Local Anesthetic Efficacy in Marijuana Users and Nonusers: A Pilot Study.

Objective: Despite the common clinical impression that patients with a history of drug use are challenging to anesthetize with local anesthesia, literature on this clinical phenomenon is sparse. The objective of this pilot study was to assess if differences in local anesthetic efficacy for dental treatment exist between marijuana users and nonusers.

Methods: Subjects were healthy adult males and females who qualified as either chronic marijuana users or nonusers. All subjects had an asymptomatic, vital maxillary lateral incisor that responded to an electric pulp test (EPT). A standard maxillary infiltration injection technique was employed using 1.7 mL 2% lidocaine with 1:100,000 epinephrine over the test tooth, and the tooth was tested with an EPT at 3-minute intervals.

Results: A total of 88% of nonusers (15/17) and 61% of users (11/18) were successfully anesthetized, defined as anesthesia onset within 10 minutes and lasting at least 15 minutes. The difference in the proportion of anesthetized subjects was not statistically significant (P = .073). For subjects with successful anesthesia, there was no significant difference between nonusers and users in the onset or duration of anesthesia.

Conclusion: No significant differences in local anesthetic efficacy with respect to local anesthetic success, onset, or duration of action were found between chronic marijuana users and nonusers. However, larger studies are likely needed to provide more definitive evidence.