Split Face Study of the Duration of Local Anesthetics - Fifth Arm

This study will compare the relative duration and efficacy of a commonly used local anesthetic (lidocaine with epinephrine) when administered into different layers of the skin on the ventral forearm within the same participant. Specifically, injections will be placed in the intradermal and subcutaneous tissue. A modification of a previously published noninvasive pinprick testing method will be used to assess the duration of local anesthesia. The investigators hypothesize that the duration of anesthesia will differ depending on the depth of injection, with intradermal and subcutaneous administration producing different durations of anesthetic effect.

This study record uses the same protocol document of a previous study under Clinical Trials record NCT06694714, but documents a fifth arm for which data will be analyzed separately from data in NCT06694714.

Inclusion criteria

• Male or female ≥ 18 years of age
• Normal skin sensation at both nasal ala and volar forearms assessed by pinprick
• Ability to provide informed consent

Exclusion criteria

• Previous adverse reaction to local anesthetic or any components of the local anesthetics being evaluated
• Pregnant or breastfeeding volunteers (assessed by self-report)
• Patients taking monoamineoxidase inhibitors (MAOI) or antidepressants of the triptyline or imipramine types