Magnesium and Cramping

Hysteroscopy (an exam to look inside the uterus) is one of the most frequently performed procedures for patients with cervical or uterine disorders. It is the gold standard for evaluating various intrauterine problems, pre-menopausal and post-menopausal abnormal uterine bleeding, as well as being a vital examination modality for infertility work-up. Although hysteroscopy is a minimally invasive procedure, it is still known to be a painful experience that requires effective analgesia (meaning pain reduction) to achieve maximum patient comfort and cooperation. Historically, opioids, particularly fentanyl, have held precedence as the primary agents for providing analgesia following surgery of this type. However, despite their efficacy, these agents come with notable drawbacks, including the potential for serious side effects such as respiratory depression, addiction, and postoperative nausea and vomiting.

Both magnesium and ketamine are routinely used to reduce pain following this procedure. Both drugs work on the N-methyl-D-aspartate (NMDA) receptor in the brain to reduce pain, and magnesium has an additional effect in that it can relax smooth muscles. Magnesium has been used successfully to reduce the pain associated with menstrual cramps, which is similar to the pain patients experience after hysteroscopy.

A recent study demonstrated the benefits of adding intravenous magnesium with routine anesthesia during hysteroscopy, revealing a significant decrease in postoperative pain and rescue analgesics. However, this study did not compare the effects of magnesium to ketamine, nor did they characterize the nature of the patients' pain. It is unclear if the pain reduction with magnesium comes from its effect on the NMDA receptor or from it's cramp-reduction effect. We seek to establish whether administering IV magnesium, compared to ketamine, can specifically mitigate uterine cramping pain and total opioid consumption in hopes of finding additional safe and effective pain modalities for patients.

This is a prospective, randomized trial enrolling participants undergoing an elective hysteroscopy or Dilation and Curettage (D&C) at Corewell Health William Beaumont University Hospital in Royal Oak. Participants will be randomized to 1 of 3 treatments: Intravenous (IV) Magnesium, IV Push Ketamine, or Placebo. Opioid consumption is recorded via the electronic medical record (EMR), while overall pain and cramping pain will be captured post-procedure in the hospital and 24 hours later via a phone call.