Effect of Vitamin C on Pain Reduction After an Emergency Department Visit (Vicamed)

February 27, 2026 updated by: Raoul Daoust, Centre Integre Universitaire de Sante et Services Sociaux du Nord de l'ile de Montreal

Vitamin C for Acute Musculoskeletal Pain in Emergency Department Patients: A Triple-Blind Randomized Control Trial (VICAMED)

Musculoskeletal (MSK) injuries such as sprains, strains, bruises, and fractures are among the most common reasons people visit the emergency department. These injuries often cause significant pain in the first few days, making it difficult to move, work, or sleep. Usual pain medications like ibuprofen or acetaminophen can help, but they are not safe or effective for everyone. Some people cannot take them because of heart, kidney, stomach, or liver problems. Others still experience strong pain despite treatment. Because of these limits, some patients receive opioids, which can cause side effects and carry a risk of dependence. Safer and more accessible options are needed.

Vitamin C is widely known for supporting the immune system, but research suggests it may also help reduce pain and inflammation. Studies in surgical patients have shown that vitamin C can lower pain levels, reduce the need for opioids, and support healing. These effects may be linked to its antioxidant properties and its role in tissue repair. However, no study has tested whether vitamin C can help people with recent MSK injuries treated in the emergency department.

The VICAMED study aims to answer this question. Adults arriving with an MSK injury that occurred within the past 48 hours can participate if they have at least moderate pain. Participants are randomly assigned to receive either vitamin C or a placebo. The first dose is given in the emergency department, followed by twice daily capsules for three days. Pain is measured using a simple 0-100 scale, recorded in an electronic or paper diary. A follow-up on day six helps the research team understand each participant's recovery, medication use, and overall experience.

Vitamin C is inexpensive, widely available, and very safe at the doses used in this study. If it proves effective, it could offer a simple, low risk option to help patients manage pain after an MSK injury and reduce the need for opioids in emergency care.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background:

Acute musculoskeletal (MSK) injuries are a major cause of emergency department (ED) visits and frequently result in moderate to severe pain during the first days following presentation. First-line analgesics such as NSAIDs and acetaminophen have important contraindications and safety limitations, particularly in older adults and patients with comorbidities, underscoring the need for safe, accessible, opioid-sparing alternatives. Preclinical studies and postoperative trials suggest that vitamin C (ascorbic acid) may provide analgesic and anti-inflammatory effects through reduction of oxidative stress, protection of neural tissues, and enhanced collagen synthesis. Meta-analyses have reported reductions in postoperative opioid consumption, pain intensity, and inflammatory markers. However, no randomized controlled trial has evaluated vitamin C for acute traumatic MSK pain in the ED.

Objective:

The primary objective is to determine whether a single 900 mg oral dose of vitamin C reduces pain intensity one hour after administration compared with placebo in adults presenting with acute MSK injuries. The main secondary objective is to assess whether 900 mg of vitamin C taken twice daily for three days reduces the time-weighted sum of pain-intensity difference (SPID) over 72 hours.

Methods:

The VICAMED study is a multicentre, triple-blind, randomized, placebo-controlled trial conducted in three university-affiliated EDs in Canada. Eligible participants are adults aged ≥18 years with MSK pain ≤48 hours, triaged to ambulatory care, and reporting pain >3/10. Exclusion criteria include recent vitamin C use, active cancer, recent analgesic intake, chronic pain treatment, and contraindications such as oxalate nephropathy or interactions with cyclosporine or warfarin. Participants receive an initial 900 mg dose of vitamin C or placebo in the ED, followed by twice-daily dosing for three days. Pain intensity is measured using validated 0-100 visual analog scales through electronic or paper diaries. A structured day-six follow-up captures missing data, analgesic use, adverse events, and health-related quality of life (EQ-5D-5L). The primary analysis uses ANCOVA adjusting for site and fracture status. Secondary analyses evaluate SPID72, analgesic consumption, time to significant pain relief, time to pain-free, proportion of days with adequate relief, adverse events, and healthcare utilization.

Based on a minimal clinically important difference of 13 points on a 0-100 pain scale and prior variance estimates, 204 participants are required for the primary outcome. The sample size for SPID72 will be finalized using pilot study data currently being analyzed. The study is powered to detect clinically meaningful differences in both immediate and short-term pain trajectories.

Expected Results:

If vitamin C demonstrates analgesic efficacy in acute MSK injuries, it could represent a safe, inexpensive, widely accessible, and opioid-sparing therapeutic option for ED patients, including those unable to use NSAIDs or acetaminophen. Given its favourable safety profile and over-the-counter availability, vitamin C has strong potential for rapid clinical integration. The research team's established collaborations within national emergency medicine networks will support broad dissemination and facilitate implementation across Canadian EDs.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
204

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Canada
    • Ontario
      • Ottawa, Ontario, Canada, K1Y 1J8
        • Not yet recruiting
        • The Ottawa Hospital - General and Civic Campus
        • Contact:
          • Gabriel Sandino-Gold, BSc
          • Phone Number: 17709 613-798-5555
          • Email: gsandino@ohri.ca
    • Quebec
      • Lévis, Quebec, Canada, G6V 3Z1
        • Not yet recruiting
        • Hotel-Dieu De Levis
        • Contact:
        • Principal Investigator:
          • Patrick Archambault, MD MSc
      • Montreal, Quebec, Canada, H4J 1C5
      • Québec, Quebec, Canada

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Age ≥ 18 years old
  2. Presenting to the ED with acute MSK pain of ≤ 48 hours duration at triage
  3. Verbal numerical rating scale pain intensity at triage of ≥ 4 on a 0-10 scale
  4. Triaged to the ambulatory section of the ED
  5. Able to communicate in French or English

Exclusion Criteria:

  1. Usage of Vit C supplements in the last week
  2. Active cancer
  3. Treated with opioids for any pain within 24 hours prior to recruitment
  4. Treatment for chronic pain
  5. Unable to fill out a pain intensity diary or unavailable for follow-up
  6. Allergy to milk (lactose in the placebo) or Vit C
  7. Treated with cyclosporine or warfarin
  8. Pre-existing oxalate nephropathy, liver cirrhosis or hemochromatosis
  9. Hospitalized after clinician evaluation

Study Plan

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

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Vitamin C
900 mg vitamin C taken orally twice a day
Dietary supplement: Vitamin C
900 mg vitamin C taken orally twice a day (one in the morning and one in the evening) for a 3-day period after ED discharge for the treatment arm.
Placebo Comparator: Placebo
Placebo taken orally twice a day
Other: Placebo
Placebo taken orally twice a day (one in the morning and one in the evening) for a 3-day period after ED discharge for the treatment arm.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Time-weighted sum of the pain-intensity difference (SPID)
Time Frame: Three days
The primary outcome is the time-weighted sum of the pain-intensity difference (SPID) over the three-day treatment period on a 0-100 visual analog scale (VAS), where 0 is no pain and 100 the worst pain imaginable. The SPID accounts for both the magnitude of the pain change and its duration, producing a single value that reflects the patient's overall experience.
Three days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Consumption of as-needed pain medication
Time Frame: Three days
Participants will be asked the name and the total amount of pain medication taken during the three-day follow-up.
Three days
Percentage of days with adequate relief
Time Frame: Six days
To assess the proportion of days with adequate pain control, participants will answer a daily yes/no question regarding whether their pain was adequately relieved.
Six days
New analgesic prescriptions
Time Frame: Three days
Numbered and of new pain medication prescription received during follow-up, even opioids.
Three days
Adverse events
Time Frame: Three days
We will document during the day-six questionnaire if any of the following adverse events were experienced during the three-day period: nausea, vomiting, constipation, dizziness, drowsiness, sweating, weakness, or other adverse events.
Three days
Quantity of Healthcare visits
Time Frame: Six days
Participants will be asked about the number of all unscheduled or scheduled healthcare visits related to their initial pain condition during the day-6 questionnaire.
Six days
Difference in pain intensity
Time Frame: Three days
The main secondary outcome is the difference in pain intensity, also measured on a 0-100 visual analog scale (VAS), where 0 is no pain and 100 the worst pain imaginable, between groups one hour after taking the first study drug in the ED.
Three days
Time for significant pain relief
Time Frame: Six days
Time for significant pain relief, reported in hours, is define in a 50% reduction in pain intensity.
Six days
Time to pain-free
Time Frame: Six days
Time, reported in hours, when pain reach 0 on a 0-100 visual analog scale (VAS), where 0 is no pain and 100 the worst pain imaginable
Six days
Quality of life improvement at six days
Time Frame: Six days

Health-related quality of life will be assessed using the validated EQ-5D-5L questionnaire.

EuroQol - five dimensions - 5 levels.

It assesses five dimensions (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) across 5 levels of severity-from no problems to extreme problems-providing a 5-digit health state profile used in clinical research and economic evaluations.

Common Interpretation:

11111: Perfect health (Index 1.0). 55555: Worst health (lowest possible index).
Six days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Centre Integre Universitaire de Sante et Services Sociaux du Nord de l'ile de Montreal

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
The Ottawa Hospital
Hopital de l'Enfant-Jesus

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Raoul Daoust, MD MSc, Université de Montréal

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 28, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 5, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 12, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2024-2829

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

IPD could be shared upon request, upon approval by our institution.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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