Validating a New Non-invasive Approach to Testing Lidocaine Effectiveness
Condition: ADHD; Controls
Study type: Interventional
Phase: Early Phase 1

Summary: 
      This work will assess the reliability of a simple painless test for the effectiveness of the
      commonly used local anesthetic lidocaine
    

Detailed description: 
      In prior tests with a convenience sample, subjects who reported that they had no trouble
      getting numb at the dentist, also got numb with lidocaine gel on the surface of the tongue.
      That numbness prevented them from being able to taste any flavor until the numbness had worn
      off. Subjects who reported having trouble getting numb at the dentist, could still taste
      flavors after the application of lidocaine.

      This work will assess the reliability of a taste-based approach for creating a non-invasive
      way to test lidocaine effectiveness. The controlled trial will assess the ability of
      lidocaine oral gel to block taste (e.g., sweet) in 20 adults (ages 18-49) half with history
      of trouble getting numb at the dentist (Arm 2) and half with no trouble (Arm 1). To determine
      reproducibility, the taste-based test will be done 4 times on different days, twice with
      lidocaine and twice with a placebo, with randomization and double-blinding. These repeated
      results will be compared to a fifth assessment, against the "gold standard" of injection of
      lidocaine, assessed using a dental probe.

      On each of four separate visits, in randomized order, the subject will be tested with
      tastants to the tongue twice after application of a lidocaine gel to the tongue and twice
      with a placebo gel. After a wait of two-minutes, the three tastants will be tested. The
      subject is blinded to the taste and the identity of the gel, which have been compounded to
      look the same.

      On the fifth (last) visit, the subject will get an oral injection of lidocaine and the
      numbness assessed.

      The results across the five tests will then be analyzed.

      We are testing in separate studies NCT 03563573 and NCT 03676725 the prevalence of lidocaine
      ineffectiveness in those with Attention Deficit Hyperactivity Disorder (ADHD) and in the
      general population without ADHD. We believe the prevalence will be higher in ADHD. As a
      result, in this evaluation we have one Arm "gets numb at the dentist" where exclusion
      criteria includes ADHD and a second Arm "has trouble getting numb at the dentist" that does
      not have that exclusion.
    

Intervention name(s): Lidocaine gel; Placebo; Injected lidocaine
Intervention type(s): Drug; Drug; Drug
Intervention description(s): Lidocaine gel 5%, PEG with FD&C Blue No.1 (Brilliant Blue FCF); PEG with FD&C Blue No.1 (Brilliant Blue FCF); Standard FDA-approved dental injectable lidocaine
Other intervention name(s): Intervention; Control gel; Current practice
Intervention MeSH terms: Lidocaine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Half the subjects will have a self-reported history of lidocaine working for them (effective) and half will have a history of difficulty getting numb (ineffective).
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Health Services Research
Keywords: Lidocaine ineffectiveness; ADHD; ADD