Low dose naltrexone for fibromyalgia: case series demonstrating pain relief and other health benefits.

Fibromyalgia is a chronic pain disorder with multiple proposed etiologies. Pharmacological treatments approved for fibromyalgia are few and not always effective; therefore, some practitioners use off-label medications such as low dose naltrexone (LDN). This case series presents a retrospective chart review of patients who were prescribed LDN for fibromyalgia at an integrative medicine clinic over a 2-year period. Outcomes assessed included pain relief, other health benefits, side effects and prescription habits. Of 10 patients identified, LDN provided substantial pain relief for 8 patients (-4.7/10 points, average -3.75/10 for all 10 patients, p < 0.001). These same patients also reported other important health benefits such better quality of life in 6 patients, reductions in pain flares in 5 patients, improved sleep in 4 patients, improved cognitive functioning in 2 patients, and cessation of other pain medications in 4 patients. Two patients discontinued LDN due to side effects, which in both cases was increased pain. LDN was well tolerated overall, although reported side effects included increased pain, vivid dreams, insomnia and irritability. LDN's proposed mechanism involving hormesis at opioid receptors and its implications for customized dosing in clinical care and research trials are discussed. While not all patients respond to LDN, this medication shows promise as an effective and safe intervention and deserves to be considered as a treatment recommendation for fibromyalgia.