Testing Vitamin C against a placebo for acute pain
Official title: Impact of Vitamin C on opioïd Consumption After an Emergency Department Visit for Acute Musculoskeletal Pain
Impact of Vitamin C on the Reduction of Opioid Consumption After an Emergency Department Visit for Acute Musculoskeletal Pain: A Double-Blind Randomized Control Trial Protocol
- 2 groups
- One site, in Montreal
- Recruiting
Interventions
- Other intervention
Vitamin C
1000 mg vitamin C taken orally twice a day (one in the morning and one in the evening) for a 14-day period after ED discharge for the treatment arm
- Other intervention
Placebo
Placebo taken orally twice a day (one in the morning and one in the evening) for a 14-day period after ED discharge for the treatment arm
Canadian Sites (1)
1 of 1 recruiting
- Recruiting
Hôpital du Sacré-Coeur de Montréal
Montreal, Quebec
Eligibility Criteria
See who this study is looking for13 criteria
The trial’s own eligibility text, word for word from the registry. Only the trial site can say who takes part.
Inclusion
- +Aged 18 and over;
- +Treated in ED for acute musculoskeletal pain present for less than 2 weeks;
- +Discharged with an opioid prescription;
- +Speaks French or English.
Exclusion
- −Any allergy, intolerance or sensitivity to milk (lactose) or morphine
- −Opioid use 1 month prior to the ED visit;
- −Already taking vitamin C supplement;
- −Active cancer;
- −Treated for chronic pain;
- −Treated for opioid use disorder;
- −Unable to fill out diary or unavailable for follow-upFollow-upContinued check-ins after the treatment part is finished.Read more →;
- −Treated with cyclosporin or coumadin
- −Pregnant or lactating (dosage \> 1,800 mg not recommended. For women of child-bearing age and sexually active in the past 3 months, a urine pregnancy test will be performed.)
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 investigating how something functions in the body, rather than testing a treatment directly.
This study is not organised into the usual phase numbers — that is common for device, behavioural, and diagnostic research.
From the trial registry
Built from these fields:
- designModule.designInfo.primaryPurpose
- designModule.phases
Who receives what
There are 2 groups in this study.
Group A receives Vitamin C.
Registry label: A: Vitamin C
Group B, the placeboPlaceboA dummy treatment with no active medicine, used for comparison.Read more → group, receives Placebo.
Registry label: B: Placebo
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.
From the trial registry
Built from these fields:
- armsInterventionsModule.armGroups[].type
- armsInterventionsModule.armGroups[].interventionNames
Who the study is looking for
The study lists a minimum age of 18 years, with no upper limit given.
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.sex
- eligibilityModule.healthyVolunteers
How big and how long
The study aims to enrol about 464 people.
The study is currently expected to finish around December 2026.
The main measurement is taken over: 14 days.
From the trial registry
Built from these fields:
- designModule.enrollmentInfo.count
- statusModule.completionDateStruct.date
- outcomesModule.primaryOutcomes[].timeFrame
What the study measures
Difference in the total morphine 5 mg equivalent pills consumed — measured over 14 days.
From the trial registry
Built from these fields:
- outcomesModule.primaryOutcomes[].measure
- outcomesModule.primaryOutcomes[].timeFrame
Source: NCT05555576 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 Vitamin CDietary supplement
1000 mg vitamin C taken orally twice a day (one in the morning and one in the evening) for a 14-day period after ED discharge for the treatment arm
From the trial registry — its own words, unedited.
What a dietary supplement is here: A vitamin, mineral, or other supplement being studied.
Read the full explanation → · in clinical review
About PlaceboOther
Placebo taken orally twice a day (one in the morning and one in the evening) for a 14-day period after ED discharge for the treatment arm
From the trial registry — its own words, unedited.
What a other is here: An intervention the registry did not place in another category.
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: a minimum age of 18 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.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.
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 a minimum age of 18 years, with no upper limit given.
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.sex
- eligibilityModule.healthyVolunteers
How long would this take?
The study's main measurement is taken over: 14 days.
The study as a whole is currently expected to finish around 2026-12.
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 464 people.
From the trial registry
- designModule.enrollmentInfo.count
Where is this happening?
This study lists one location: Montreal, Quebec, 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
Recent evidence has shown that vitamin C has some analgesic properties and can therefore reduce opioids used during healing. Vitamin C analgesic effect has been explored mostly during the short-term postoperative context or in disease specific chronic pain prevention but not after acute musculoskeletal injuries, which are often seen in the emergency department (ED). The study's primary aim is to compare the total morphine 5 mg equivalent pills consumed during a two-week follow-up between patients receiving vitamin C or a placebo after ED discharge for an acute musculoskeletal pain complaint. The investigators will conduct a double-blind randomized placebo-controlled trial with 464 participants distributed in two arms, one group receiving 1 000 mg of vitamin C twice a day for 14 days and another one receiving a placebo. Participants will be ≥18 years of age, treated in ED for acute musculoskeletal pain present for less than 2 weeks, and discharged with an opioid prescription for home pain management. Total morphine 5 mg equivalent pills consumed during the two-week follow-up will be assessed via an electronic (or paper) diary. In addition, patients will report their daily pain intensity, pain relief, side effects, and other types of pain medication or other non-pharmacological approach (ice, heat, immobilization, etc.) used. Three months after the injury, participants will also be contacted to evaluate chronic pain development. The investigators hypothesized that vitamin C, compared to a placebo, will reduce opioid consumption during a 14-day follow-up for ED discharged patients treated for acute pain.
Think this trial might be right for you?
Complete a quick intake form and we will match you with this and other relevant trials based on your medical profile.
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.