Intralipid® 20% for Reversal of Local Anesthetics

December 2, 2025 updated by: Hospital for Special Surgery, New York

The Use of Intralipid® 20% Solution to Reverse the Anesthetic Effect of Local Anesthetics: a Proof of Concept Study in Volunteers

In order to determine if Intralipid 20% can be used to reverse the effects of local anesthetics, the investigators will recruit 18 volunteers who will be asked to come to HSS for two study visits. Small amounts of local anesthetics will be injected into the volunteers' thighs during both visits. During one visit volunteers will receive Intralipid 20% and during the other visit they will receive a saline solution. The study team will measure how quickly normal sensation returns to the thighs when the volunteers get Intralipid 20% compared to saline.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The purpose of this study is to determine if a fat solution (Intralipid 20%) given intravenously can reverse the effects of local anesthetics. Local anesthetics are drugs that cause numbness when they are injected into different parts of the body. Local anesthetics are important drugs because they allow doctors to perform surgeries and other procedures on patients; however, there are certain instances where it would be helpful to reverse the effects of local anesthetics and reduce the amount of time that they produce numbness. In order to determine if Intralipid 20% can be used to reverse the effects of local anesthetics, the investigators will recruit 18 volunteers who will be asked to come to HSS for two study visits. Small amounts of local anesthetics will be injected into the volunteers' thighs during both visits. During one visit volunteers will receive Intralipid 20% and during the other visit they will receive a saline solution. The study team will measure how quickly normal sensation returns to the thighs when the volunteers get Intralipid 20% compared to saline.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
18

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • New York
      • New York, New York, United States, 10021
        • Hospital of Special Surgery

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • English speaking
  • BMI 18-25, with body weight between 50-100kg

Exclusion Criteria:

  • ASA III or higher
  • Pregnant Women
  • Allergy to study medications (lidocaine, bupivacaine, soybeans, eggs)
  • Use of drugs affecting the sensorium (including opioids, benzodiazepines, antipsychotics, gabapentinoids)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Intralipid 20% IV Bolus

This is 1 out of the 2 study visits. The patient will receive 6 injections (3 in each thigh). The 6 injections are:

  1. lidocaine 1%
  2. lidocaine 2%
  3. bupivacaine 0.5%
  4. bupivacaine 0.25%
  5. saline
  6. no injection

Each test solution will be injected over 5 seconds through a 27G needle and tuberculin syringe at a 30 degree angle.

The patient will also receive an intravenous bolus in the arm of Intralipid 20%.

Participant will be blindfolded for these activities so they will not know what they received during the visit.
Drug: Lidocaine 2%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Lidoderm
  • Lidocaine Viscous
  • Recticare
Drug: Lidocaine 1%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Lidoderm
  • Lidocaine Viscous
  • Recticare
Drug: Bupivacaine 0.25%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Marcaine
  • Sensorcaine
Drug: Bupivacaine 0.5%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Marcaine
  • Sensorcaine
Drug: Intralipid, 20% Intravenous
a 250ml bag administered intravenously
Other Names:
  • i.v. fat emulsion
Other: Saline
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • salt
Placebo Comparator: Saline

This is 2 out of the 2 study visits. The patient will receive 6 injections (3 in each thigh). The 6 injections are:

  1. lidocaine 1%
  2. lidocaine 2%
  3. bupivacaine 0.5%
  4. bupivacaine 0.25%
  5. saline
  6. no injection

Each test solution will be injected over 5 seconds through a 27G needle and tuberculin syringe at a 30 degree angle.

The patient will also receive an intravenous bolus in the arm of Saline.

Participant will be blindfolded for these activities so they will not know what they received during the visit.
Drug: Lidocaine 2%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Lidoderm
  • Lidocaine Viscous
  • Recticare
Drug: Lidocaine 1%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Lidoderm
  • Lidocaine Viscous
  • Recticare
Drug: Bupivacaine 0.25%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Marcaine
  • Sensorcaine
Drug: Bupivacaine 0.5%
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • Marcaine
  • Sensorcaine
Other: Saline
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Other Names:
  • salt
Other: Saline intravenously
a 250ml bag administered intravenously
Other Names:
  • salt

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Time to complete normal sensation after lidocaine 1%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of both cold swab and pinprick at the injection site of lidocaine 1%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to complete normal sensation after lidocaine 2%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of both cold swab and pinprick at the injection site of lidocaine 2%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to complete normal sensation after Bupivacaine 0.5%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of both cold swab and pinprick at the injection site of Bupivacaine 0.5%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to complete normal sensation after Bupivacaine 0.25%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of both cold swab and pinprick at the injection site of Bupivacaine 0.25%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Time to normal cold swab sensation after lidocaine 1%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of cold swab at the injection site of lidocaine 1%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to normal pinprick sensation after lidocaine 1%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of pinprick at the injection site of lidocaine 1%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to normal cold swab sensation after lidocaine 2%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of cold swab at the injection site of lidocaine 2%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to normal pin prick sensation after lidocaine 2%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of pinprick at the injection site of lidocaine 2%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to normal pinprick sensation after Bupivacaine 0.5%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of pinprick at the injection site of Bupivacaine 0.5%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to normal cold swab sensation after Bupivacaine 0.5%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of cold swab at the injection site of Bupivacaine 0.5%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to normal cold swab sensation after Bupivacaine 0.25%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of cold swab at the injection site of Bupivacaine 0.25%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours
Time to normal pinprick sensation after Bupivacaine 0.25%
Time Frame: up to 24 hours

The time (measured in minutes) when the participant reports normal sensation of pinprick at the injection site of Bupivacaine 0.25%.

Although measured for each individual participant, the average time across all participants is reported.
up to 24 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Hospital for Special Surgery, New York

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Stavros Memtsoudis, MD/PhD, Hospital for Special Surgery, New York

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 26, 2019

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 21, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 28, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 30, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 8, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 2, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2018-2039

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures)

IPD Sharing Time Frame

Beginning 9 months and ending 36 months following article publication

IPD Sharing Access Criteria

Investigators whose proposed use of the data has been approved by an independent review committee identified for this purpose. For individual participant meta-analysis. Proposals may be submitted up to 36 months following article publication. After 36 months the data will be available in our data warehouse but without investigator support other than deposited metadata.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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