ASA 2026: Not All Cannabis Is Equal: Inhaled Marijuana Increases Propofol Requirements for Endoscopy

MedicalResearch.com: What is the background for this study? 

Dr. Basavana Goudra

Dr. Goudra: Cannabis use is increasingly common, and anesthesia providers are consequently encountering more patients who use cannabis before procedural sedation and anesthesia. This has become an important perioperative issue because cannabinoids can have complex effects on the central and peripheral nervous systems, and their pharmacologic effects vary with the dose, potency, frequency, and route of administration.

A review of the anesthetic implications of marijuana use emphasized that the pharmacokinetics of cannabinoids are difficult to predict and that the route of delivery is one of the factors influencing the effects of THC. (Alexander JC, Joshi GP. A review of the anesthetic implications of marijuana use. Proc (Bayl Univ Med Cent). 2019 May 21;32(3):364-371. doi: 10.1080/08998280.2019.1603034. PMID: 31384188; PMCID: PMC6650211.)

There has also been growing evidence that cannabis users may require more anesthetic medication. For example, a prospective randomized study by Flisberg and colleagues found that regular cannabis users required a significantly higher total propofol dose to achieve satisfactory laryngeal mask insertion—approximately 314 mg compared with 263 mg in non-users. Interestingly, the propofol dose needed to achieve a BIS below 60 alone was not significantly different. This suggested that the effect might depend on the clinical endpoint being evaluated. (Flisberg P, Paech MJ, Shah T, Ledowski T, Kurowski I, Parsons R. Induction dose of propofol in patients using cannabis. European Journal of Anaesthesiology | EJA. 2009 Mar 1;26(3):192-5.)

The issue has also been studied specifically during gastrointestinal endoscopy. Imasogie and colleagues reported that cannabis exposure was associated with substantially greater propofol requirements during endoscopy. Their study of 318 patients found mean propofol doses of 0.33 versus 0.18 mg/kg/minute in cannabis-exposed and unexposed patients, respectively, and daily cannabis users required more propofol than less frequent users. (Imasogie N, Rose RV, Wilson A. High quantities: Evaluating the association between cannabis use and propofol anesthesia during endoscopy. PLoS One. 2021 Mar 4;16(3):e0248062. doi: 10.1371/journal.pone.0248062. PMID: 33661987; PMCID: PMC7932135.)

More recently, a 2025 systematic review and meta-analysis of eight studies involving 2,268 patients found that cannabis users required an average of approximately 47 mg more propofol than non-users. For patients undergoing endoscopic sedation, the pooled difference was approximately 53 mg. However, the authors emphasized substantial heterogeneity and the need for caution in interpreting these findings. (Baker MB, Binda DD, Nozari A, Kennedy JM, Dienes E, Baker WE. Quantitative analysis of propofol dosage in cannabis users: a systematic review and meta-analysis. Journal of Clinical Medicine. 2025 Jan 28;14(3):858.)

Against that background, we asked a more specific question: Does the route by which cannabis is consumed matter?

We retrospectively reviewed 280 endoscopic procedures at a single center. Complete cannabis-route information was available for 264 patients: 217 non-users, 38 inhalation users, and 9 oral users. The primary outcome was the propofol induction dose.

MedicalResearch.com: What are the main findings?

Dr. Goudra: The main finding was that not all cannabis users appeared to have the same anesthetic requirements.

Overall, inhalation users received a mean propofol induction dose of 168.5 mg, compared with 138.7 mg in non-users. Oral users received 114.2 mg. Importantly, when all cannabis users were combined into a single group, there was no significant difference compared with non-users. The difference became apparent when cannabis use was separated according to route.

The procedure-specific findings were particularly interesting. During colonoscopy, there were no meaningful differences between the groups. During EGD, however, patients reporting inhaled cannabis use required a mean of 192.8 mg of propofol, compared with 151.4 mg in non-users. Oral users had a mean dose of 145.0 mg.

So, our study adds an important dimension to the existing literature: the relationship between cannabis and propofol requirements may depend not simply on whether someone uses cannabis, but on how the cannabis is consumed and potentially on the type of endoscopic procedure being performed.

MedicalResearch.com: Is cannabis, in various forms, routinely screened for pre-anesthesia?

Response: Yes. In our practice at Thomas Jefferson University Hospital, cannabis use is routinely addressed during the pre-procedure assessment. Both the pre-procedure nursing staff and the anesthesia providers specifically ask about cannabis use and document the information in the medical record.

We try to obtain more than simply a yes-or-no answer. When possible, we document the route of administration, amount and frequency of use, duration of the habit, and particularly the time of the last use. We also try to determine the type and potency of the product when that information is available.

The timing of the last exposure is particularly important. If a patient tells us that they have smoked cannabis immediately before coming for the procedure, we discuss the potential anesthetic and cardiovascular risks with the patient and, in our practice, we will typically cancel and reschedule the procedure rather than proceed with elective anesthesia immediately after acute cannabis use.

This is not simply about the potential effect on propofol requirements. Recent cannabis exposure may have cardiovascular and physiologic implications, and those effects can vary according to the dose, timing of exposure, potency and composition of the product, route of administration, and concomitant medications or other drugs. The timing of the last exposure therefore becomes an important part of our pre-anesthetic assessment.

Importantly, when I say that we routinely screen for cannabis, I mean clinical screening through questioning and documentation, not routine blood or urine toxicology testing.

This experience was also one of the reasons we became interested in the question addressed by our study. If we are already asking patients whether they use cannabis, perhaps we should also be asking how they use it. A patient who uses inhaled cannabis may have a different perioperative profile from someone who uses an oral preparation, and our study suggests that route may be relevant when considering propofol induction requirements.

MedicalResearch.com: What should readers take away from your report?

Response: The main message is that cannabis use should not be treated as a simple yes-or-no item in the pre-anesthesia assessment. Our findings suggest that the route of cannabis administration may be clinically relevant when anticipating propofol requirements.

Previous studies have shown that cannabis users may require more propofol or other anesthetic agents. For example, a prospective study found that regular cannabis users required significantly more propofol for laryngeal mask insertion, and an endoscopy study found higher propofol requirements among cannabis users, particularly with more frequent use.

Our study adds another dimension to that literature. When cannabis users were considered as one group, the difference was not significant; however, when we separated patients according to route of administration, patients using inhaled cannabis required higher induction doses, particularly during EGD. The oral group was small, so those findings should be interpreted cautiously.

I would therefore not suggest that anesthesiologists simply give every cannabis user a larger dose of propofol. Rather, the history should be more granular—including the route, amount and frequency of use, duration of use, and time of last exposure. These details may help the anesthesia team anticipate variability in anesthetic requirements and potential perioperative risks.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: I think the most important next step is to move beyond simply classifying patients as cannabis users or non-users and to prospectively characterize cannabis exposure in much greater detail.

Future studies should include larger numbers of patients and specifically examine route of administration—particularly inhaled versus oral cannabis—as well as dose, frequency and duration of use, product potency, and the time since the last exposure. Our oral cannabis subgroup was small, so larger studies will be particularly important to determine whether the findings we observed with oral preparations are reproducible.

I would also recommend prospective, multicenter studies using standardized definitions of cannabis exposure and standardized endpoints for propofol dosing and depth of sedation. This is important because the existing literature is heterogeneous. For example, prior studies have demonstrated increased propofol requirements in cannabis users, but they have differed in their patient populations, definitions of cannabis exposure, and anesthetic endpoints.

Another important area is the relationship between acute versus chronic cannabis exposure. Future research should determine whether recent use has an independent effect on anesthetic requirements or whether the observed differences are primarily related to chronic exposure and tolerance.

Finally, I think future studies should look beyond propofol dose alone and examine perioperative cardiovascular, respiratory, and sedation-related outcomes. A better understanding of how route, potency, dose, and timing of cannabis exposure interact with anesthetic requirements and perioperative risk could ultimately help us develop more individualized approaches to patients who use cannabis.

Ultimately, the goal should be to develop evidence-based, route- and exposure-specific guidance for anesthesiologists rather than treating all cannabis users as a single homogeneous group.

MedicalResearch.com: Is there anything else you would like to add? Any disclosures?

Response: For my colleagues in anesthesia and procedural medicine, I would emphasize that cannabis should not simply be treated as a yes-or-no checkbox. Route, amount, frequency, duration of use, potency, and especially the timing of the last use can all be clinically relevant. Our study suggests that the route of cannabis administration may also influence anesthetic requirements, although further prospective research is needed.

For patients, my message is even simpler: please tell your anesthesiologist and procedural team about your cannabis use—whether it is smoked, vaped, eaten, or taken in another form. Do not assume that cannabis is irrelevant because it is legal, medicinal, or something you use regularly. And if you have used cannabis shortly before a planned procedure, tell your healthcare team exactly when and how much you used. That information can help us make your anesthesia and procedure safer.

The most important message is: don’t hide cannabis use from your anesthesia team. We are not there to judge you—we need the information to take care of you.

Cannabis is not one drug, and cannabis users are not one homogeneous group. For patients undergoing anesthesia, “How do you use cannabis, how much do you use, and when was the last time you used it?” may be just as important as “Do you use cannabis?”

I have no relevant financial conflicts of interest or commercial relationships related to cannabis products or propofol to disclose.

For more on cannabis and surgical outcomes, see this MedicalResearch.com overview of cannabis use disorder and complications after surgery.

The information on MedicalResearch.com is provided for educational purposes only, and is in no way intended to diagnose, cure, or treat any medical or other condition. Some links are sponsored. MedicalResearch.com and Eminent Domains Inc. do not warrant or endorse products or claims made by third party links. Always seek the advice of your physician or other qualified health provider and ask your doctor any questions you may have regarding a medical condition. In addition to all other limitations and disclaimers in this agreement, service provider and its third party providers disclaim any liability or loss in connection with the content provided on this website.