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NCT Number: NCT03968822

Intralipid® 20% for Reversal of Local Anesthetics

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.

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This study is active but is not currently recruiting participants.

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Key information

Conditions

Anesthesia, Local

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Hospital of Special Surgery

New York, 10021, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Lidocaine 2%

Drug

3 mL of test solution to a skin area on the thigh, 2cm in diameter

Other names: Lidocaine Viscous, Lidoderm, Recticare

Lidocaine 1%

Drug

3 mL of test solution to a skin area on the thigh, 2cm in diameter

Other names: Lidocaine Viscous, Lidoderm, Recticare

Bupivacaine 0.25%

Drug

3 mL of test solution to a skin area on the thigh, 2cm in diameter

Other names: Marcaine, Sensorcaine

Bupivacaine 0.5%

Drug

3 mL of test solution to a skin area on the thigh, 2cm in diameter

Other names: Marcaine, Sensorcaine

Intralipid, 20% Intravenous

Drug

a 250ml bag administered intravenously

Other names: i.v. fat emulsion

Saline intravenously

Other

a 250ml bag administered intravenously

Other names: salt

Saline

Other

3 mL of test solution to a skin area on the thigh, 2cm in diameter

Other names: salt

Primary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. 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.

Secondary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

Sponsors and collaborators

Lead sponsor

Hospital for Special Surgery, New York

Other

Registry information

Official study title

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

Important dates

Study start
2019
Primary completion
2026
Study completion
2026
First posted
May 30, 2019
Registry last updated
Dec 8, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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