An unpleasant syndrome surfaces as cannabis use grows
Key Takeaways
New cannabis risks are emerging due to the increase in use among your patients.
It may be surprising, but cannabis has biphasic effects based on potency.
Cannabinoid hyperemesis has close ties to cyclic vomiting syndrome, but there are important distinctions between both conditions. Knowing how to distinguish the two is imperative for proper diagnosis and treatment.
We’ve all read the reports and understand that cannabis use is rising among many of our patients, and due to the increased access to the drug, some lesser-known negative effects are coming to light.[]
Although some patients use medical marijuana for its antiemetic properties, more recently, cannabis has garnered attention for its possible connection with nausea and vomiting—two symptoms of a medical condition called cannabinoid hyperemesis syndrome (CHS).
Confronting the paradox
CHS is characterized by “cyclical episodes of nausea and vomiting, accompanied by abdominal pain following prolonged, high-dose cannabis use.”[]
Increased reports of CHS may come as a surprise to physicians whose patients turn to cannabis to relieve nausea and vomiting. The thing is, cannabis has biphasic effects, and the frequency of use and potency of the drug can make the difference between antiemetic and emetic actions—with low doses having an antiemetic effect and high doses producing emesis, according to the authors of a review on CHS pathophysiology.[]
Thangam Venkatesan, MD, a professor of clinical medicine in gastroenterology, hepatology, and nutrition at Ohio State University Wexner Medical Center, agrees that cannabis potency makes all the difference. “High-risk cannabis use really needs to be defined by potency, by frequency, and by mode of inhalation,” she says. These distinctions are crucial when determining the role of cannabis in a patient’s symptoms, she explains.
Signs and symptoms of CHS closely mirror those of cyclic vomiting syndrome (CVS). Consequently, whether CHS is completely separate from CVS isn’t totally clear. According to authors of a review in the Journal of Medical Toxicology, “A diagnostic dilemma arises when CVS patients concurrently use cannabis, as it can be difficult to discern if the true underlying disorder is CHS or CVS that is being symptomatically managed with cannabis.”[]
@docschmidt In honor of 420, let’s learn about Cannabinoid Hyperemesis Syndrome. Believe it or not, sometimes MJ can CAUSE nausea and vomiting! This video is sponsored by Esse Health! #ad ♬ original sound - Doc Schmidt
Dr. Venkatesan refers to CHS as “a subset of cyclical vomiting syndrome,” adding, “whether it’s a separate disorder, I don’t think is clear.” She emphasizes that potency must be considered when evaluating patients who are cannabis users: “Not all cannabis is made equal,” she tells MDLinx. “The problem is that cannabis potency has increased over the last two decades. What has happened, I think, is that [cannabis] is exacerbating or unmasking symptoms in people who are probably predisposed to cyclic vomiting.”
Making the diagnosis
Because of its similarities to CVS, CHS may be difficult to distinguish, especially given its biphasic effects. “A careful social history is needed in all cyclic vomiting patients,” write the review authors in the Journal of Medical Toxicology.
“Cannabis has various therapeutic properties including anti-emesis, appetite stimulation, and analgesia.” They note that “cyclic vomiting patients and those using cannabis for its myriad of health benefits may [incorrectly] perceive that cannabis is helping their condition instead of exacerbating it.”[]
There is also the possibility that some cyclic vomiting patients have been mislabeled. To correctly diagnose patients, the review authors recommend starting with “a complete history of cannabis use including age of initial onset, amount used per week, and behavioral factors associated with symptom relief (such as hot showers). Following this, underlying medical etiology of the symptoms should be ruled out using laboratory evaluation and imaging.”
When diagnosis is in question, you may want to recommend a trial of cannabis abstinence to your patients, says Dr. Venkatesan. However, she suggests attempts at reduction may prove more fruitful than complete abstinence.
"The first thing the provider should find out is: Did the cannabis use precede the vomiting? [Then ask], what is the frequency? What is the potency of the cannabis product? Are they using cannabis concentrates?"
— Thangam Venkatesan, MD
She emphasizes that frequency must be high: “If somebody is using [cannabis] two times a month or even once a week, it’s unlikely to result in CHS,” Dr. Venkatesan continues. “But suppose we determine that this person is a heavy cannabis user, with daily, or near daily use, preceding the onset of vomiting, and high potency. The recommendation would be to reduce that cannabis use.”
Dr. Venkatesan adds that patients are unlikely to stop using cannabis cold turkey, “particularly because of the perception that it is helping [their CVS symptoms].” Additionally, she notes these patients should be started on medications for cyclic vomiting. “The guidelines recommend using amitriptyline as prophylactic therapy, and then you would also give them abortive or rescue therapy to try and stop those episodes. Then you follow those patients over time.”
Recognize comorbidities
Patients may be using cannabis to relieve stress and anxiety, which should also be taken into account, Dr. Venkatesan notes.
“Patients can be in a state of panic, which is part of a CVS episode. While we are looking at the vomiting, it’s also very important not to dismiss them and say, ‘Oh, just go stop the cannabis.’ The psychological burden is something that should not be overlooked.” In these cases, Dr. Venkatesan advises additional evaluation and treatment from a psychologist or a mental health expert.
Questions remain about CHS and its connection to CVS. According to the Journal of Medical Toxicology authors, “CHS is under-recognized due to a combination of factors including the paradoxical use for treatment of nausea and vomiting, the stigma associated with cannabis use, and the illegal status of cannabis in many regions leading to under-reporting of use.”[]
As with many burgeoning yet not fully understood disorders, future research should focus on investigating the underlying mechanism and predisposing factors of CHS, to “further understand the consequences of high-dose cannabinoid use and dysregulation of the endocannabinoid system.”[]
“The data is just not fully there yet,” Dr. Venkatesan says.
What this means for you
Even among cannabis users, episodes of cyclic vomiting may not always mean cannabinoid hyperemesis syndrome (CHS). Evaluate patients’ frequency of cannabis use, and cannabis potency, to help diagnose CHS. Consider medications for cyclic vomiting while monitoring the patient in the long term, and encourage reducing cannabis use as appropriate.