Low-dose naltrexone in fibromyalgia: No pain relief, but memory boost possible

In the treatment of individuals with fibromyalgia, low-dose naltrexone does not appear to help reduce pain but might improve memory instead, as reported in a study.

The study included 99 women (mean age 50.6 years, 99 percent White) who had received a diagnosis of fibromyalgia. These women were randomly assigned to receive low-dose naltrexone (6 mg, n=49) or an identical-appearing placebo (n=50) for 12 weeks.

The primary endpoint of change in pain intensity on an 11-point numeric rating scale as well as safety were assessed in the intention-to-treat population, which consisted of participants who received at least one dose of their allocated intervention. None of the participants were lost to follow-up.

At week 12, the mean change in pain intensity from baseline was –1.3 points (95 percent confidence interval [CI], –1.7 to –0.8) with low-dose naltrexone and –0.9 (95 percent CI, –1.4 to –0.5) with placebo, corresponding to a between-group difference of –0.34 (95 percent CI, –0.95 to 0.27; p=0.27).

Additional data showed that low-dose naltrexone had a signal of benefit for memory problems associated with fibromyalgia.

Adverse events (AEs) occurred in 41 participants in the low-dose naltrexone group (84 percent) and 43 (86 percent) in the placebo group. AEs led to treatment discontinuation in four (8 percent) and three (6 percent) participants in the respective groups. One serious AE occurred in the placebo group, but no deaths occurred.

Further studies are needed to explore the potential of low-dose naltrexone as a memory booster for patients with fibromyalgia.