Marijuana can be a valuable therapeutic tool for the nausea and vomiting that accompany chemotherapy, but it also can cause hyperemesis.
Would you be surprised to learn that 49% of Americans say they have tried marijuana?1 (But did all of them inhale?) Even though marijuana is the most illicitly used drug in the world, some states have legalized it for medical uses (such as anorexia, nausea, and vomiting) and others for recreational use.1
Marijuana can be a valuable therapeutic tool for the nausea and vomiting that accompany chemotherapy. But did you know it can paradoxically cause hyperemesis?
Let’s ask some important questions:
1. How can I diagnose cannabinoid hyperemesis syndrome?
This is a clinical diagnosis, and there are no lab or imaging tests.1 Patients typically are younger (younger than 50 years) and are not novices or first-time users of marijuana (usually more than 1 year of use). They evidence 2 prominent features when they present to medical attention: they have severe cyclic nausea and vomiting (often worse in the morning), and they compulsively take hot showers or baths to relieve their symptoms.
Prior to the onset of nausea and vomiting, patients can be anxious and agitated. When the vomiting follows, it is resistant to ondansetron and promethazine. But the vomiting is relieved by the hot bathing or showering, and the “hotter the better.”1
History is key to the diagnosis. Most of these patients frequent the emergency department for recurrent nausea and vomiting. They have had extensive and otherwise negative GI workups.
Most patients’ symptoms resolve in 24 to 48 hours. Some take longer (a week to a month).1 But there is an important caveat: restarting cannabis causes the symptoms to return.1
2. Why the compulsion to hot bathe or shower?
There are 2 theories as to why, but no proof. Marijuana affects the thermoregulatory center in the brain.1 Too much marijuana might have a negative effect on this portion of the brain. If cannabis alters the hypothalamic sensing of ambient temperature, heat may restore equilibrium. Resolution of the thermoregulatory disturbance may occur with the hot water for a while, but it must be used over and over again.
The other theory is called the “cutaneous steal syndrome.”1 Hot water causes vasodilatation and as a consequence decreases splanchnic blood flow, possibly alleviating the abdominal pain, nausea, and vomiting.
3. Why is this clinical entity important?
A number of observations may serve as an answer to this question. Because marijuana use is so prevalent, we are all going to encounter cannabinoid hyperemesis syndrome. An extensive GI workup may be obviated by a good history. None of us wants a patient in this category inappropriately going to surgery. Management after diagnosis is straightforward: fluids, counseling, and marijuana cessation.
Be on the lookout, you are going to see the vomiting syndrome, so do not forget to ask about the marijuana and hot bathing and showering.
• Cannabinoid hyperemesis syndrome is a clinical diagnosis, and there are no lab or imaging tests. History is key to the diagnosis.
• There are 2 theories as to why persons with the syndrome feel compelled to hot bathe or shower, but no proof.
• This clinical entity is important for several reasons, including nobody wanting a patient inappropriately going to surgery.
1. Lu ML, Agito MD. Cannabinoid hyperemesis syndrome: marijuana is both antiemetic and proemetic. Clev Clin J Med. 2015;82:429-434.