A novel glial cell inhibitor, low dose naltrexone, reduces pain and depression... (Abstract)

A novel glial cell inhibitor, low dose naltrexone, reduces pain and depression, and improves function in chronic pain: A CHOIR study

J Pain
01 April 2016

Low-dose naltrexone (LDN), 4.5 mg naltrexone hydrochloride, has efficacy in treating symptoms of fibromyalgia in clinical trials. LDN is an inexpensive drug with infrequent and mild side effects. One proposed mechanism for LDN’s efficacy is through attenuation of the production of proinflammatory cytokines and neurotoxic superoxides via suppressive effects on central nervous system microglia cells. A number of chronic pain conditions (e.g. fibromyalgia, complex regional pain syndrome, migraine headache, interstitial cystitis) are thought to represent a “central sensitivity syndrome”. Additionally, there is a need to know if LDN improves symptoms in “real world patients.” Therefore, we used our Collaborative Health Outcomes Information Registry (CHOIR) to determine whether LDN improves pain, fatigue, sleep, mood, or physical function in chronic pain patients. Patients were administered CHOIR surveys at each visit to the Stanford Pain Management Clinic. In this study, 27 patients with chronic “central” pain states who were given a first-time prescription of LDN were followed. A retrospective chart review was performed to confirm continued use of LDN at Time 1 (scores gathered between 31 and 60 days after LDN prescription) and Time 2 (scores gathered between 61 and 90 days after LDN prescription). Wilcoxon Signed Rank Test (WSRT) analyses suggested that patients taking LDN reported significantly lower average pain scores, lower “lowest” pain scores, and improved physical function from baseline to Time 2 (p < 0.05). Depression scores were also significantly reduced from baseline to Time 1 and from baseline to Time 2 (p < 0.05). The significant findings of decreased average pain scores and depression and improved physical function after prescribing this well tolerated, inexpensive medication provides justification for larger, controlled trials in patients with central sensitivity syndromes.