Table 2

Inclusion and exclusion criteria

Inclusion criteria	Exclusion criteria
Male and female patients aged 19 to less than 70 years. Case of SARS-CoV-2 over 3 months previously, confirmed by a positive test result or clinical confirmation by a physician. Meet the clinical diagnostic criteria for PCFS (box 1). 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). Agree to use effective contraception for the trial duration, as appropriate (if female). The participant resides within the delivery area for the drug as determined by FedEx Clinical Trial Services.	Pregnant, planning to become pregnant or breast feeding. Use of opioid medications within last 15 days, as reported by the patient or during the trial. A positive urine test for opioids (only for the first 16 participants; see below). History of alcohol, opioid or other substance misuse. Participation in another interventional clinical trial in the last 30 days or planned during the trial period. Confirmed ME/CFS or FM existing prior to SARS-CoV-2 infection. Allergy to naltrexone or medication components. Acute hepatitis, liver failure or severe kidney failure. Current or recent use of naltrexone within 30 days.

Inclusion criteria

Exclusion criteria

Male and female patients aged 19 to less than 70 years.
Case of SARS-CoV-2 over 3 months previously, confirmed by a positive test result or clinical confirmation by a physician.
Meet the clinical diagnostic criteria for PCFS (box 1).
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).
Agree to use effective contraception for the trial duration, as appropriate (if female).
The participant resides within the delivery area for the drug as determined by FedEx Clinical Trial Services.

Pregnant, planning to become pregnant or breast feeding.
Use of opioid medications within last 15 days, as reported by the patient or during the trial.
A positive urine test for opioids (only for the first 16 participants; see below).
History of alcohol, opioid or other substance misuse.
Participation in another interventional clinical trial in the last 30 days or planned during the trial period.
Confirmed ME/CFS or FM existing prior to SARS-CoV-2 infection.
Allergy to naltrexone or medication components.
Acute hepatitis, liver failure or severe kidney failure.
Current or recent use of naltrexone within 30 days.

FM, fibromyalgia; ME/CFS, myalgic encephalomyelitis/chronic fatigue syndrome; PCFS, post-COVID-19 fatigue syndrome.