Trial results
AI generated results summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI
According to the results reported on ClinicalTrials.gov, this trial enrolled 45 people in total — 23 received the study drug pyridostigmine and 22 received a placebo (a dummy treatment with no active ingredient). All 45 participants completed the trial. The trial was investigating how pyridostigmine affected the body's ability to take up and use oxygen during exercise, measured using a specialised exercise test called an invasive cardiopulmonary exercise test (iCPET). This type of testing is relevant to ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome), a condition where patients often perform worse on a second exercise test done shortly after the first. The reported data shows the following for the main outcome — the change in peak oxygen uptake (how much oxygen the body was using at maximum effort) between the first and second exercise tests: the pyridostigmine group showed a small increase of 13.3 mL/min, while the placebo group showed a decrease of 40.3 mL/min in women and an increase of 111.8 mL/min in men. For the secondary outcomes, the reported data shows similar patterns across measures of heart function (cardiac output, measured in litres per minute) and heart pressure (right atrial pressure, measured in mmHg), with the pyridostigmine group generally showing smaller changes between the two exercise tests compared to the female placebo group, though the male placebo group figures were notably higher across several measures. No information about why the placebo results were reported separately by sex was included in the submitted data. These are the results as reported to ClinicalTrials.gov. They are not medical advice — always discuss what they mean for you with your doctor.
View full results on ClinicalTrials.gov ↗ · Read the linked publication on PubMed (PMID 35526605) ↗
These are the results as reported to ClinicalTrials.gov, not medical advice. Verify independently with the trial site and discuss what they mean for you with your doctor.
Phase 2 Chronic Fatigue Syndrome Trial, Completed
Who may be able to join
AI generated eligibility summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI
Who might be able to join this trial:
- You have been diagnosed with ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) based on a specific set of recognized medical guidelines called the Institute of Medicine criteria.
- You are already scheduled to have a specific type of exercise heart and lung test called an invasive cardiopulmonary exercise test (iCPET) as part of your normal medical care.
Who may not be able to join:
- You have a BMI (body mass index) over 30, which is generally considered to be in the obese range.
- You have asthma that is not well controlled by medication.
- You have anemia (low red blood cell levels) that is significant enough to fall below a certain threshold.
- You currently have cancer or have been treated for cancer in the past.
- You have a history of scarring or inflammation of the lung tissue (a condition called interstitial lung disease).
- You have a chronic lung condition called COPD (chronic obstructive pulmonary disease).
- You have high blood pressure in the arteries of your lungs (pulmonary hypertension).
- You have heart failure where the heart struggles to pump blood properly (congestive heart failure).
- You have an irregular or abnormal heart rhythm that is currently active.
- You have a problem with one or more of your heart valves.
- You have a history of blocked or narrowed arteries that supply blood to the heart (coronary artery disease).
- You have another health condition that doctors believe could prevent you from safely completing the study (confirm with trial site).
- You are pregnant.
- Your iCPET exercise test results showed that you did not reach a maximum effort level during testing.
- Your iCPET test results showed that your lungs physically limited your ability to exercise.
- Your iCPET test results showed high blood pressure in the lung arteries, either at rest or during exercise.
- Your iCPET test results showed high blood pressure in the lung veins, either at rest or during exercise.
- Your blood pressure dropped and stayed low during or after your iCPET test.
- You had a serious, hard-to-control irregular heart rhythm during or after your iCPET test.
Important: Always verify eligibility with the trial site directly before applying.
Based on publicly available eligibility criteria from ClinicalTrials.gov. Verify directly with the trial site before acting. This is not medical advice.
GP referral letter
Print a one-page summary to share with your doctor.
Trial details
Where this trial is recruiting
Primary endpoints
Change in Peak Oxygen Uptake (Peak VO2) Between the First and Second iCPET
Can't join this trial?
Data last synced from ClinicalTrials.gov: 28 July 2026. Trial status can change. Always verify current status directly with the trial site before making any decision.