Reduced Pro-Inflammatory Cytokines after Eight Weeks of Low-Dose Naltrexone for Fibromyalgia

Abstract

Fibromyalgia (FM) is a complex, multi-symptom condition that predominantly affects women. The majority of those affected are unlikely to gain significant symptomatic control from the few treatments that are approved for FM. In this 10-week, single-blind, crossover trial we tested the immune effects of eight weeks of oral administration of low-dose naltrexone (LDN). We enrolled eight women with an average age of 46 years, symptom severity of 62 out of 100, and symptom duration of 14 years. We found that LDN was associated with reduced plasma concentrations of interleukin (IL)-1β, IL-1Ra, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p40, IL-12p70, IL-15, IL-17A, IL-27, interferon (IFN)-α, transforming growth factor (TGF)-α, TGF-β, tumor necrosis factor (TNF)-α, and granulocyte-colony stimulating factor (G-CSF). We also found a 15% reduction of FM-associated pain and an 18% reduction in overall symptoms. The findings of this pilot trial suggest that LDN treatment in fibromyalgia is associated with a reduction of several key pro-inflammatory cytokines and symptoms. The potential role of LDN as an atypical anti-inflammatory medication should be explored further.

Keywords: LDN; cytokine; fibromyalgia; immune; inflammation; low-dose; naltrexone.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1

The average plasma concentrations of each cytokine found to be significantly reduced between baseline (BL) and Drug. On the y-axis, data are presented as the mean and 95% confidence intervals of within-person z-score standardized concentrations, as this provides the most accurate representation of change across the study. The x-axis shows the time in blocks of two weeks, starting with baseline (BL).

Figure 2

The plasma concentrations of TNF-α measured in samples obtained from each participant during the study. On the y-axis, the concentration is shown in pg/mL. On the x-axis, time is shown in weeks with zero signifying the commencement of LDN administration. A linear regression line is fitted to the 0–8 week time period.