Symptom Response to Low-Dose Naltrexone in Fibromyalgia: An Exploratory Analysis of the Randomized Placebo-Controlled FINAL Trial.

BACKGROUND

Fibromyalgia (FM) remains difficult to manage due to a highly variable symptom profile. The "FINAL" randomized, placebo-controlled trial examined the efficacy of low-dose naltrexone (LDN) on pain in women with FM, showing no significant difference in pain reduction at the group level but potentially higher 30% pain response rates. Analysis of secondary outcomes showed potential improvements in memory problems.

OBJECTIVES

This exploratory analysis aimed to further investigate individual responses to LDN treatment by analyzing 30% responder rates for six secondary FM outcomes.

METHODS

The FINAL trial included 99 women with FM who were randomized 1:1 to treatment with LDN or placebo for 12 weeks. Based on original data from this trial, 30% response rates were assessed for the six selected secondary outcomes: tenderness, fatigue, sleep disturbances, depression, memory problems, and stiffness. Risk ratios (RR) with 95% confidence intervals (CI) were calculated to assess differences between groups.

RESULTS

No significant differences were found between treatment groups for any of the symptom response categories. The highest RR was observed for memory (RR = 1.67, 95% CI: 0.82-2.95), followed by sleep (RR = 1.28, 95% CI: 0.92-2.64), stiffness (RR = 1.26, 95% CI: 0.84-2.89, p = .47), tenderness (RR = 1.16, 95% CI: 0.88-2.67), fatigue (RR = 1.10, 95% CI: (0.78-3.13) and depression (RR = 0.96, 95% CI: 0.92-2.66).

CONCLUSIONS

Response rates for 30% improvement in six selected nonpain outcomes were similar after 12 weeks treatment with LDN or placebo in women with FM. Larger studies investigating 30% response rates are warranted.