Cyclic vomiting syndrome and cannabis use

Steve Wartenberg: Welcome back. This is our ongoing series on cyclic vomiting syndrome with Dr. V. I'm Steve Wartenberg, and this is Thangam Venkatesan. Today's topic is cannabis use and CVS. There's a lot of information and a lot of misinformation out there on this topic. Our goal is to give you all the facts you need to know. Let's start with the basics. What are cannabinoids, and why are they so important as they relate to CVS?

Thangam Venkatesan, MD: Essentially, cannabinoids are compounds that have affinity for something that we call cannabinoid receptors that are present in our body. It's distributed all over our body, including various areas of the brain that are very important for multiple functions, including regulation of stress, nausea, and vomiting. There are three types of cannabinoids. We have phytocannabinoids. Phyto means plant, and this refers to cannabis, which we get from the plant. We also have something called endocannabinoids. Endo is inside, and we actually all synthesize marijuana-like substances, which are called endocannabinoids. These also act on the same cannabinoid receptors and are very important for body homeostasis and really allows us to function normally. Those are also very important. Then finally, we have synthetic cannabinoids such as Marinol and so on that are actually manufactured and sold.

Steve Wartenberg: How widespread is the use of marijuana, because here in Ohio, just less than a month ago, we had a statewide vote to legalize recreational use of marijuana, which is a trend across the country and other states?

Thangam Venkatesan, MD: If you look at data over the last two decades, we've really found that cannabis use has significantly increased in many age groups. If you look at the age group between say 18 to 25 year olds, now, about one in four individuals in this age group have used cannabis within the last 30 days. If you look at people who are 26 and above, about one in 10, so 10% of the US population have used cannabis within the last 30 days. Another really important thing is that the studies where they've looked at the potency of cannabis, if you look at people who used weed or a joint in the nineties, the amount of THC ... Now, THC is tetrahydrocannabinol. It is what we call the psychoactive ingredient in cannabis. The concentration of THC in a joint was around 4% about 20 years ago. Now, it's 14%

Steve Wartenberg: Tripled, more than tripled.

Thangam Venkatesan, MD: Exactly. In fact, because of the way that we really manufacture and produce cannabis, you have what's called cannabis concentrate. You can get 65 to 85% THC in a product. The cannabis product that you're using now is entirely different from what you were using in the nineties and maybe even in 2000.

Steve Wartenberg: How does this impact people and your patients?

Thangam Venkatesan, MD: I certainly think it's a problem because now, people and patients who use it are actually using high-potency products. They're also maybe using it more frequently. While cannabis can have some good or beneficial effects if used infrequently, it can also have paradoxical side effects. For instance, cannabis is actually an anti-emetic, so it can prevent nausea and vomiting. However, if you use very high doses and very high concentrations of cannabis, it can lead to something called hyperemesis. That's something that people ought to know. I think the risk of addiction and dependence and so on goes up as you use these high-potency products that are now being marketed.

Steve Wartenberg: Let's take a little step back. When you have a new patient, what do you kind of ask your patient about their cannabis use?

Thangam Venkatesan, MD: When they come to me, they often come with symptoms of nausea and vomiting, and it is true that many of them smoke cannabis. However, one of the things I really want to ask them about is one, how frequently are you using cannabis? For instance, if somebody says that they're using it daily or near daily, that would be a problem. If somebody says ... I specifically ask them if they're using cannabis concentrates because to me that's a red flag. Like I said, the amount of THC in a regular joint was around 4%, and if they're using something which has 65 or 85% THC, then certainly the effects are going to be very profound and different from what you would expect if you were just using a lower-potency cannabis product.

Steve Wartenberg: Now, are patients using this to reduce or prevent symptoms of their CVS?

Thangam Venkatesan, MD: Yes. Cannabis has been used forever. Like I said, it's not just cannabis, but endocannabinoids or cannabinoids. There are multiple studies that have shown that they have anti-emetic effects, and when somebody is vomiting and you give them cannabis or a cannabinoid, can actually stop the vomiting. Unfortunately, when you start using it daily, it can have different effects in a subset of patients and can lead to something called hyperemesis.

Steve Wartenberg: You mentioned Cannabinoid Hyperemesis Syndrome, which I didn't pronounce even close. Say it, and then what is it?

Thangam Venkatesan, MD: It's Cannabinoid Hyperemesis Syndrome or CHS, so you can just call it CHS.

Steve Wartenberg: CHS. Okay.

Thangam Venkatesan, MD: This was actually a term that was coined maybe about a decade ago based on reports that patients with Cyclic Vomiting Syndrome were using cannabis. About 40% of patients with CVS do use cannabis. Unfortunately, the literature doesn't really support cannabis leading to hyperemesis, and it's sort of murky. Be as it may, we have this new diagnosis called Cannabinoid Hyperemesis Syndrome. The first case reports of this were actually from Australia, Adelaide in Australia. There were these nine patients who used cannabis, and when they abstained from cannabis, they got better, and they were followed for about one or two years. There was another peculiar behavior, where they found that these patients would actually be found in a hot shower, and they would be having hot showers all day long. This was called a pathological hot-water bathing behavior, which was thought to be what is called pathognomonic of cannabis use. CHS has the exact same symptoms as CVS, and we think it's a subset of CVS, which is made worse by chronic cannabis use.

Steve Wartenberg: Chronic cannabis use can ... The people do it to reduce their symptoms, but it has the opposite effect and can lead to this hot-water bath thing because somehow that feels better to have the hot water pouring on you when you're having these episodes.

Thangam Venkatesan, MD: It's almost a compulsive bathing behavior, which is sort of learn-itself learned, and patients will actually go and have a hot shower or just sit in the hot bath all day long. What that hot bath does is actually makes them feel better, at least transiently. This is very unique to patients with Cyclic Vomiting Syndrome. Now, about 10 years ago, there were some investigators who said, oops, now this pathological bathing behavior is only associated with cannabis use, but however, that's not true. We have actually done studies, and I have numerous patients with Cyclic Vomiting Syndrome who don't use cannabis at all, who also exhibit the same hot-water bathing behavior. About half the patients with CVS who don't use cannabis at all also exhibit this hot-water bathing behavior.

Steve Wartenberg: What's the bottom line that you tell your patients about cannabis use what they should and shouldn't do?

Thangam Venkatesan, MD: At this point, when I see my CVS patients, I actually tell them to cut down cannabis and hopefully, even stop it. I think the other important thing is obviously to continue to treat them with medications and also treat other comorbidities like anxiety and so on because very often, patients actually use cannabis as either an anxiolytic and to control nausea and so on and so forth.

Steve Wartenberg: Oh, that's a great intro for our next episode that we're going to do next, which is about some of these stress and anxiety issues. Stay tuned for that one everyone. Thank you for filling us in on what people should know and the facts about cannabis use in CVS.

Thangam Venkatesan, MD: Thank you, Steve.
 
Steve Wartenberg: Thanks for watching and stay tuned for more episodes on what you need to know about CVS with Dr. V.

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