Potential pathophysiological role of the ion channel TRPM3 in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and the therapeutic effect of low-dose naltrexone

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating disease with a broad overlap of symptomatology with Post-COVID Syndrome (PCS). Despite the severity of symptoms and various neurological, cardiovascular, microvascular, and skeletal muscular findings, no biomarkers have been identified.

The Transient receptor potential melastatin 3 (TRPM3) channel, involved in pain transduction, thermosensation, transmitter and neuropeptide release, mechanoregulation, vasorelaxation, and immune defense, shows altered function in ME/CFS. Dysfunction of TRPM3 in natural killer (NK) cells, characterized by reduced calcium flux, has been observed in ME/CFS and PCS patients, suggesting a role in ineffective pathogen clearance and potential virus persistence and autoimmunity development.

TRPM3 dysfunction in NK cells can be improved by naltrexone in vitro and ex vivo, which may explain the moderate clinical efficacy of low-dose naltrexone (LDN) treatment. We propose that TRPM3 dysfunction may have a broader involvement in ME/CFS pathophysiology, affecting other organs. This paper discusses TRPM3’s expression in various organs and its potential impact on ME/CFS symptoms, with a focus on small nerve fibers and the brain, where TRPM3 is involved in presynaptic GABA release.

Source: Löhn M, Wirth KJ. Potential pathophysiological role of the ion channel TRPM3 in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and the therapeutic effect of low-dose naltrexone. J Transl Med. 2024 Jul 5;22(1):630. doi: 10.1186/s12967-024-05412-3. PMID: 38970055; PMCID: PMC11227206. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11227206/ (Full Text)

Low-Dose Naltrexone Improves post-COVID-19 condition Symptoms

Abstract:

Purpose: Treatments for myalgic encephalomyelitis and chronic fatigue syndrome can be adapted for post-COVID-19 condition. Our aim was to compare treatments in patients from our post-COVID-19 clinic.

Methods: We conducted a retrospective cohort study and included consecutive patients enrolled in our post-COVID-19 clinic. We included patients who received low-dose naltrexone, amitriptyline, duloxetine, and physical therapy, and evaluated improvements in fatigue, pain, dyspnea, and brain fog recorded in the electronic health record. We calculated the adjusted relative hazard of improvement using Cox proportional models. We adjusted for demographic characteristics, comorbidities, and prior COVID-19 hospitalization.

Findings: We included the first 108 patients with post-COVID-19 enrolled in the clinic. Most of the patients received amitriptyline. The relative hazard of improvement for those taking low-dose naltrexone was 5.04 (95% CI, 1.22-20.77; P = 0.02) compared with physical therapy alone. Both fatigue and pain were improved in patients taking low-dose naltrexone; only fatigue was improved in patients taking amitriptyline.

Implications: Post-COVID-19 condition symptoms may improve in patients taking medications adapted from myalgic encephalomyelitis and chronic fatigue syndrome. Randomized controlled trials should evaluate these medications and translational studies should further evaluate their mechanisms of action.

Source: Tamariz L, Bast E, Klimas N, Palacio A. Low-Dose Naltrexone Improves post-COVID-19 condition Symptoms. Clin Ther. 2024 Jan 23:S0149-2918(24)00003-1. doi: 10.1016/j.clinthera.2023.12.009. Epub ahead of print. PMID: 38267326. https://pubmed.ncbi.nlm.nih.gov/38267326/

Low-dose naltrexone use for the management of post-acute sequelae of COVID-19

Abstract:

The global prevalence of Post-Acute Sequelae of SARS-CoV-2 Infection (PASC) stands at approximately 43 % among individuals who have previously had acute COVID-19. In contrast, in the United States, the National Center for Health Statistics (NCHS) estimates that around 11 % of individuals who have been infected with SARS-CoV-2 go on to experience long COVID. The underlying causes of PASC remains under investigation, and there are no currently established FDA-approved therapies.

One of the leading hypotheses for the cause of PASC is the persistent activation of innate immune cells with increase systemic inflammation. Naltrexone is a medication with anti-inflammatory and immunomodulatory properties that has been used in other conditions that overlap with PASC.

We performed a retrospective review of a clinical cohort of 59 patients at a single academic center who received low-dose naltrexone (LDN) off-label as a potential therapeutic intervention for PASC. The use of LDN was associated with a fewer number of symptoms, improved clinical symptoms (fatigue, post-exertional malaise, unrefreshing sleep, and abnormal sleep pattern), and a better functional status. This observation warrants testing in rigorous, randomized, placebo-controlled clinical trials.

Source: Bonilla H, Tian L, Marconi VC, Shafer R, McComsey GA, Miglis M, Yang P, Bonilla A, Eggert L, Geng LN. Low-dose naltrexone use for the management of post-acute sequelae of COVID-19. Int Immunopharmacol. 2023 Oct 5;124(Pt B):110966. doi: 10.1016/j.intimp.2023.110966. Epub ahead of print. PMID: 37804660. https://www.sciencedirect.com/science/article/pii/S1567576923012912 (Full text)

Efficacy of Low-Dose Naltrexone and Predictors of Treatment Success or Discontinuation in Fibromyalgia and Other Chronic Pain Conditions: A Fourteen-Year, Enterprise-Wide Retrospective Analysis

Abstract:

Current pharmacologic treatments may provide limited analgesia in fibromyalgia and other chronic pain disorders. Low-dose naltrexone (LDN) has emerged as a potential analgesic option that has been minimally explored.

This study aims to describe current real-world prescribing practices of LDN, to investigate if patients have a perceived benefit of LDN in treating pain symptoms and to identify predictors associated with a perceived benefit or discontinuation of LDN.

We evaluated all outpatient prescriptions for LDN prescribed for any pain indication in the Mayo Clinic Enterprise from 1 January 2009 to 10 September 2022. A total of 115 patients were included in the final analysis.

The patients were 86% female, had a mean age of 48 ± 16 years, and 61% of prescriptions were for fibromyalgia-related pain. The final daily dose of oral LDN ranged from 0.8 to 9.0 mg, while the most common dose was 4.5 mg once daily.

Of patients who reported follow-up data, 65% reported benefit in their pain symptoms while taking LDN. Adverse effects were reported in 11 (11%) patients and 36% discontinued taking LDN by the most recent follow-up.

Concomitant analgesic medications were used by 60% of patients and were not associated with perceived benefit nor discontinuation of LDN, including concomitant opioids.

LDN is a relatively safe pharmacologic option that may benefit patients with chronic pain conditions and warrants further investigation in a prospective, controlled, and well-powered randomized clinical trial.

Source: Driver CN, D’Souza RS. Efficacy of Low-Dose Naltrexone and Predictors of Treatment Success or Discontinuation in Fibromyalgia and Other Chronic Pain Conditions: A Fourteen-Year, Enterprise-Wide Retrospective Analysis. Biomedicines. 2023; 11(4):1087. https://doi.org/10.3390/biomedicines11041087 https://www.mdpi.com/2227-9059/11/4/1087 (Full text)

Safety and efficacy of low dose naltrexone in a long covid cohort; an interventional pre-post study

Abstract:

Background: Up to 37.7% of patients experience symptoms beyond 12 weeks after infection with SARS-CoV-2. To date care for people with long covid has centred around multidisciplinary rehabilitation, self care and self pacing. No pharmacotherapy has been shown to be beneficial.

Methods: In this single centre interventional pre post study, the safety of Low Dose Naltrexone (LDN) was explored in patients with Post COVID-19 Syndrome (PCS), defined by NICE as patients with ongoing symptoms 12 or more weeks after initial infections with SARS-CoV-2 where alternative explanation for symptoms cannot be found. Patients were recruited through a Post COVID clinic, had a baseline quality of life questionnaire in symmetrical Likert format, were prescribed 2 months (1 mg month one, 2 mg month two) of LDN and repeated the same questionnaire at the end of the second month. Patients were monitored to adverse events.

Findings: In total 52 patients participated of whom 40(76.9%) were female. The median age was 43.5 years(IQR 33.2–49). Healthcare workers represented the largest occupational cohort n = 16(34.8%). The median time from diagnosis of COVID-19 until enrolment was 333 days (IQR 171–396.5). Thirty-eight participants (73.1%) were known to commence LDN, two of whom (5.3%) stopped taking LDN post commencement due to new onset diarrhoea and also described fatigue. In total 36(69.2%) participants completed the questionnaire at the end of the two-month period. Improvement was seen in 6 of 7 parameters measured; recovery from COVID-19, limitation in activities of daily living, energy levels, pain levels, levels of concentration and sleep disturbance (p ≤ 0.001), improvement in mood approached but was not significant (p = 0.054).

Conclusions: LDN is safe in patients with PCS and may improve well-being and reduce symptomatology in this cohort. Randomised control trials are needed to further explore this.

Source: Brendan O’Kelly, Louise Vidal, Tina McHugh, James Woo, Gordana Avramovic, John S. Lambert. Safety and efficacy of low dose naltrexone in a long covid cohort; an interventional pre-post study. Brain, Behavior, & Immunity – Health; Volume 24, October 2022, 100485 https://www.sciencedirect.com/science/article/pii/S2666354622000758  (Full text)

Low-dose naltrexone as a treatment for chronic fatigue syndrome

Abstract:

Naltrexone is used as an off-label treatment in low doses for several chronic immune-modulated disorders in many countries. Although only small-scale clinical trials have been performed, these suggest efficacy in several diseases including Crohn’s disease, fibromyalgia and Gulf War Illness. Despite numerous internet reports of response to low-dose naltrexone (LDN), no clinical trials exist in people with chronic fatigue syndrome. This condition is characterised by chronic profound fatigue, postexertional malaise, pain and autonomic and neurocognitive disturbances.

This series of three case reports compiled by people with long-term ill-health due to chronic fatigue syndrome shows the range of responses they observed when taking LDN, from life changing to a reduction in some symptoms only. Treatment doses ranged from 4 to 12 mg. Clinical trials may be warranted to explore the potential use of naltrexone in people with these debilitating illnesses which currently have no licensed treatments available.

Source: Bolton MJ, Chapman BP, Van Marwijk H. Low-dose naltrexone as a treatment for chronic fatigue syndrome. BMJ Case Rep. 2020 Jan 6;13(1). pii: e232502. doi: 10.1136/bcr-2019-232502. https://www.ncbi.nlm.nih.gov/pubmed/31911410

Low-dose naltrexone in the treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

Background: Myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is a common medical condition that limits physical and cognitive functions, with no known effective medical treatment.

Methods: We report on the safety and effectiveness data accumulated in clinical practice when treating ME/CFS with low-dose naltrexone (LDN, 3.0 – 4.5 mg/day). The medical records from 218 patients who received ar diagnosis of ME/CFS and LDN treatment during 2010–2014 were retrospectively analyzed.

Results: Outcome data were available in 92.2% of patients with an average follow-up time of 1.7 years. A positive treatment response to LDN was reported by 73.9% of the patients. Most patients experienced improved vigilance/alertness and improved physical and cognitive performance. Some patients reported less pain and fever, while 18.3% of patients did not report any treatment response to LDN. Mild adverse effects (insomnia, nausea) were common at the beginning of the treatment. Neither severe adverse effects nor long-term adverse symptoms were reported.

Conclusions: The high frequency of treatment response and good safety profile observed in this retrospective open label study could prompt prospective controlled studies to confirm the feasibility of LDN in alleviating ME/CFS symptoms.

Source: Olli Polo, Pia Pesonen & Essi Tuominen (2019) Low-dose naltrexone in the treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), Fatigue: Biomedicine, Health & Behavior, DOI: 10.1080/21641846.2019.1692770 https://www.tandfonline.com/doi/full/10.1080/21641846.2019.1692770