Intravenous magnesium sulfate vs. morphine sulfate in relieving renal colic: A randomized clinical trial

Am J Emerg Med. 2021 Aug;46:188-192. doi: 10.1016/j.ajem.2020.07.035. Epub 2020 Jul 21.


Objective: Renal colic emerging from renal stone is virtually the most severe pain which is experienced. Intravenous infusion of morphine sulfate is known as a usual treatment for the disease. This study was designed to compare the efficacy of magnesium sulfate vs morphine sulfate in renal colic relief as for analgesic effect as well as lack of morphine sulfate side effects when using magnesium sulfate.

Methods: We conducted a double-blind randomized clinical trial in renal colic patients who had referred to the emergency department of Shahid Sadoughi Hospital in Yazd, Iran. A total of 80 eligible patients were selected and randomly assigned into two groups; patients in the case group received 50 mg/kg intravenous magnesium sulfate, and those in the control group 0.1 mg/kg intravenous morphine. The primary outcome was the pain score measured on a numerical rating scale at 0, 10 and 20 minutes after infusion. Data were analyzed using SPSS16.

Results: The two groups were similar in terms of demographic features and pain intensity at the time of referral (P <.0001). Ten minutes after drug administration, the pain mean score in the morphine group leveled at 4.88, and in the magnesium group 5.70, which proved to be greater in the morphine group (P- = 0.06). However, the pain mean score turned out to be 3.65 in the morphine group and 3.20 in the magnesium group thus significantly indifferent (P = .48).

Conclusions: In this study, we concluded that administration of intravenous 50 mg/kg magnesium sulfate could be as effective as morphine in reducing renal colic without any further complications.

Keywords: Magnesium sulfate; Morphine; Pain management; Randomized controlled trial; Renal colic.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Analgesics / administration & dosage
  • Analgesics / therapeutic use*
  • Analgesics, Opioid / administration & dosage
  • Analgesics, Opioid / therapeutic use*
  • Female
  • Humans
  • Infusions, Intravenous
  • Iran
  • Magnesium Sulfate / administration & dosage
  • Magnesium Sulfate / therapeutic use*
  • Male
  • Middle Aged
  • Morphine / administration & dosage
  • Morphine / therapeutic use*
  • Pain Management / methods*
  • Pain Measurement
  • Renal Colic / drug therapy*


  • Analgesics
  • Analgesics, Opioid
  • Magnesium Sulfate
  • Morphine