New data shows patients with chronic low back pain on Cymbalta (duloxetine HCl) maintained reductions in pain for 41 weeks. In patients who initially responded to duloxetine, this maintenance of pain reduction was accompanied by further reduction in pain that was statistically significant as measured by the Brief Pain Inventory (BPI) average pain rating. The data will be presented today at the sixth triennial congress of the European Federation of Chapters of the International Association for the Study of Pain (EFIC(R)).
A total of 181 patients enrolled in the open-label 41-week extension phase of the study, designed to evaluate long-term maintenance of effect in patients with chronic low back pain taking duloxetine 60 mg or 120 mg once daily. Maintenance of effect was assessed in the responders - 58 duloxetine patients who had experienced at least 30 per cent pain reduction from baseline during the 13-week, placebo-controlled acute phase of the study.
The most common adverse events in the study (those occurring in more than 5 per cent of study participants) included headache, nausea, upper abdominal pain, excessive sweating (hyperhidrosis), back pain, diarrhoea and fatigue. Adverse events were similar to those seen in previous duloxetine studies. A total of 18 patients in the study discontinued due to adverse events during the extension phase.
"Chronic low back pain is a painful and debilitating condition and this study is an important step in the fight against it," said Vladimir Skljarevski, lead study author and a neurologist and medical fellow at Lilly Research Laboratories.
Experts estimate chronic low back pain affects between 4 percent and 33 percent of the world's population at any one time. According to the International Association for the Study of Pain (IASP), the pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Chronic pain is defined as pain that persists beyond acute pain or beyond the expected time for an injury to heal. Men and women are equally affected by chronic low back pain, and it occurs most often between the ages of 30 and 50.
Serotonin and norepinephrine in the brain and spinal cord are believed to both mediate core mood symptoms and help regulate the perception of pain. Based on preclinical studies, Cymbalta is a balanced and potent reuptake inhibitor of serotonin and norepinephrine that is believed to potentiate the activity of these chemicals in the central nervous system (brain and spinal cord).