Study Rationale Literature suggests that the administration of vitamin C has an effect in
reducing pain and opioid consumption in the context of immediate postoperative acute
pain. However, the investigators could not find evidence on the effectiveness of vitamin
C administration after an ED visit in the context of acute pain, notably in trauma
injuries like fractures, bruises, sprains, strains, etc. Previous studies have only
evaluated pain relief and opioid use for the immediate postoperative period of 24 to 72
hours. Therefore, the investigators propose to evaluate the efficacy of a 14-day regiment
of vitamin C given to ED patients discharged with an opioid prescription for acute
musculoskeletal (MSK) pain on total opioid consumption after two weeks. The two-week
period was chosen because it defines the usual acute pain time frame, during which need
for analgesics including opioids is essentially resolved in most patients (88% of our
previous study cohort). Furthermore, since vitamin C is also associated with less
post-herpetic neuralgia and complex regional pain syndromes (CRPS), the investigators
also propose to evaluate its impact on the incidence of chronic pain and CRPS at 3
months.
Study Objectives The primary aim is to compare the difference in the total morphine 5 mg
equivalent pills consumed after a two-week follow-up between patients receiving vitamin C
versus patients receiving a placebo during these two weeks.
The secondary aims are to compare the following between patients receiving vitamin C vs
patients receiving a placebo: pain intensity trajectories, average pain relief during the
two-week, side effects, total morphine 5 mg equivalent pills consumed after a two-week
follow-up for each type of MSK pain (fracture, contusions, cervical pain, lower back
pain, MSK pain at other sites), incidence of chronic pain (including CRPS) at 3 months
globally and for each type of MSK pain, incidence of CRPS for limb fractures, and for a
wrist fracture in particular at 3 months, and prevalence of opioid use at 3 months.
Study Design The investigators will conduct a multi-center, double-blind, randomized,
placebo-controlled trial performed in two tertiary trauma care university-affiliated
hospitals located in Montreal and in Quebec City (Quebec, Canada) with an annual census
of 60,000 and 67,000 visits, respectively.
Participants and recruitment Consecutive patients (from 8 to 20h every day) diagnosed
with an acute musculoskeletal pain complaint ongoing for less than two weeks and
discharged from the ED with an opioid prescription will be approached by the treating
clinician to participate in the study and obtain their verbal consent to be seen by a
research assistant. The decision to prescribe opioids will be at the discretion of the
treating physician, but included patients will receive a standardized prescription of 20
pills of morphine 5 mg based on our previous work. The research assistant will then
verify the patient's inclusion and exclusion criteria, explain the research protocol, and
obtain informed written consent. Patients will be assessed via a two-week electronic (or
paper) diary and contacted 3 months after ED discharge.
Randomization method and blinding Eligible patients will be block randomized at the
initial visit (via 1:1 ratio) to either 1 000 mg vitamin C taken orally twice a day or
matching placebo, using a centralized randomisation web system. Allocation concealment
will be in place to ensure that the investigator and the individual enrolling the subject
into the study have no prior knowledge of group assignment. Since fractures are
associated with more opioid consumption, randomization will be a stratified by fracture
or not and centre. According to the centralized web system, an independent pharmacist
will dispense pre-packed numbered bottles of either vitamin C or placebo capsules for
each patient. Both will be dispensed an identical capsules and the pharmacist will be
unaware of the trial-group assignments. Each participant will be assigned a number and
received the capsules in the corresponding pre-packed bottle. Group allocation will be
disclosed only after final analysis or at the request of the patient's treating
clinician.
Study drug Vitamin C (ascorbic acid) is a vital nutrient; it helps form and maintain
bones, skin, and blood vessels and has antioxidant properties. It is not produced by the
human body but occurs naturally in fruits and vegetables and other foods. It is also
available as supplement over the counter in pharmacies, supermarkets, and health
supplements stores and online. For adults, the recommended daily amount of vitamin C is
65 to 90 milligrams (mg) a day (Recommended Dietary Allowances by the Government of
Canada).