Cannabis Hyperemesis Syndrome

Weed can make you barf?

Cannabis is indispensable for millions of patients to help alleviate a variety of gastrointestinal symptoms including colitis symptoms, gastroparesis, irritable bowel syndrome and, particularly, chemotherapy induced nausea and vomiting. It is used with great success for migraines and is also used to treat a miserable, related syndrome called cyclic vomiting syndrome. Cannabis is not recommended for use during pregnancy, despite the fact that it is highly effective for the nausea and vomiting associated with morning sickness, which makes it a popular option.

So, how can cannabis cause vomiting? What is this increasingly diagnosed condition called cannabis hyperemesis syndrome (CHS)?

Paradoxical and biphasic reactions

Some drugs have paradoxical reactions, meaning that a small percentage of patients experience effects that are opposite from the usual and intended effects. For example, Benadryl (diphenhydramine) makes most people sleepy, which is why it the active ingredient in Tylenol PM (which is a crappy sleeping medication - but that is for another day). However, a small percentage of patients become wired and physiologically excited after consuming Benadryl. Another example: barbiturates are usually extremely sedating but, a subset of people become highly activated after taking them.

Moreover, some drugs are “biphasic” meaning that in low doses they have one effect and in higher doses they have a different effect. Using cannabis to treat anxiety is the perfect example of this. When used at a low dose it helps alleviate anxiety for most people. At high doses cannabis can cause severe anxiety and may even lead to a full-blown panic attack. Any of us who have accidently consumed too large of a dose, such as too much brownie batter or an unmarked edible, can attest to this fact.

Given this framework, it is not difficult to understand that cannabis might alleviate nausea at low doses and might exacerbate it at high doses. The most dramatic example of this is when people “green out” meaning that they acutely consume much too high a dose of cannabis. They can spend the rest of the evening barfing uncontrollably – it is ugly to witness. This particular reaction is best considered a toxic overdose, and it demonstrates that cannabis can cause nausea and vomiting. Cannabis hyperemesis is a chronic cannabis induced vomiting syndrome among heavy, regular cannabis users that is being increasingly recognized.

Cannabis Hyperemesis Syndrome (CHS)

CHS largely afflicts a minority of longstanding, heavy users of cannabis. It is characterized by severe, episodic nausea and vomiting, often accompanied by abdominal pain and weight loss. Curiously, people report taking hot showers to alleviate the symptoms, which can be a clue to the diagnosis.

This syndrome does not occur with people taking an occasional, sociable puff of cannabis at a party. This syndrome does not often occur with medical patients taking a modest dose of cannabis every day, such as a small, regular dose of an edible or a puff or two for chronic pain. It almost predominantly occurs in heavy cannabis users and most typically occurs in young men aged 16-34.

People with CHS often end up in the emergency room, possibly several times a month, with electrolyte abnormalities, severe dehydration and, occasionally, more ominous symptoms, such as muscle breakdown or, uncommonly, seizures. There can also be acute kidney failure, esophageal injuries from intensive vomiting, and pneumomediastinum, which is when you throw up so intensely that you tear a hole inside of your chest.

Is it accurately diagnosed?

Cannabis hyperemesis has gone from being underdiagnosed to being over diagnosed. We didn’t have a definition of it until 2004 so, before then, it was never diagnosed. Even after it was clearly defined as a syndrome, emergency room department doctors didn’t associate cannabis – a drug known for helping nausea and vomiting in cancer patients – as the cause of these wretched symptoms. Also, patients were not particularly forthcoming about their cannabis use due to the war on drugs which made an accurate diagnosis less likely. Who wants to risk getting into trouble by admitting to cannabis use? You can’t have a diagnosis of CHS without the cannabis part.

Today, with more scientific understanding, more clinical experience, more accepting attitudes toward cannabis use, and more general recognition, it is very frequently diagnosed in the emergency department.

The increased incidence of CHS likely has to do with the fact that cannabis is much stronger that it used to be and because there are now more people are using it heavily – both risk factors for CHS.

At the same time, given that it is now a fashionable diagnosis that doctors frequently read about in the press, many patients who present with vomiting, and who have ever admitted to cannabis use, at any point, can be given this diagnosis, without much deeper thought. This leads to overdiagnosis.

The problem with this automatic, default diagnosis of CHS is that it might not be accurate. It is unhelpful to give someone the wrong diagnosis. For example, there is a syndrome called “Cyclic Vomiting Syndrome” (CVS) which presents in almost the exact same manner that CHS does. One main difference is that with CVS there is less of a history of trying to self-treat with hot showers. Otherwise, they can appear in an identical manner.

CVS is a complex syndrome of nausea and vomiting, that is physiologically related to migraines. Migraines are one of the conditions that medical cannabis works particularly well to alleviate. In fact, many people use cannabis to treat CVS with good benefit.

This means that a patient can often present with a) cannabis use and b) nausea and vomiting and therefore will almost automatically be given a diagnosis of CHS. Yet, the diagnosis won’t actually be CHS. It will be CVS, which is being treated with medical cannabis. This is a perfect example of how CHS can be misdiagnosed. The treatments for these two conditions are overlapping, so misdiagnosing isn’t the end of the world.

How to treat CHS

The only way to differentiate between CHS and CVS is to stop using cannabis for 3-6 months. If the problem resolves, it was CHS. If the problem continues, without any cannabis use, it is CVS. As such, the only true diagnostic tool for and treatment of CHS is complete cessation of cannabis use.

Unfortunately, very few heavy cannabis users manage to remain abstinent even for the 3-6 months it takes to develop an accurate diagnosis. In my book, this can be considered an example of cannabis addiction. My best definition of addiction is, “continued use despite negative consequences”. Not being able to stop a drug that is likely responsible for landing you in the E.D. several times a month, with great misery and expense, certainly falls into the category of “continued use despite negative consequences”. I have had several patients go through this exact scenario and it is awful to witness.

Short of cannabis cessation, there are standard treatments for CHS. We often start with aggressive hydration, which helps restore kidney function, and with repletion of electrolytes which can be dangerously depleted, such as magnesium, phosphorous, and potassium. Imaging is done to make sure there isn’t anything else going on such as pancreatitis or cholecystitis (i.e., gallbladder inflammation).

In CHS, traditional medications for nausea tend to be less effective, but we still rely on the usual meds: Compazine (prochlorperazine) and Zofran (ondansetron). When these don’t work, we often must escalate to more heavy-duty medications such as intravenous Haldol (haloperidol) which is an anti-psychotic drug, and intravenous Ativan (lorazepam) which is a strong sedative benzodiazepine. Interestingly, the nausea can often respond to capsaicin cream rubbed onto the belly, due to the specific types of receptors thought to be involved in CHS (i.e., the TRPV1 receptors, otherwise known as the capsaicin receptors). As mentioned, hot baths or showers can provide relief as well.

How do you get people to stop using cannabis when they really need to, such as in cases of CHS or other clinical conditions such as cannabis addiction or psychosis? We are not good at it. There are no FDA approved medications for this. It is often difficult to convince a patient that their use is a problem. Even if blatantly misused, they can convince themselves that their use is still “medical”.

Cannabis cessation among heavy, daily users can result in significant withdrawal symptoms such as irritability, insomnia, anxiety, and lack of appetite (which, significantly, are the opposite of what people use cannabis to treat in the first place). Just as with opioids or alcohol, the unpleasantness of the withdrawal symptoms can promptly lead people back to use.

The current behavioral treatments for cannabis misuse are not particularly effective. They include psychotherapy such as CBT (“cognitive behavioral therapy”), support groups (such as the cult-like Marijuana Anonymous or groups such as Smart Recovery), and the utilization of other medications such as gabapentin or anticonvulsants, all of aren’t particularly effective and which have serious side effects.

Future directions

How can we lessen the harms and suffering associated with CHS? I suggest a harm reduction framework. We can encourage cannabis users to tone down the volume and frequency of their use so as to keep the consumption at a sustainable level. Lots of people puff away all day with decreasing benefit and accumulating harm. We can stop, as a society, fetishizing high THC above all else. If we bred cannabis to be comprised of somewhat less THC and, instead, to include more of the other, healthful cannabinoids, such as CBD, CBC, and CBN, then there might be fewer problems such as CHS. We should encourage people to avoid concentrates as these are extremely potent, often up to 95% THC. This seems like a perfect set up for CHS, as well as for cannabis addiction and, potentially, psychosis.

We should encourage patients to solely procure their cannabis through the legal market so that we know it has been tested. We can thus be reasonably assured that this cannabis is free of heavy metals, lead, pesticides and fungus, none of which can possibly be helpful in cases of CHS.

Doctors can do a better job of not jumping to the conclusion, in the Emergency Departments, that any syndrome of vomiting in a cannabis user is CHS, so we don’t continue to misdiagnose it. If someone looks like they have CHS but can’t stop using cannabis for long enough to make an accurate diagnosis, we need to devote the necessary resources to treating this problem, as we should with any other addiction.

We must continue to work to lessen the stigma surrounding cannabis use so that people can readily admit to their consumption to their doctors. This way they can ask for help if they need it. The more our society can come to common ground around cannabis, about the harms as well as the benefits, the more we can have helpful communication instead of discord. There will be much less confusion and disagreement around cannabis related problems, including cannabis hyperemesis syndrome.