ABSTRACT
Background: Naltrexone has been approved for alcohol and opioid abuse by the FDA. At low-dose naltrexone (LDN) has been used in several diseases including chronic pain and autoimmune conditions, including rheumatic disorders. Aim: To review the use of LDN in rheumatic diseases: systemic sclerosis (SSc), dermatomyositis (DM), Sjögren's syndrome (SS), rheumatoid arthritis (RA), and fibromyalgia (FM). Methods: PubMed and Embase databases were searched for articles on LDN and rheumatic diseases between 1966 and August 2022. Results: Seven studies in FM have been identified: in this disease LDN has showed beneficial effects on pain and well-being. In SS, two articles with 3 cases description showed that LDN may be of help in the pain treatment. LDN relieved pruritus in scleroderma (a case description with a series of 3 patients) and dermatomyositis (description of 3 patients in two articles). In RA a study using Norwegian Prescription Database showed that LDN was associated to reduction in the use of analgesic and DMARDs. No serious side effects were detected. Conclusion: This review shows that LDN is a promising and safe therapy to be used in some rheumatic disease. However, the data is limited and needs to be reproduced in larger studies.
ABSTRACT
Naltrexone (NTX) is an opioid antagonist that inhibits cell proliferation in vivo when administered in low doses. Naltrexone in low doses can reduce tumor growth by interfering with cell signalling as well as by modifying the immune system. It acts as an Opioid Growth Factor receptor (OGFr) antagonist and the OGF-OGFr axis is an inhibitory biological pathway present in human cancer cells and tissues, being a target for the treatment with naltrexone low-dose (LDN). Clinical trials have proposed a unique mechanism(s) allowing LDN to affect tumors. LDN shows promising results for people with primary cancer of the bladder, breast, liver, lung, lymph nodes, colon and rectum. This short review provides further evidence to support the role of LDN as an anticancer agent.