and injuries have more than doubled between 1998 and 2005, largely due to problems with painkillers and immune-system boosters.

Drug-related deaths increased from 5,519 in 1998 to 15,107 in 2005. Overall reports rose from 34,966 to 89,842 during the same period -- a rate four times greater than the growth in outpatient prescriptions.

"This growing toll of serious injury shows that the existing system is not adequately protecting patients and underscores the importance of recent reports urging far-reaching legislative, policy and institutional changes," they wrote.

The researchers based their conclusions on data reported by drug makers to the U.S. Food and Drug Administration. Congress is currently considering legislation that would increase such surveillance.

The findings appear in the Archives of Internal Medicine.