Impact of Vitamin C on opioïd Consumption After an Emergency Department Visit for Acute Musculoskeletal Pain

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.