Anesthesia, LocalPhase 4NCT03968822
Intralipid® 20% for Reversal of Local Anesthetics
A Phase 4 study testing Lidocaine 2%, Lidocaine 1% and Bupivacaine 0.25% in people with Anesthesia, Local, run by Hospital for Special Surgery, New York at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Anesthesia, Local
- What is being tested?
- Lidocaine 2%, Lidocaine 1% and Bupivacaine 0.25%
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 18 participants
- Where
- 1 siteUnited States
- Study dates
- 26 Jul 2019to Oct 2026
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- English speaking
- BMI 18-25, with body weight between 50-100kg
Who cannot join
- 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)
Trial locations and contacts
1 site in 1 country.
United States1 site
Hospital of Special Surgery
New York, New York, 10021
About this study
Official title: 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.
Read the 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.
- Conditions
- Anesthesia, Local
- Being tested
- Lidocaine 2%, Lidocaine 1%, Bupivacaine 0.25%, Bupivacaine 0.5%, Intralipid, 20% Intravenous
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Lidocaine 2%Drug
Also called Lidocaine Viscous, Lidoderm, Recticare
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Lidocaine 1%Drug
Also called Lidocaine Viscous, Lidoderm, Recticare
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Bupivacaine 0.25%Drug
Also called Marcaine, Sensorcaine
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Bupivacaine 0.5%Drug
Also called Marcaine, Sensorcaine
3 mL of test solution to a skin area on the thigh, 2cm in diameter
Intralipid, 20% IntravenousDrug
Also called i.v. fat emulsion
a 250ml bag administered intravenously
Saline intravenouslyOther
Also called salt
a 250ml bag administered intravenously
SalineOther
Also called salt
3 mL of test solution to a skin area on the thigh, 2cm in diameter
| Study group | Role | What they receive |
|---|---|---|
| Intralipid 20% IV Bolus | Experimental | 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. Receives: Drug: Lidocaine 2%; Drug: Lidocaine 1%; Drug: Bupivacaine 0.25%; Drug: Bupivacaine 0.5%; Drug: Intralipid, 20% Intravenous; Other: Saline |
| Saline | Placebo comparator | 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. Receives: Drug: Lidocaine 2%; Drug: Lidocaine 1%; Drug: Bupivacaine 0.25%; Drug: Bupivacaine 0.5%; Other: Saline intravenously; Other: Saline |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to complete normal sensation after lidocaine 1%
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.
Measured: up to 24 hours
Time to complete normal sensation after lidocaine 2%
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.
Measured: up to 24 hours
Time to complete normal sensation after Bupivacaine 0.5%
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.
Measured: up to 24 hours
Time to complete normal sensation after Bupivacaine 0.25%
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.
Measured: up to 24 hours
Secondary outcomes (8)
Time to normal cold swab sensation after lidocaine 1%
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.
Measured: up to 24 hours
Time to normal pinprick sensation after lidocaine 1%
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.
Measured: up to 24 hours
Time to normal cold swab sensation after lidocaine 2%
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.
Measured: up to 24 hours
Time to normal pin prick sensation after lidocaine 2%
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.
Measured: up to 24 hours
Time to normal pinprick sensation after Bupivacaine 0.5%
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.
Measured: up to 24 hours
Time to normal cold swab sensation after Bupivacaine 0.5%
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.
Measured: up to 24 hours
Time to normal cold swab sensation after Bupivacaine 0.25%
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.
Measured: up to 24 hours
Time to normal pinprick sensation after Bupivacaine 0.25%
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.
Measured: up to 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 May 2019
- Study start26 Jul 2019
- Primary completionOct 2026 (estimated)
- Study completionOct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Anesthesia, LocalStudies of the same condition, open and under way.
- More trials run by Hospital for Special Surgery, New YorkThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 18 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospital for Special Surgery, New York
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Stavros Memtsoudis, MD/PhD, Principal investigator, Hospital for Special Surgery, New York
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03968822
- Sponsor's protocol ID
- 2018-2039
- Status last verified
- Dec 2025
- First submitted
- 21 May 2019
- Last updated
- 8 Dec 2025
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures)
Study at a glance
From the registry record, last updated by the sponsor on 8 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Use of Intralipid® 20% Solution to Reverse the Anesthetic Effect of Local Anesthetics: a Proof of Concept Study in Volunteers
- ClinicalTrials.gov ID
- NCT03968822
- Acronym / sponsor ID
- 2018-2039
- Conditions
- Anesthesia, Local
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 18 participants (estimated)
- Lead sponsor
- Hospital for Special Surgery, New YorkUniversity, hospital or other
- Study start
- 26 Jul 2019 (actual)
- Primary completion
- Oct 2026 (estimated)
- Study completion
- Oct 2026 (estimated)
- First posted
- 30 May 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Intralipid 20% IV Bolus | Experimental | Drug: Lidocaine 2%, Drug: Lidocaine 1%, Drug: Bupivacaine 0.25%, Drug: Bupivacaine 0.5%, Drug: Intralipid, 20% Intravenous, Other: SalineThis 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. |
| Saline | Placebo comparator | Drug: Lidocaine 2%, Drug: Lidocaine 1%, Drug: Bupivacaine 0.25%, Drug: Bupivacaine 0.5%, Other: Saline intravenously, Other: SalineThis 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- English speaking
- BMI 18-25, with body weight between 50-100kg
Key exclusion criteria (4 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Lidocaine 2%Also: Lidocaine Viscous, Lidoderm, Recticare3 mL of test solution to a skin area on the thigh, 2cm in diameter | Drug | Intralipid 20% IV Bolus, Saline |
| Lidocaine 1%Also: Lidocaine Viscous, Lidoderm, Recticare3 mL of test solution to a skin area on the thigh, 2cm in diameter | Drug | Intralipid 20% IV Bolus, Saline |
| Bupivacaine 0.25%Also: Marcaine, Sensorcaine3 mL of test solution to a skin area on the thigh, 2cm in diameter | Drug | Intralipid 20% IV Bolus, Saline |
| Bupivacaine 0.5%Also: Marcaine, Sensorcaine3 mL of test solution to a skin area on the thigh, 2cm in diameter | Drug | Intralipid 20% IV Bolus, Saline |
| Intralipid, 20% IntravenousAlso: i.v. fat emulsiona 250ml bag administered intravenously | Drug | Intralipid 20% IV Bolus |
| Saline intravenouslyAlso: salta 250ml bag administered intravenously | Other | Saline |
| SalineAlso: salt3 mL of test solution to a skin area on the thigh, 2cm in diameter | Other | Intralipid 20% IV Bolus, Saline |
Primary outcome
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.
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.
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.
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.
8 secondary outcomes
Time to normal cold swab sensation after lidocaine 1%
Time frame: up to 24 hours
Time to normal pinprick sensation after lidocaine 1%
Time frame: up to 24 hours
Time to normal cold swab sensation after lidocaine 2%
Time frame: up to 24 hours
Time to normal pin prick sensation after lidocaine 2%
Time frame: up to 24 hours
Time to normal pinprick sensation after Bupivacaine 0.5%
Time frame: up to 24 hours
Time to normal cold swab sensation after Bupivacaine 0.5%
Time frame: up to 24 hours
Time to normal cold swab sensation after Bupivacaine 0.25%
Time frame: up to 24 hours
Time to normal pinprick sensation after Bupivacaine 0.25%
Time frame: up to 24 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Dec 2025.
- Individual participant dataSharing planned: Yes. Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures)
Related trials for Anesthesia, Local
RecruitingPhase 4
Lidocaine Infiltration and Neuroimmunomodulation in Head and Neck Cancer Surgery
Head and Neck Cancer (H&N)
Recruiting
Minimum Effective Local Anesthetic Volume for Ultrasound Guided Superior Trunk Block
Musculoskeletal Diseases or Conditions
RecruitingPhase 3
A Study of Changes to Prostate Procedures
Prostate Cancer
Not yet recruiting
Magnesium Sulphate as an Adjuvant in Combined Costoclavicular Block and Suprascapular Block Versus Interscalene Block for Ambulatory Shoulder Arthroscopy
Postoperative Pain, Shoulder Arthroscopy
Recruiting
Comparison of Spinal Anesthesia With Intrathecal Morphine Versus PENG Block With or Without Dexamethasone in Hip Arthroplasty
Arthropathy of Hip, Hip Osteoarthritis
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Stavros Memtsoudis, MD/PhD principal investigator
Hospital for Special Surgery, New York
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Lidocaine 2%, Lidocaine 1% and Bupivacaine 0.25% in people with Anesthesia, Local, run by Hospital for Special Surgery, New York at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 8 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to complete normal sensation after lidocaine 1% (time frame: up to 24 hours). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Dec 2025.