Fibromyalgia Symptoms are reduced by low-dose naltrexone: A pilot study.

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Fibromyalgia Symptoms are reduced by low-dose naltrexone: A pilot study.

Pain Medicine (2009)

Jarred W. Younger and C. Mackey

What is fibromyalgia?

People with fibromyalgia complain of chronic pain in the muscles of their body.

They are also often profoundly fatigued, and have difficulty sleeping well.

Headaches, stomach problems, and a number of other symptoms are frequently

reported. Millions of people in the United States meet the criteria for

fibromyalgia, and the condition seems to affect more women than men. The

disorder can be debilitating, as the pain and fatigue prevent the individual

from carrying out their normal activities. There are three FDA-approved

medications for fibromyalgia, but not all individuals respond well to those

treatments.

What is low-dose naltrexone?

We tested a medication called low-dose naltrexone (LDN). Naltrexone is a

medication that has been used for many years to treat opioid addiction. When

given at a smaller dose (usually 4.5mg), the drug may help to reduce pain

associated with inflammatory and autoimmune conditions, such as multiple

sclerosis and Crohn's disease. LDN is not FDA-approved for the treatment of

pain, and is still experimental. LDN capsules are typically taken once per day.

What was the study?

We ran a small study to see if individuals with fibromyalgia would receive

benefit from taking LDN. Ten women were enrolled in the study – all of whom met

the criteria for fibromyalgia. The participants were given a handheld computer

to record their pain, fatigue, and other symptoms on a daily basis. They filled

out the daily report for two weeks before receiving capsules. Then they received

capsules to take once daily. The participants received placebo for two weeks,

and then LDN for 8 weeks. The study was single-blind, so participants did not

know when they were receiving placebo or LDN. Finally, participants stopped

taking the capsules and continued to fill out the daily reports for two more

weeks.

Did the drug work?

We were very encouraged by the results. In six out of ten participants, LDN was

significantly better than placebo at reducing fibromyalgia symptoms. LDN reduced

daily pain, the highest level of pain, fatigue, and stress. Other symptoms, such

as sleep problems, gastrointestinal complaints, and headaches, also seemed to be

helped.

Pain Medicine (2009). Overall, self-reported, daily fibromyalgia symptoms (scale

0 – 100, with 100 being most severe symptoms). Time periods are: baseline,

placebo, LDN, and washout. The data are separated into drug responders (solid

line, 6 people) and drug nonresponders (broken line, 4 people). Drug responders

are individuals who had at least a 30% greater reduction of symptoms during LDN

versus placebo.

What were the side-effects?

We did not observe any serious side-effects during the course of the study. The

most commonly reported side-effect (reported by 2 participants) was more vivid

dreams. All of the participants who started the study finished the entire

14-week protocol.

Who was involved?

This study was conducted by lead investigator Jarred Younger, PhD and

Mackey, MD, PhD. Both investigators are in the Department of Anesthesia,

Division of Pain Management at the Stanford University School of Medicine in

Palo Alto, CA. The experiment was conducted at the School of Medicine. The

capsules were prepared by Preuss Pharmacy in Menlo Park, CA.

How did you fund the study?

We were fortunate to have a number of donors that supported this work. Because

naltrexone is a generic drug (in other words, not owned by a pharmaceutical

company), it is difficult to secure funds to test the drug. We received critical

financial support from a gift given by Jim and Connie Binns. We also received

financial and logistical support from the American Fibromyalgia Syndrome

Association (AFSA), a not-for-profit organization that specializes in funding

studies of fibromyalgia treatments. The Oxnard Foundation provided additional

support for the study.

We are currently seeking additional funding to support our continued

investigation into the efficacy of low-dose naltrexone for fibromyalgia and

other conditions. If you are interested in supporting our research please

contact us at snapl@...

Are there any warnings?

We recognize that chronic pain hugely impacts not only patients but their

families and friends as well. Often people seek out the newest research and

treatments in the hopes of reducing their pain and suffering. While we are

excited about the results of this study, we believe some cautions are in order

in interpreting our results. This study was very small; only ten fibromyalgia

patients were tested. Therefore, the results must be replicated on a larger

scale, with more people. There are also a number of questions to be answered

regarding proper dosing, interactions with other medications, and whether or not

beneficial effects are maintained over a long period of time.

Consequently, this study should not be interpreted to suggest that LDN is a

well-accepted treatment for fibromyalgia pain and fatigue. Although we are

pleased with the results of this pilot trial, it is still too early to say how

effective LDN will be for individuals not in this study.

What's next?

We are currently running a double-blind trial and are enrolling participants for

that study. We expect that study to be finished by the end of 2009. Individuals

with fibromyalgia who are close to Stanford University can participate in the

trial. More information can be found at: http://snapl.stanford.edu/ldn/

We will continue to test LDN and similar medications, as we seek to develop

treatments for chronic pain that are highly effective, easily available, and

have a low incidence of side-effects.

Who should I contact if I have additional quiestions or am interested in

supporting your research?

General inquiries and inquiries regarding financial support of our research

should be directed to snapl@...