Physicians, health care providers, and medical staff caring for patients who use cannabis should be familiar with the effects of the drug on gut motility and thus nuclear medicine imaging, a recent report advises.
“Understanding the effects of cannabis and weight loss drugs on gut motility – that is the movement of food throughout the body – is essential for nuclear medicine providers,” said Rutger Gunther, MD, in a March 5 news release from the Society of Nuclear Medicine and Molecular Imaging.
Gunther, a radiologist at UT Health San Antonio, and colleagues penned an article published in the March issue of the Journal of Nuclear Medicine Technology titled, “Got the Munchies for an Egg Sandwich? The Effects of Cannabis on Bowel Motility and Beyond.”
In the article, the authors suggested that with the expanding legalization of cannabis and its increased use, physicians need to be more attuned to its side effects specifically for performing gastric emptying scans (GES).
“Gastric emptying scintigraphy remains the primary imaging modality for evaluating symptoms of gastroparesis such as abdominal pain, bloating, nausea, loss of appetite, and more,” the group noted.
As of 2023, 38 states allow the medical use of cannabis, 23 states allow the recreational use of cannabis, and nine states allow low delta-9-tetrahydrocannabinol (THC)/high cannabidiol (CBD) ratio cannabis. Although gastroenterology literature has described the effect of cannabinoids on the gut, there is a lack of research in the field of nuclear medicine, the authors wrote.
Historically, cannabis has been associated with decreased gastrointestinal motility, yet paradoxically, recent research strongly suggests the drug may improve the normal spontaneous movement of muscles in the stomach (gastroparesis), according to the authors.
For instance, two double-blind, experimental studies conducted in 1990 and 2006 validated delayed gastric emptying using GES in healthy volunteers after oral THC intake. One study including 13 healthy volunteers demonstrated statistically significant delays in gastric emptying at two hours, with a 40% increase in average percentage retention.
Yet the authors noted that a recent large National Institutes of Health-sponsored trial found that 81% of cannabis users perceived benefits in their gastroparesis symptoms, the authors wrote. The study investigators reported that cannabis users represented a minority of all gastroparesis patients (12% of 506 patients) and had higher baseline scores for nausea, vomiting, and upper abdominal pain.
“The seemingly contradictory cannabinoid effects that improve gastroparetic symptoms but likely delay gastric emptying have yet to be elucidated,” the authors noted.
Nonetheless, the authors advised that any significant delays in gastric emptying would likely be limited to instances of very recent intake (less than 12 hours). Thus, social history should be reviewed for all forms of cannabinoids (medical or recreational marijuana, dronabinol-THC, and synthetic cannabinoids such as K2 or Spice). To avoid false-positive results, they recommended patients avoid cannabinoid intake for at least 72 hours before GES, although no cannabis after midnight would likely suffice, they wrote.
“Cannabinoids should be added to the list of medications that may affect gastric emptying per the Society of Nuclear Medicine and Molecular Imaging procedure standards for GES,” the authors concluded.
The full article is available here.
