Testing Probenecid against a placebo for chronic pain
Official title: Novel Use of Probenecid to Alleviate Symptoms of Opioid Withdrawal
Novel Use of Probenecid to Alleviate Symptoms of Opioid Withdrawal in People With Chronic Pain Undergoing Voluntary Opioid Tapering: a Pilot Study
- Phase 2
- 3 groups
- One site, in Calgary
- Recruiting
Interventions
- Medication
Probenecid
The Investigators aim to recruit 40 participants who will be followed for 12 weeks in duration. Participants will be randomized in a 2:2:1 ratio to one of probenecid 500 mg, 1000 mg, or placebo PO BID for 12 weeks. Justification for use of a non-active placebo comparator includes the fact that this trial is meant to identify tolerability and safety of probenecid in a population of patients living with chronic pain, this will be best measured by comparing to a non-active placebo.
Canadian Sites (1)
1 of 1 recruiting
- Recruiting
Richmond Road Diagnostic and Treatment Centre
Calgary, Alberta
Eligibility Criteria
See who this study is looking for23 criteria
The trial’s own eligibility text, word for word from the registry. Only the trial site can say who takes part.
Inclusion
- +Adults with chronic pain. Age greater than or equal to 18 years on the day of enrolmentEnrolmentThe number of participants a study plans to include, or has included.Read more →.
- +Subjects are currently taking a daily opioid pain medication and planning to taper the dose.
- +Participants complete at least one voluntary opioid dose reduction in the twelve-week study period.
- +Glomerular filtration rate (GFR) \> 50 mL/min
- +Capable of providing informed consentInformed consentThe process of being told what taking part involves, then choosing freely.Read more →
Exclusion
- −Allergy to probenecid or related drugs
- −History of uric acid renal calculi, if known to be urate calculi. If unknown type, then any history of renal calculi.
- −Known G6PD deficiency
- −Active gout in any joint
- −Current use of drugs whose exposure may be prolonged, or risk of toxicity increased when used in combination with probenecid:
- −Penicillins, specifically ampicillin, penicillin G sodium, and piperacillin
- −Carbapenems, specifically doripenem and meropenem
- −Lorazepam, midazolam, nitrazepam
- −Oseltamivir
- −Methotrexate
- −Mycophenolate
- −Current use of drugs which may mask symptoms of withdrawal:
- −a. Clonidine, lofexidine, tizanidine
- −Current use of drugs which may diminish the effect of probenecid:
- −a. High dose salicylates including greater than 325 mg PO daily of acetylsalicylic acid (ASA)
- −Any major comorbid medical condition which might impair follow-upFollow-upContinued check-ins after the treatment part is finished.Read more → or result in a safety risk to the participant
- −Participation in another clinical trialInterventional studyA study where participants are given something to see what happens.Read more → investigating a drug, medical device, or a medical procedure during the 30 days prior to enrolmentEnrolmentThe number of participants a study plans to include, or has included.Read more →.
- −Pregnancy or breastfeeding
In plain language
Assembled directly from this trial’s registry record. Every sentence traces to a field below — nothing here is generated or interpreted.
What this study is
This study is testing a treatment for a condition.
Phase 2Phase 2A middle-stage study looking at what a treatment does and watching for side effects.Read more → — a middle-stage study in a few hundred people at most, looking at what the treatment does and watching for side effectsSide effectAn unwanted effect thought to be caused by the treatment itself.Read more →.
From the trial registry
Built from these fields:
- designModule.designInfo.primaryPurpose
- designModule.phases
Who receives what
There are 3 groups in this study.
Groups A and B, the comparison group, receive Probenecid.
Registry label: A: Probenecid 500 mg PO BID · B: Probenecid 1000 mg PO BID
Group C, the placeboPlaceboA dummy treatment with no active medicine, used for comparison.Read more → group, receives Probenecid.
Registry label: C: Placebo PO BID
From the trial registry
Built from these fields:
- armsInterventionsModule.armGroups[].label
- armsInterventionsModule.armGroups[].type
- armsInterventionsModule.armGroups[].interventionNames
How the study is run
Which group you would be placed in is decided by chance, like a coin flip — not by you and not by your doctor.
You, the study team, and the people analysing the results would all be kept unaware of which group you are in until the study ends.
From the trial registry
Built from these fields:
- designModule.designInfo.allocation
- designModule.designInfo.maskingInfo.masking
Is there a placebo?
One group receives a placeboPlaceboA dummy treatment with no active medicine, used for comparison.Read more → — a dummy treatment with no active medicine in it.
One group receives an existing treatment, so the two can be compared.
From the trial registry
Built from these fields:
- armsInterventionsModule.armGroups[].type
- armsInterventionsModule.armGroups[].interventionNames
Who the study is looking for
The study lists an age range of 18 years to 80 years.
The study is open to people of any sex.
The study does not accept healthy volunteersHealthy volunteerSomeone without the condition being studied who takes part anyway.Read more →.
These are the criteria the study lists. Only the trial siteTrial siteA hospital or clinic where a study is actually run.Read more → can decide whether someone can take part.
From the trial registry
Built from these fields:
- eligibilityModule.minimumAge
- eligibilityModule.maximumAge
- eligibilityModule.sex
- eligibilityModule.healthyVolunteers
How big and how long
The study aims to enrol about 40 people.
The study is currently expected to finish around December 2026.
The main measurement is taken over: 12 weeks.
From the trial registry
Built from these fields:
- designModule.enrollmentInfo.count
- statusModule.completionDateStruct.date
- outcomesModule.primaryOutcomes[].timeFrame
What the study measures
To evaluate tolerability of oral probenecid in patients undergoing voluntary opioid tapering — measured over 12 weeks.
To evaluate acceptability of oral probenecid in patients undergoing voluntary opioid tapering — measured over 12 weeks.
To evaluate safety of oral probenecid in patients undergoing voluntary — measured over 12 weeks.
From the trial registry
Built from these fields:
- outcomesModule.primaryOutcomes[].measure
- outcomesModule.primaryOutcomes[].timeFrame
Source: NCT04939623 on ClinicalTrials.gov. The full registry text is further down this page — this summary never replaces it.
Not medical advice. What do these terms mean?
What is being tested — in plain terms
About ProbenecidDrug
The Investigators aim to recruit 40 participants who will be followed for 12 weeks in duration. Participants will be randomized in a 2:2:1 ratio to one of probenecid 500 mg, 1000 mg, or placebo PO BID for 12 weeks. Justification for use of a non-active placebo comparator includes the fact that this trial is meant to identify tolerability and safety of probenecid in a population of patients living with chronic pain, this will be best measured by comparing to a non-active placebo.
From the trial registry — its own words, unedited.
What a drug is here: A medicine — a chemical or small-molecule treatment — given as the thing being studied.
Read the full explanation → · in clinical review
Common questions
Answered from this trial’s registry record. Where the record doesn’t say, these answers say so rather than filling the gap.
Am I eligible for this trial?
Only the trial siteTrial siteA hospital or clinic where a study is actually run.Read more → can decide whether someone can take part. Concord cannot make that determination, and neither can any tool that has not examined you.
What the study lists: an age range of 18 years to 80 years.
The full inclusionInclusion criteriaThe things you must have or be for a study to consider you.Read more → and exclusion criteriaExclusion criteriaThe things that would prevent someone from taking part.Read more → are published on this page, exactly as the study team wrote them.
The useful next step is to bring this trial to your doctor. Answering a few questions first gives them something concrete to review.
From the trial registry
- eligibilityModule.minimumAge
- eligibilityModule.maximumAge
- eligibilityModule.eligibilityCriteria
Is there a placebo?
Yes. This study includes a placeboPlaceboA dummy treatment with no active medicine, used for comparison.Read more → group — a dummy treatment with no active medicine in it.
One group receives an existing treatment so the two can be compared.
From the trial registry
- armsInterventionsModule.armGroups[].type
Would I know which treatment I am getting?
You, the study team, and the people analysing the results would all be kept unaware of which group you are in until the study ends.
Which group you would be placed in is decided by chance, like a coin flip — not by you and not by your doctor.
From the trial registry
- designModule.designInfo.maskingInfo.masking
- designModule.designInfo.allocation
Who can join?
The study lists an age range of 18 years to 80 years.
It is open to people of any sex.
It does not accept healthy volunteersHealthy volunteerSomeone without the condition being studied who takes part anyway.Read more →.
Only the trial siteTrial siteA hospital or clinic where a study is actually run.Read more → can confirm whether a particular person can take part.
From the trial registry
- eligibilityModule.minimumAge
- eligibilityModule.maximumAge
- eligibilityModule.sex
- eligibilityModule.healthyVolunteers
How long would this take?
The study's main measurement is taken over: 12 weeks.
The study as a whole is currently expected to finish around 2026-12-31.
How long any one person takes part can differ from the study length. The study team can tell you what the schedule looks like in practice.
From the trial registry
- outcomesModule.primaryOutcomes[].timeFrame
- statusModule.completionDateStruct.date
How many people are taking part?
The study aims to enrol about 40 people.
From the trial registry
- designModule.enrollmentInfo.count
Where is this happening?
This study lists one location: Calgary, Alberta, Canada.
Sites can open and close during a study, so confirm with the team before travelling.
From the trial registry
- trial_locations
About This Trial
The proposed clinical trial will address the problem of opioid withdrawal. Opioids are essential for pain-relief in the short term, but their continued use is associated with a host of adverse effects. People living with chronic pain who were initiated on opioid therapy now find themselves with a major life-changing problem - dependence on opioid medications. Opioid withdrawal symptoms are a key barrier to decreasing or stopping their opioid medication. Currently, there are few medications that ameliorate the symptoms of opioid withdrawal. This problem is a major part of the opioid crisis in Canada, and impacts people across all demographics and socioeconomic status. A misconception is that only individuals with opioid use disorder are susceptible to opioid withdrawal; on the contrary, appropriate use of prescription opioids to manage pain can lead to significant symptoms of opioid withdrawal when it is reduced or stopped. Patients in Alberta who are at risk for opioid withdrawal, either from prescribed use or misuse will be primarily impacted by this trial. The investigators have recently explored the underlying causes of opioid withdrawal and identified an important target in the spinal cord that is responsible for producing withdrawal symptoms in rats and mice. The target, a protein called pannexin-1 (Panx1), is located throughout the body, specifically in the brain and spinal cord. Using sophisticated biochemical, genetic, and pharmacological techniques, the investigators demonstrated how Panx1 on immune cells is implicated in the production of opioid withdrawal symptoms after cessation of fentanyl and morphine in opioid dependent rodents. The investigators then attenuated these symptoms of withdrawal using probenecid, a drug which inherently blocks Panx1 activity. Because probenecid is a safe and clinically available drug, the findings could be immediately translated into clinical therapy to support people who are struggling with the symptoms of opioid withdrawal and provide clinicians with a safe and effective option for caring for this population.
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See if this trial could fit youThis page is for informational purposes only and does not constitute medical advice. Clinical trial eligibility can only be determined by the trial site after proper screening. Trial information is sourced from ClinicalTrials.gov and may not reflect the most current status. Always consult your healthcare provider before making decisions about clinical trial participation.