Cyclic vomiting syndrome (CVS) is a chronic disorder of gut brain interaction  (DGBI) diagnosed by clinical criteria called Rome criteria as there are no biomarkers [blood tests or x-ray tests] that can be used to detect this condition. CVS is common and affects about 2% of the US population. CVS affects both sexes and can occur at all ages. CVS includes stereotypic episodes of severe nausea and vomiting that can last from a few hours up to a week. Other  symptoms include abdominal pain,feelings of panic, feeling hot and cold, sweats and diarrhea. CVS consists of 4 phases which include the a) prodromal b) emetic c) recovery and d) an interepisodic phases. Though many patients return to normal health in between episodes, some patients continue to experience mild nausea and/or abdominal pain in between episodes. In addition, patients with CVS also have other comorbidities such as migraine headache, autonomic dysfunction, anxiety and depression which need to be identified and managed.

CVS episodes can be mild, but a subset of CVS patients will need treatment either in the emergency room or the hospital due to the severity of their symptoms. Recent guidelines on the management of CVS recommend treatment in the form of either abortive/rescue medications or prophylactic medications to prevent episodes of CVS. Abortive/rescue therapy should be taken as early as possible during the prodromal phase, for maximal efficacy. Medications that are used to abort or stop an attack of CVS include ondansetron, triptans (intranasal sumatriptan), aprepitant (emend), and anxiolytics such as lorazepam. The first-line treatment in the prevention of CVS is amitriptyline which is a tricyclic antidepressant. Other medications used to prevent CVS include topiramate and newer medications like aprepitant/emend.  Choice of these medications should be based on individual patient characteristics and side effect profile and should be made after a thorough discussion with the provider. Though there are no randomized controlled studies in CVS in adults, trials are now underway for the development of better therapies as well as delivering standard medications through alternative routes such as the use of an inhaler.

CVS can be quite debilitating and has a significant negative impact on patients, families and the healthcare system. Short term disability, absenteeism from work and school are common. There is a significant cost burden due to CVS for both the patient as well as the health care system. Further funding and  research to better understand the cause of CVS and develop better treatment is critical to improve outcomes.

Cannabis use in CVS is quite prevalent with approximately 40% of patients reporting its use. Patients report relief from nausea, abdominal pain, vomiting and feelings of panic and anxiety with cannabis use. However, there are increasing reports of hyperemesis attributed to heavy chronic cannabis use. Cannabinoid hyperemesis syndrome (CHS) is a term that was recently coined based on reports of hyperemesis in association with heavy cannabis use. Young males who use cannabis on a daily or near-daily basis are most commonly diagnosed with this condition. CHS symptoms are similar to CVS except for the chronic heavy cannabis use. The peculiar pattern of hot-water bathing multiple times a day is seen quite often with CHS, although it is also seen in ~ 50% of patients with CVS who do not use cannabis.

While cannabis has been used for centuries, cannabis products that are now available on the market differ that they contain very high concentrations of tetrahydrocannabinol [THC]. THC is the active psychotropic ingredient in cannabis and is responsible for the “high” and also has antiemetics properties. The use of cannabis products with high concentrations of THC, particularly cannabis concentrate can be particularly problematic. The recommended treatment is complete abstinence from cannabis for several months though patients are reluctant to do this due to perception about its benefits. If the hyperemesis is due to cannabis, there will be resolution of episodes over a period of time after cessation though this can take up to a year. Patients with possible CHS should also be offered treatment for CVS and be counselled about abstaining from cannabis. Whether CHS is a subset of CVS remains to be determined. Unfortunately, there is limited knowledge about CHS and more research is required before answering several important questions about how cannabis affects human health and its role in hyperemesis.