Effect of vitamin C on morphine use after laparoscopic cholecystectomy: a randomized controlled trial

Can J Anaesth. 2012 Jun;59(6):538-43. doi: 10.1007/s12630-012-9692-x. Epub 2012 Mar 9.


Purpose: We designed a randomized double-blind placebo-controlled trial to assess the role of a single prophylactic dose of vitamin C (2 g) po in reducing the consumption of opioids postoperatively in patients undergoing laparoscopic cholecystectomy.

Methods: Eighty adult patients were allocated to receive 2 g vitamin C po or placebo approximately one hour prior to induction of anesthesia. Following laparoscopic cholecystectomy, patients received morphine patient-controlled analgesia for 24 hr. The following data were assessed postoperatively in the postanesthesia care unit at two, four, six, 12, and 24 hr: morphine consumption, verbal numerical rating scale scores for incisional pain and nausea/vomiting, and pruritus and sedation scores. The primary outcome measure was 24-hr morphine consumption. Patient satisfaction was assessed before hospital discharge.

Results: Morphine consumption was significantly lower in the vitamin C group vs the placebo group [16.2 (10.7) and 22.8 (13.8) mg, respectively; difference = 6.6 mg; 95% confidence interval, 1.1 to 12.1 mg; P = 0.02]. There was no difference in pain scores or side effects between the two groups. Satisfaction scores were similar in both groups.

Conclusion: Our study showed that supplementation with vitamin C (2 g) po decreased morphine consumption in the postoperative period in patients undergoing laparoscopic cholecystectomy.

Trial registration: ClinicalTrials.gov NCT01322061.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analgesia, Patient-Controlled / methods
  • Analgesics, Opioid / administration & dosage
  • Ascorbic Acid / administration & dosage
  • Ascorbic Acid / therapeutic use*
  • Cholecystectomy, Laparoscopic / methods*
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Morphine / administration & dosage*
  • Pain, Postoperative / prevention & control*
  • Patient Satisfaction
  • Preoperative Care
  • Time Factors
  • Treatment Outcome
  • Vitamins / administration & dosage
  • Vitamins / therapeutic use


  • Analgesics, Opioid
  • Vitamins
  • Morphine
  • Ascorbic Acid

Associated data

  • ClinicalTrials.gov/NCT01322061