Patients with renal colic are often in severe pain, requiring rapid analgesia. NSAIDs are the recommended analgesic, however opioid analgesics are often needed. In this study the authors “hypothesized that in ED patients with acute renal colic, more effective analgesia would occur when either IV lidocaine or MgSO4 were added to IM diclofenac.”
The Study
Toumia M et al. Magnesium Sulfate Versus Lidocaine as an Adjunct for Renal Colic in the Emergency Department: A Randomised, Double-Blind Controlled Trial. Ann Emerg Med 2024 Dec;84(6):670-677. PMID: 39033450
Bottom Line
I think this is a positive study…. perhaps. It demonstrated that rescue analgesia was needed less often in the MgSO4 group and that patients achieved a more rapid decrease in pain with MgSO4, there was no difference between the 3 groups in terms of pre-determined clinical importance (pain < 1.3/10).
All three groups had a high pain score at presentation ( all > 8/10). I will usually give antiinflammatories but may give IV narcotic analgesia simultaneously, if the patient is in significant pain and 8.5/10, as was found in this study, is significant pain.
This study won’t change my practice, as I think a small dose of narcotic analgesia works very effectively and I usually won’t wait too long to acutely reduce the patient’s pain. I may consider using MgSo4, if the patient has allegies to narcotics, or if the pain seems to be refractory to narcotics, although there are also other options, that are probably more effective.
