Why regular marijuana users require more local dental anesthesia: Clinical implications for the dental care provider

Introduction

The increasing legalization and normalization of recreational marijuana use in the United States has introduced new clinical challenges for dental professionals, particularly those performing surgically invasive procedures such as tooth extraction, periodontal surgery, dental implant placement, and bone grafting. An increasing number of patients are now seeking dental treatment “high” or are under the influence of marijuana.¹ One recently reported clinical observation is that patients who regularly use marijuana are significantly more difficult to anesthetize.

While this phenomenon has long been anecdotal, emerging evidence from anesthesiology and oral and maxillofacial surgery literature now provides a clear physiologic explanation. Understanding why cannabis users require more local dental anesthesia is essential for predictable surgical outcomes, patient comfort, and medicolegal risk reduction.

Cannabis and pain modulation: The neurobiologic foundation

Tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, exerts its effects through the endocannabinoid system via CB1 receptors located throughout the central and peripheral nervous systems. These receptors play a critical role in pain perception, neurotransmitter release, and interaction with opioid and GABAergic pathways.²

With chronic cannabis exposure, CB1 receptors undergo desensitization and downregulation, with reductions of up to 75% reported in key brain regions. This adaptive tolerance diminishes the analgesic and sedative effects not only of cannabinoids themselves, but also of exogenous anesthetic agents routinely used in dentistry.

Evidence from sedation literature: Translating to local anesthesia

A pivotal study published in the Journal of Oral and Maxillofacial Surgery by Gangwani et al. evaluated anesthetic requirements in patients undergoing IV sedation who tested positive for THC. Cannabis users required 29% more fentanyl and 55% more propofol compared to nonusers. The authors concluded that the physiologic effects of recreational THC use alter the response to commonly used sedative and anesthetic medications.³

More recent perioperative data confirm that chronic cannabis users require a 15%–30% increase in propofol dosing, with daily users needing as much as 75.98 mg more propofol on average. These findings strongly support the concept of cross-tolerance, which is directly relevant to dental local anesthetics.⁴

Why this matters for local dental anesthesia

Local anesthetics such as lidocaine, articaine, and bupivacaine rely on effective sodium channel blockade combined with central pain modulation. In chronic marijuana users, altered central pain processing reduces endogenous pain inhibition, leading to unpredictable anesthetic outcomes.

Functional cross-tolerance and paradoxical hyperalgesia further increase anesthetic demand, resulting in patients reporting persistent sensation despite technically adequate nerve blocks or infiltrations.⁵ Although one study did find no effect of chronic marijuana use and its effect on local dental anesthesia, this was a small pilot study that was not blinded, used healthy noncarious teeth with electronic pulp testing, and relied on a patient questionnaire.⁶ Larger scale, double-blinded controlled studies are needed. 

Clinical guidance and risk mitigation

Professional medical organizations including the American College of Surgeons and the American Society of Anesthesiologists recommend discontinuation of cannabis use at least 72 hours to four weeks prior to surgery, depending on frequency of use, to reduce anesthetic requirements and perioperative risk.⁷ Recent guidance emphasizes that cannabis use has direct implications for procedural sedation due to altered anesthetic pharmacodynamics.

Practical implications for the dental care professional

Cannabis use should be considered a modifiable anesthetic risk factor. Best practices include explicit screening, anticipating higher anesthetic needs, allowing additional onset time, and considering adjunctive anesthetic strategies.

Conclusion

As marijuana use becomes increasingly prevalent, its impact on dental anesthesia can no longer be ignored. Regular cannabis users often require more local dental anesthesia due to CB1 receptor desensitization and altered pain processing. Recognition of this relationship allows clinicians to improve patient comfort and surgical outcomes.

Editor’s note: This article originally appeared in Perio-Implant Advisory, a chairside resource for dentists and hygienists that focuses on periodontal- and implant-related issues. Read more articles and subscribe to the newsletter.

References

1. Half of dentists say patients are high at dental appointments: marijuana use may affect oral health and treatment. American Dental Association. News release. November 3, 2022. https://www.ada.org/about/press-releases/half-of-dentists-say-patients-are-high-at-dental-appointments
2. Mechoulam R, Hanuš LO, Pertwee R, Howlett AC. Early phytocannabinoid chemistry to endocannabinoids and beyond. Nat Rev Neurosci.2014;15(11):757-764. doi:10.1038/nrn3811
3. Gangwani P, Lillian D, Dobbins J, Feng C, Vorrasi J, Kolokythas A. Is recreational marijuana use associated with changes in the vital signs or anesthetic requirements during intravenous sedation? J Oral Maxillofac Surg. 2023;81(5):527-535. doi:10.1016/j.joms.2023.01.007
4. Goudra B, Green M. Perioperative repercussions of cannabis use—implications for GI endoscopy sedation. J Clin Med. 2025;14(19):7028. doi:10.3390/jcm14197028
5. Hendrick L, Hendrick JR. Impact of cannabis use on the provision of dental care. Dimensions of Dental Hygiene. August 24, 2022. https://dimensionsofdentalhygiene.com/article/impact-cannabis-use-provision-dental-care/
6. Moran MC, Heaton LJ, Leroux BG, Flake NM. Local anesthetic efficacy in marijuana users and nonusers: a pilot study. Anesth Prog. 2022;69(4):15-21. doi:10.2344/anpr-69-02-08
7. Did you know that marijuana use can impact your surgery and post-surgery success? American College of Surgeons. https://www.facs.org/for-patients/preparing-for-surgery/marijuana-and-surgery/