Metformin for Fibromyalgia Symptoms (INFORM Trial)

The main purpose of the project is to evaluate the safety and efficacy of low dose metformin for improving symptoms associated with fibromyalgia syndrome (FMS) via modulating neuroinflammatory pathways. The investigators hypothesize that FMS patients in the low-dose metformin conditions will show greater improvement in FMS symptoms than those who are in the placebo group. Further, the investigators hypothesize that metformin will increase phosphorylated AMPK in peripheral immune cells of FMS patients and will decrease the transcription of mTORC1, NLRP3 inflammasome, and nociceptive cytokines interleukin 1beta and interleukin 18.

Fibromyalgia syndrome (FMS) is a chronic pain condition that is debilitating to an estimated 10 million Americans and results in high utilization of medical resources with a cost of over $100 billion in health care and lost productivity each year. It is widely accepted that chronic widespread pain is a defining feature of FMS and that it is maintained by central sensitization. Accumulating evidence demonstrates that central sensitization is driven, at least in part, by neuroinflammation. Thus, molecules that ameliorate the causes of neuroinflammation are intriguing candidates to treat FMS symptoms. Current therapies are only partially effective in about 50% of patients. The development of a treatment approach with better efficacy is urgently needed. The investigators propose to test the use of metformin for FMS. This drug is widely used as a first line treatment for type II diabetes. Metformin causes the phosphorylation of AMP-activated protein kinase (AMPK), which regulates key enzymes and transcription factors that modulate gene expression involved in metabolism and inflammation. Because AMPK acts as a master switch kinase, this target may prove particularly effective in treating the many diverse symptoms of FMS. Indeed, metformin treated hyperalgesia in preclinical models of neuropathic, inflammatory, spinal cord injury and diabetes-induced mechanical hyperalgesia and reduced symptoms of anxiety, depression and cognitive dysfunction. This is of significant relevance because these symptoms contribute greatly to FMS patient disability. The investigators expect that this study will determine the effectiveness of metformin on pain and comorbidity FMS symptoms and delineate the role that AMPK and its downstream targets play on these phenotypes. The investigators anticipate that these results will demonstrate the efficacy of an intervention not currently used clinically to treat FMS. Understanding these pathways represents a critical step in the development of non-addictive pain treatments and holds enormous potential to reduce disability in the 10 million Americans with FMS.