Completed

Low-dose Naltrexone for Post-COVID Fatigue Syndrome Treatment

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Study Aim

This study aims to evaluate the effectiveness of low-dose Naltrexone in reducing fatigue intensity, measured by a change in the Fatigue Severity Scale (FSS) total score, in individuals experiencing Post-COVID Fatigue Syndrome.

What is being tested

Low-Dose Naltrexone

+ Placebo

DrugOther
Who is being recruted

COVID-19+22

+ Neuroinflammatory Diseases

+ Post-Acute COVID-19 Syndrome

From 19 to 69 Years
See all eligibility criteria
How is the trial designed

Treatment Study

Placebo-ControlledPhase 2
Interventional
Study Start: January 2024
See protocol details

Summary

Principal SponsorLuis Nacul
Last updated: March 21, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: January 15, 2024

Actual date on which the first participant was enrolled.

This study focuses on a condition known as 'Post-COVID Fatigue Syndrome' (PCFS), a state where individuals don't recover fully after a COVID-19 infection, experiencing persistent fatigue and other symptoms similar to chronic fatigue syndrome. This condition can be triggered by viral infections, with COVID-19 being a potential cause. Currently, there's no evidence-based treatment for PCFS. However, a low-dose of a drug called Naltrexone (LDN) has shown promise in managing similar symptoms in non-COVID cases due to its anti-inflammatory and pain-relieving properties. This study aims to find an effective and safe treatment for PCFS, an urgent need considering the impact of the COVID-19 pandemic and the potential increase in long-term disability associated with this condition. The study is a double-blind, randomized trial involving individuals aged 19-69. Participants will receive either LDN or a placebo in the form of daily oral capsules for 16 weeks. The primary outcome measured will be a change in the Fatigue Severity Scale (FSS) total score by 4.7 points or more. This scale is used to evaluate the intensity of fatigue experienced by the participants. The safety and effectiveness of LDN in managing PCFS symptoms will be assessed, providing valuable insights into a potential treatment for this condition.

Official TitleA Double Blind Randomized Trial of Low-dose Naltrexone for Post-COVID Fatigue Syndrome
NCT05430152
Principal SponsorLuis Nacul
Last updated: March 21, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

160 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Treatment Study

These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.



Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

From 19 to 69 Years

Range of ages for which participants are eligible to join.

Healthy volunteers not allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

COVID-19Neuroinflammatory DiseasesPost-Acute COVID-19 SyndromePost-Infectious DisordersChronic DiseaseCoronaviridae InfectionsEncephalomyelitisInfectionsLung DiseasesMuscular DiseasesMusculoskeletal DiseasesNervous System DiseasesNeuromuscular DiseasesPathologic ProcessesPneumoniaPneumonia, ViralRespiratory Tract DiseasesRespiratory Tract InfectionsRNA Virus InfectionsPathological Conditions, Signs and SymptomsVirus DiseasesFatigue Syndrome, ChronicCoronavirus InfectionsDisease AttributesNidovirales Infections

Criteria

Inclusion Criteria: 1. Male and female patients ages 19 to less than 70 years 2. Case of SARS-CoV-2 over 3 previously, confirmed by a positive test result or clinical confirmation by a physician 3. Meet the clinical diagnostic criteria for PCFS 4. Agree to maintain any other regular medications at current doses for the duration of the trial (except for essential need of new medication or dose change, as prescribed by a physician) 5. Agree to use effective contraception for the trial duration, as appropriate, if female. 6. The participant resides within the delivery area for the drug as determined by FedEx Clinical Trial Services Exclusion Criteria: 1. Pregnant, planning to become pregnant, or breastfeeding 2. Opioid medications: * Any use within last 15 days, as reported by the patient * During the trial 3. A positive urine test for opioids (only for the first 16 participants) 4. History of alcohol, opioid or other substance misuse 5. Participation in another interventional clinical trial in the last 30 days or planned during the trial period 6. Confirmed ME/CFS or FM existing prior to SARS-CoV-2 infection 7. Allergy to naltrexone or medication components 8. Acute hepatitis, liver failure, or severe kidney failure. 9. Current or recent use of naltrexone in the last 30 days 10. The participant is not an ideal candidate for the study, in the opinion of the investigator, for any other reason (ie. personal or logistic, medication, condition, etc.) that could impact the participant's safety or the results of the study. Opioid Washout Period: Potential participants who are currently taking opioid medications who wish to enrol the study will be instructed they can stop taking opioid medications for 15 days before continuing the screening process. They will be instructed that they should speak with their family doctor before stopping any prescribed medications. Positive Urine Test for Opioids: As regular use of opioid medications is an exclusion criterion, we will do a quality control check with the first 16 participants to test for the presence of opioids in their urine. Any participants with a positive test, will be excluded from the study, and such finding will be discussed at the Trial Steering Committee or DSMB for potential trial modification.

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

50% chance of being blinded to the placebo group

Treatment Groups

Group I

Experimental
The Low-Dose Naltrexone (LDN) will be provided as a compounded capsule starting at a strength of 1mg/day of naltrexone and increasing up to a maximum of 4.5 mg/day. The compounding pharmacy will compound the needed doses in Capsugel® empty gelatin based capsules using Naltrexone Hydrochloride Tablets and CELLULOSE.

Group II

Placebo
Matching placebo capsule will be created by compounding pharmacy to look exactly like the LDN doses. The compounding pharmacy will compound the placebo in Capsugel® empty gelatin based capsules using CELLULOSE.

Study Objectives

Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 1 location

Suspended

Women's Health Research Institute

Vancouver, CanadaOpen Women's Health Research Institute in Google Maps
CompletedOne Study Center
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