Analgesic effects of nonsteroidal antiinflammatory drugs, acetaminophen, and morphine in a mouse model of bone cancer pain

Osamu Saito1, Tomohiko Aoe1 and Tatsuo Yamamoto1

(1) Department of Anesthesiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan

Received: 14 October 2004 Accepted: 16 March 2005

Abstract
Purpose Bone metastasis is one of the major causes of cancer-related pain, and not all bone cancer pain can be effectively treated. Recently, a mouse model of bone cancer pain was introduced. To test the analgesic effects of nonsteroidal antiinflammatory drugs on bone cancer pain, the authors examined the effects of oral administration of a cyclooxygenase-1 (COX-1) selective inhibitor (SC560), a COX-2 selective inhibitor (celecoxib), and a nonselective COX inhibitor (indomethacin) on bone cancer pain and compared these effects to the effect of orally administered acetaminophen and morphine.
Methods An animal model of bone cancer pain was induced by injecting osteolytic murine sarcoma cells in the mouse femur. Drugs were administered orally 2 weeks after tumor-cell implantation, and the level of bone cancer pain was assessed 30, 60, 90, 120, and 180 min after drug administration.
Results Oral administration of acetaminophen, indomethacin, and morphine, but not of SC560 or celecoxib, produced an analgesic effect on bone cancer pain. Co-administration of a subanalgesic does of morphine with acetaminophen enhanced the analgesic effect of acetaminophen.
Conclusion These data suggest that bone cancer pain is effectively treated by oral administration of indomethacin, acetaminophen, and morphine and that the co-administration of acetaminophen and an opioid provides a beneficial effect when treating of bone cancer pain.
Key words Cancer pain - COX - Acetaminophen - Morphine