Like many EDs worldwide, the normalization of cannabis consumption has led to an increase in the number of cannabis-related consults in the ED (positive delta from 2.3 to 13.3 cases per 100,000 ED visits in the USA from 2006 to 2013) [43]. In light of the severity of their symptoms, these patients often require increased monitoring and accompaniment. With average ED times of 13.9 h [26], these patients, who often do not fill the criterion for hospitalization, are bound to already chronically oversaturated EDs and add to the pressure on healthcare systems. Worse, frequent ED consultations have been shown to lead to cognitive bias from teams, which could trivialize symptoms and result in missed alternative diagnoses [45]. In light of these factors, and based on the above literature review, we proceeded to review the management of chronic cannabis users presenting to our ED with hyperemesis, nausea, and/or abdominal pain. In a bid to share with other acute care units, we will now present our internal guidelines, reflecting the current level of evidence.

Upon arrival to our ED, chronic cannabis users presenting with hyperemesis and nausea are first triaged to exclude any other conditions or signs of shock. If hemodynamically stable, they are redirected to a consult area with access to a nearby shower. IV access is set up, with bloods taken (a minimum of creatinine, urea, electrolytes, liver function tests, lipase, and full blood count are sent) and crystalloid-based rehydration started, as patients are usually unable to drink water due to nausea and/or emesis. An ECG is usually rapidly done, and the patient is given a PPI (PO, if tolerated). A thorough medical history is then obtained, and depending on whether CHS or CWS is suspected (the request for a warm shower is interpreted by us as diagnostic of CHS), a trial therapy with either 0.625 mg droperidol (IV) or haloperidol 0.05–0.1 mg/kg (IV/IM) for CHS or ondansetron (4 mg IV) for CWS is initiated. While currently not readily available in the author’s country of practice (available usually as a magistral preparation), the addition of capsaicin cream in the acute ED treatment may be highly beneficial at this stage: not only will the administration be demonstrated; the efficacy may actually improve ambulatory use.

The patient is then observed, and, depending on symptom progression, a second dose of butyrophenone neuroleptics may be added. If abdominal pain is present, standard analgesics are prescribed if CWS is suspected (for CHS, the use of topical capsaicin can again only be encouraged). During their time in our ED, these patients are generally seen by our frequent user (or complex case) team. Composed of specialized community outreach nurses, the aim is to identify what support systems the patient has in place in the community but also helps, in case of recurrent visits, determine what triggers have led to renewed consumption, to enable ambulatory follow-up and promote long-term abstinence. They are also trained, and take the time, to explain the diagnosis (including the pathophysiological pathways) and, for CHS, discuss the risk of developing a withdrawal syndrome (CWS) [44], all while promoting complete abstinence.

Upon resolution of acute debilitating symptoms, patients are usually discharged with a prescription for a magistral preparation of capsaicin cream (0.075%) (application on forearms and abdomen, 3–4 times daily), as well as a PPI, for CHS [26, 27, 40]. For suspected CWS, the only oral THC available in Switzerland is nabiximols (Sativex©) and is currently only licensed for multiple sclerosis [46]. Patients are therefore usually prescribed non-opioid analgesia, a reserve for gabapentin, with or without zolpidem; though after a review by our emergency psychiatry team, some are having psychological-associated symptoms. As there is always a risk for a missed diagnosis, prior to discharge, patients are reminded to present to the nearest healthcare center should their condition deteriorate or new symptoms develop. Our EMR system has been modified to automatically flag these patients when they present to our hospital, to ensure that healthcare teams have access to the long-term treatment plan (in patient notes). We believe this also helps reduce bias, as reading the notes illustrates the complexity of these syndromes.

Finally, after discharge, each patient is followed-up by our community outreach nurses, who review psychological, somatic, and social aspects of care. Follow-up is generally done on the phone, though community outreach nurses may see the patients within a dedicated clinic, to review progress, discuss symptomatic treatments, and prevent recurrent consultation to the ED [12]. Counseling may sometimes be required, though programs such as Marijuana Anonymous are currently non-existent in Switzerland, and so this is usually done with group behavioral therapy [30, 37]. A regular follow-up with the family doctor is also encouraged, as is physical activity, as this has been associated with prolonged abstinence [38, 40]. Should symptoms not resolve, or hospitalization be required for reasons other than purely symptomatic treatment (e.g., inadequate housing, previous psychiatric comorbidities, multiple failed attempts to quit), inpatient management including treatment (pain, nausea or insomnia for example), and psychosocial follow-up is governed according to a set protocol that includes a combination of the above [13].

Figure 2 summarizes our proposed emergency department therapeutic algorithm for cannabis use disorders.