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A New Look at 4 Old Drugs That May Be Effective Fibromyalgia Treatments

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Fibromyalgia Treatment Possibilities

It’s been more than a decade since the U.S. Food and Drug Administration (FDA) has approved any new pharmaceutical treatments for fibromyalgia. While there are at least four new fibromyalgia drugs in the pipeline, it could take years before any of these are available to patients.

In the meantime, the fibromyalgia community desperately needs relief from their daily pain and other symptoms! Fortunately, there are a few researchers who are looking for ways to repurpose older drugs for fibromyalgia.

4 Old Drugs That May Be Effective Fibromyalgia Treatments

These drugs will likely never be the subject of big clinical trials because there’s little profit to be made given their age. However, that doesn’t mean they aren’t effective.

In fact, all of the pharmaceuticals mentioned below perform just as well or better than the three drugs currently approved by the FDA to treat fibromyalgia. But since none of these drugs are considered first-line treatments for fibromyalgia, it does take both an open-minded doctor and patient to give them a try.


FDA approved: 1970

Original use: Surgical anesthesia

A growing number of pain clinics are now offering ketamine infusions for chronic conditions like fibromyalgia, but do they actually work? Early research suggests they may – at least temporarily.

In a small Swedish study, 11 fibromyalgia patients were randomly selected to receive either a low-dose ketamine infusion or a placebo infusion. Eight of those patients experienced at least 50% less pain using ketamine.

“There was a significant reduction in pain intensity with the ketamine infusion compared to the saline infusion during and 20-80 minutes after the test period,” reads a research review. “There was a decrease in tenderness and increased endurance.”

Two additional small studies carried out by some of the same researchers verified that ketamine is effective at reducing fibromyalgia pain. Altogether, 57% of the fibromyalgia patients in these three studies experienced at least a 50% reduction in pain from ketamine infusions.

That finding mirrors what I’ve heard from my readers at Prohealth.com and FedUpwithFatigue.com. Anecdotally, ketamine seems to work really well for fibromyalgia pain, but unfortunately the relief doesn’t last. The pain-relieving benefits of ketamine infusions tend to wear off within a few days or weeks, requiring the ongoing expense of another infusion.

But if someone has the disposable income and seeks temporary relief from their pain, ketamine infusions could definitely be an option.

Another alternative is taking ketamine in pill form.

“The use of oral ketamine for [the] treatment of fibromyalgia has not been widely studied; however, one study reported clinically meaningful responses in a small number of patients,” reads this review.

(Read more: Ketamine infusions for chronic pain | A systematic review and meta-analysis of randomized controlled trials)


FDA approved: 2003

Original use: Alzheimer’s disease

Sometimes the brain fog caused by fibromyalgia literally can feel like early-stage dementia so it isn’t surprising that an Alzheimer’s drug might be helpful in treating fibro.

Memantine is frequently used for moderate-to-severe Alzheimer’s disease, but two small Spanish studies have shown it may benefit those with fibromyalgia, too. In 2014, researchers from the University of Zarogoza reported memantine significantly reduced fibromyalgia pain when administered to 63 patients at a dosage of 20 mg per day.

Five years later, a second study involving some of the same University of Zarogoza researchers found memantine improved cognitive function, depression and illness severity among 10 fibromyalgia patients.

So how does an Alzheimer’s drug improve fibromyalgia symptoms? Patients with fibromyalgia and Alzheimer’s both have been found to have elevated levels of the neurotransmitter glutamate in the brain. Excess glutamate also is associated with increased pain. Memantine works by preventing glutamate from adhering to brain receptors, thereby reducing fibromyalgia symptoms.

(Read more: Alzheimer’s drug shows promise for treating fibromyalgia pain)


FDA approved: 1995

Original use: Type 2 diabetes

One of the biggest fibromyalgia-related news stories during 2019 was a University of Texas study that proposed using metformin, a popular type 2 diabetes drug, as a fibro treatment.

That study has since been retracted by the journal that published it, but the results still hint at a possible link between blood hemoglobin A1c levels and fibromyalgia pain. As part of the study, patients were given 500 mg of metformin twice a day in combination with “standard treatment” of either an antidepressant (amitriptyline, duloxetine or milnacipran) or an anticonvulsant (gabapentin or pregabalin).

“The subgroup of patients who had undergone pharmacological treatment of [insulin resistance] with metformin, in combination with the [standard treatment], experienced a dramatic decrease in pain scores,” reads the study. “Response to metformin plus [standard treatment] was followed by complete resolution of pain in eight of 16 patients who had been treated with metformin, a degree of improvement never observed before in such a large proportion of fibromyalgia patients subjected to any available treatment.

“In contrast, patients treated with [standard treatment] alone improved, but complete resolution of pain was generally not observed,” the study continues. “Interestingly, some patients responded only to metformin and not to [standard treatment] with [antidepressants] or membrane stabilizing agents.”

Although this study was small, the results are definitely promising! After years of reading fibromyalgia research, I believe this is the first time I’ve ever seen a study claim 100% pain relief, so the results definitely caught my attention. Hopefully, the researchers behind the study can fix the issues that caused their work to be retracted and repeat their finding with a new trial.

Low-dose naltrexone

FDA approved: 1984

Original use: Alcohol and drug dependence

Low-dose naltrexone (LDN) is the dark horse of the fibromyalgia community. Very few patients and doctors know about it, and yet I frequently hear from persons with fibromyalgia who say LDN has changed their lives for the better.

An opioid receptor antagonist, naltrexone has been used to treat alcohol and drug dependence since the 1980s at full doses of 50 mg or higher.

At low doses of 1-9 mg, however, “it is hypothesized that [LDN] causes [a] transient blockade of opioid receptors centrally resulting in a rebound of endorphin function which may attenuate pain in fibromyalgia,” reads a 2018 University of Southern California study.

In 2009, then Stanford University researcher Jarred Younger, Ph.D., conducted the first clinical trial of LDN as a fibromyalgia treatment. While the study only involved 10 patients, LDN “reduced fibromyalgia symptoms in the entire cohort, with a greater than 30% reduction of symptoms over placebo,” reads the study. “Side effects (including insomnia and vivid dreams) were rare and described as minor and transient.”

A second, slightly larger Stanford study involving 31 fibromyalgia patients confirmed the results of the initial pilot study.

Since then, a growing number of people are successfully treating their fibro pain with LDN. Anecdotally, I am continually amazed by how well LDN works in some fibromyalgia patients. It’s not unusual for me to hear LDN users say “it’s given my life back to me.”

(Read more: Review of therapeutic utilization of low dose naltrexone)

Now it’s your turn: Have you tried ketamine, memantine, metformin or low-dose naltrexone as a fibromyalgia treatment? Share your experience in the comments below!

Donna Gregory Burch was diagnosed with fibromyalgia in 2014 after several years of unexplained pain, fatigue and other symptoms. She was later diagnosed with chronic Lyme disease. Donna covers news, treatments, research and practical tips for living better with fibromyalgia and Lyme on her blog, FedUpwithFatigue.com. You can also find her on Facebook and Twitter. Donna is an award-winning journalist whose work has appeared online and in newspapers and magazines throughout Virginia, Delaware and Pennsylvania. She lives in Delaware with her husband and their many fur babies.


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By ProHealth-Editor

Karen Lee Richards is ProHealth’s Editor-in-Chief. A fibromyalgia patient herself, she co-founded the nonprofit organization now known as the National Fibromyalgia Association (NFA) and served as its vice-president for eight years. She was also the executive editor of Fibromyalgia AWARE, the very first full-color, glossy magazine devoted to FM and other invisible illnesses. After leaving the NFA, Karen served as the Guide to Fibromyalgia and Chronic Fatigue Syndrome for the New York Times website About.com, and then for eight years as the Chronic Pain Health Guide for The HealthCentral Network.To learn more about Karen, see "Meet Karen Lee Richards."

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