# Low-Dose Naltrexone for Severe Fibromyalgia Syndrome: A Report of a Case With Two-Year Follow-Up

## TL;DR

A patient with severe fibromyalgia syndrome showed significant improvement after using low-dose naltrexone when standard treatments failed.

## Contribution

This case report provides evidence that low-dose naltrexone may be a viable treatment for severe, treatment-resistant fibromyalgia.

## Key findings

- Low-dose naltrexone (4.5 mg/day) led to significant and sustained improvement in most fibromyalgia symptoms.
- The patient did not benefit from conventional therapies like amitriptyline or pregabalin.
- LDN is suggested as a potential off-label treatment for refractory fibromyalgia.

## Abstract

Fibromyalgia syndrome (FMS) is characterized by diffuse musculoskeletal pain associated with daytime fatigue, sleep disturbance, cognitive deficits, and often further somatic symptoms. While some patients with FMS respond to standard treatment with amitriptyline, pregabalin, or duloxetine in combination with outpatient multimodal pain management, there are still many who do not benefit sufficiently from this treatment or suffer intolerable side effects. Effective treatment options are therefore needed to supplement conventional therapies. Naltrexone is used in many countries as an off-label therapy in low doses for several chronic immunomodulatory disorders, including FMS. However, the strength of evidence from previous randomized controlled trials is low. I report a patient with severe FMS who did not respond to conventional therapy. Instead, low-dose naltrexone (LDN) (4.5 milligrams per day) resulted in a significant and sustained improvement in most FMS symptoms. The results of this case report suggest that an off-label use of LDN in severe refractory FMS may be a viable option. However, the information base is currently limited, and studies are conflicting.