Effect of Vitamin C on Pain Reduction After an Emergency Department Visit
Emergency department (ED) clinicians often prescribe anti-inflammatory drugs (NSAIDs) to manage acute musculoskeletal (MSK) pain (e.g.: fracture, sprain, back pain). However, even short-term NSAIDs use can have significant gastrointestinal, cardiovascular, MSK and renal adverse effects. For this reason, some patients cannot take or tolerate NSAIDs. Recent evidence has shown that vitamin C has some analgesic and anti-inflammatory properties particularly in postoperative context and prevent specific types of chronic pain. Furthermore, vitamin C is safe and associated with very few adverse events. The primary objective of this study is to determine whether vitamin C can reduce pain intensity during a seven-day period following an ED visit for acute MSK pain.

The investigators propose to compare two groups of patients, one receiving 900 mg of vitamin C to another receiving a placebo, twice a day for seven days. Both groups will consume acetaminophen slow release 650 mg two pills every eight hours regularly. Naproxen 500 mg (NSAID) will be used as a rescue medication if the patient's pain is not relieved. Participants will be ≥18 years of age, treated in ED for acute MSK pain present for less than 48 hours with pain intensity at triage of ≥ 4 on a 0-10 numeric rating scale, and discharged by an ED clinician with an NSAIDs prescription without opioids. The level of pain intensity during a seven-day period will be assessed daily using an electronic or paper diary, as well as pain relief, pain medication consumption, and adverse events. Three months after the injury, participants will also be contacted to assess the presence of chronic pain. The investigators hypothesized that vitamin C will reduce pain intensity and chronic pain development at three months.

This research could provide a safe alternative to patients who are unable to take NSAIDs. It may also contribute to the reduction of the burden associated with chronic pain development.
- EligibilityCriteria: Inclusion Criteria:  Age ≥ 18 years old Treated in the ED for acute MSK pain present ≤ 48 hours at triage (time to presentation for most acute MSK pain in our previous study) Numerical rating scale (NRS) pain intensity at triage of ≥ 4 on a 0-10 scale Discharged with instructions to take an NSAID for pain (need determined by treating clinicians) French or English-speaking  Exclusion Criteria:  Received an opioid prescription at ED discharge Currently using vitamin C supplements Active cancer Currently treated for chronic pain Unable to fill out a diary or unavailable for follow-up Allergy, to milk (lactose in the placebo), vitamin C, acetaminophen or NSAIDs Treated with cyclosporine or warfarin (interaction with vitamin C) Pre-existing oxalate nephropathy, liver cirrhosis or hemochromatosis Pregnant ≥ 20 weeks. - HealthyVolunteers: No - Gender: All - GenderBased: Yes - GenderDescription: Gender is self identified by participants. - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult