Animal Study Questions Use of Morphine for Bone Pain

In mouse model of bone cancer, morphine increases pain and bone loss

FRIDAY, May 5 (HealthDay News) -- A study in mice suggests that sustained morphine exposure may paradoxically increase pain and speed bone loss in patients with metastases, according to research presented this week at the annual meeting of the American Pain Society in San Antonio, Texas.

Anna Vardanyan, M.D., of the University of Arizona in Tucson, and colleagues injected murineosteolytic sarcoma cells into the femurs of mice and sealed them with dental amalgam. After seven days, the researchers treated the mice with either sustained morphine or saline administration through subcutaneous osmotic mini-pumps.

The researchers found that morphine enhanced both sarcoma-induced spontaneous and evoked pain behaviors with a corresponding increase in the expression of pronociceptive neurotransmitters. They also found that morphine increased sarcoma-induced expression of ATF-3, a marker for damaged cells, and accelerated sarcoma-induced bone destruction and increased the rate of spontaneous fracture.

"These data indicate that sustained exposure to morphine enhances bone cancer-induced pain and increases bone loss, raising questions regarding the appropriate treatment for bone cancer pain," the authors conclude.

Abstract (#631)

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