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Clinical Study to Evaluate the Effect of pH on Pain Upon Local Anesthetic Administration.

This study has been terminated.
(Insufficient Enrollment)
Information provided by (Responsible Party):
Brian Wainger, Massachusetts General Hospital Identifier:
First received: February 18, 2011
Last updated: February 28, 2017
Last verified: February 2017

When one receives a local anesthetic, such as novocaine for a dental procedure, there is a burning painful sensation experienced upon injection of the local anesthetic. We are trying to understand the role of pH (how acidic a solution is) in the production of pain during local anesthetic administration. We hypothesize that less acidic solutions produce less burning. We also want to determine whether or not the pH of the solution affects the rate of onset of the local anesthesia. We will recruit subjects from patients who have a clinical indication for lumbar medial branch (LMB) nerve blocks, procedures frequently performed at the Massachusetts General Hospital Center for Pain Medicine. For each patient, three nerve blocks are administered at adjacent spinal levels, typically using either lidocaine or bicarbonate-buffered lidocaine as the local anesthetic. We will add a saline control as part of the research procedure and then provide lidocaine at the control location before continuing with the nerve blocks. This clinical procedure offers an ideal opportunity to compare the effects of the three solutions. There will be almost no deviation from the standard clinical procedure. After the injection of each solution, the pain score on administration of the medication will be recorded immediately. We will also provide a continuous stimulation (pin taps) after the local anesthetic injection and record when the patient experiences hypoesthesia (reduced sensation) and anesthesia (absent sensation). Finally, we will record the pain score upon reinsertion of a needle to mark the precise location (part of the clinical procedure) one minute after the local anesthetic injection. All data will be collected during the a single clinical visit.

The study will conclude when 60 subjects have successfully been tested. Data will be reviewed annually.

Condition Intervention
Local Anesthetics
Drug: Lidocaine
Drug: normal saline
Drug: alkalinized lidocaine

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Participant, Care Provider
Primary Purpose: Basic Science
Official Title: A Single-center, Randomized, Double-blind Clinical Study to Evaluate the Effect of pH on Pain Upon Local Anesthetic Administration.

Resource links provided by NLM:

Further study details as provided by Massachusetts General Hospital:

Primary Outcome Measures:
  • Rank-transformed Pain Score [ Time Frame: immediate, upon injection of each solution ]

    Pain score upon injection of local anesthetic:

    the pain score is a validated 11-point numeric rating scale in which patients rate pain between 0 (no pain) and 10 (worst pain imaginable).

Secondary Outcome Measures:
  • Rank-transformed Time (Seconds) Until Hypoesthesia [ Time Frame: 0-180 seconds after each injection. ]
    Rank-transformed time (seconds) until hypoesthesia will be assessed using a sensory stimulus

  • Rank-transformed Time (Seconds) Until Anesthesia [ Time Frame: 0-180 seconds after each injection ]
    Rank-transformed time (seconds) until anesthesia will be assessed using a repeated sensory stimulus.

  • Rank-transformed Pain Score Upon Needle Stick. [ Time Frame: 1 minute after each injection ]

    Pain score upon needle stick:

    The pain score is a validated 11-point numeric rating scale in which patients rate pain between 0 (no pain) and 10 (worst pain imaginable).

Enrollment: 29
Study Start Date: January 2011
Study Completion Date: November 2014
Primary Completion Date: November 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: normal saline Drug: normal saline
1 ml subcutaneous injection 0.9% sodium chloride, given once
Active Comparator: lidocaine Drug: Lidocaine
1 ml subcutaneous injection of 0.9% lidocaine, given once
Experimental: alkalinized lidocaine Drug: alkalinized lidocaine
1 ml subcutaneous injection of 0.9% lidocaine and 0.84% sodium bicarbonate


Ages Eligible for Study:   19 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • patients at MGH Center for Pain Medicine who have clinical indication for undergoing diagnostic medial branch block of nerves to facet joints.

Exclusion Criteria:

  • contraindication to the clinical procedure
  • do not speak English
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Please refer to this study by its identifier: NCT01304082

United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Massachusetts General Hospital
Principal Investigator: Brian J Wainger, MD, PhD Massachusetts General Hospital
  More Information

Responsible Party: Brian Wainger, Instructor, Massachusetts General Hospital Identifier: NCT01304082     History of Changes
Other Study ID Numbers: 2010-P-000533
Study First Received: February 18, 2011
Results First Received: January 11, 2017
Last Updated: February 28, 2017

Keywords provided by Massachusetts General Hospital:
pain pH local anesthetics

Additional relevant MeSH terms:
Anesthetics, Local
Central Nervous System Depressants
Physiological Effects of Drugs
Sensory System Agents
Peripheral Nervous System Agents
Anti-Arrhythmia Agents
Voltage-Gated Sodium Channel Blockers
Sodium Channel Blockers
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action processed this record on April 28, 2017