David Casarett MD

 

The problem:  As cannabis use has increased, so too has the incidence of side effects as naive users try cannabis for the first time.  Emergency rooms in particular have seen increases in the incidence of cannabis-related side effects among their patients. 

 

Why do this study?  Although the side effects of cannabis are generally minor and well-described, not much is known about the incidence of these side effects as a function of routes of administration. In particular, we don’t know whether certain routes of administration are responsible for a disproportionate number of emergency room visits for toxicity.  (The conventional wisdom is that, because of their slow and variable absorption, edibles are especially likely to produce unwanted side effects.  However, this hasn’t been studied in a rigorous way in the emergency room setting).

 

The study: The authors did a chart review of all patients seen in the emergency room of an urban medical center in Colorado over 5 years (2012-16).  Of 9,973 visits that included a code for cannabis use, cannabis played a role in that illness in 2,567 visits (25.7%).  Of those, only a small minority (238; 9.3%) were attributable to edibles.  Edibles were more likely than inhaled cannabis to be linked to most symptoms, including acute psychiatric symptoms (18.% vs. 10.9%), intoxication (48% vs. 28%) and cardiovascular symptoms (8% vs. 3.1%).  On the other hand, inhaled cannabis had higher rates of hyperemesis syndrome compared to edibles (18% vs. 8.4%)

 

Conclusions:  Inhaled cannabis is responsible for significantly more emergency room visits than edibles are. However, among those who go to the emergency room, edibles are responsible for a disproportionate share of psychiatric symptoms, acute intoxication, and cardiovascular symptoms.

 

What does this study add? The conventional wisdom holds that edibles are risky because absorption is delayed, and because naïve users may be tempted to re-dose before the last dose achieved its peak effect.  And in fact edibles seem to be more likely to be associated with several adverse effects.  On the other hand, this study suggests that edibles are responsible for only a minority of emergency room visits.

 

Funder: The Colorado Department of Health

 

Author conflicts: None

 

Commentary:

This is a well-done retrospective that relied entirely on medical record reviews.  That creates some problems and challenges, especially since medical records aren’t usually complete.   Some patients may not have reported their cannabis use, and may not have reported illicit drug use. So it’s hard to say for certain whether the associations reported here are real.

​

The other thing to keep in mind in interpreting this study is that it looked only at people who came to the emergency room.  That is, it’s not a study of all edible users, just those who came to the emergency room.  In fact, the authors acknowledge this, and report that although edibles were responsible for approximately 10% of emergency room visits, they were responsible for less than 1% of sales in Colorado between 2014-2016.  So it’s possible that edibles are in fact more likely to lead to toxicity-related emergency room visits.