Nerve BlockOPITOBLOKNCT06488768
Duration of Peripheral Nerve Blocks in Opioid Tolerant Individuals - A Volunteer Blinded Matched Case-control Study
A study testing Radial nerve block in people with Nerve Block and Opioid Tolerance, run by Charlotte Runge at 1 site in Denmark.
Trial summary
Do peripheral nerve blocks work shorter if you are on opioids? Background: Peripheral nerve blocks effectively alleviate postoperative pain. Animal studies and human research indicate that opioid tolerance results in reduced effectiveness of local analgesics. Read more about this study
- Who is it for?
- Ages 18 to 84 yearsHealthy volunteers can take part
- Conditions the study is for
- Nerve Block, Opioid Tolerance
- What is being tested?
- Radial nerve block
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteDenmark
- Study dates
- 17 Jun 2024to 16 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 to 84 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age > 18 years old
- ASA 1-3
- Chronic pain, defined as persisting pain for more than three months
- Daily use of more than 60 mg of morphine equivalent in more than 7 days
- Legally competent and able to give informed consent
- Age > 18 years old
Show all 9Show fewer
- ASA 1-3
- No use of opioids within 30 days prior to participation
- Legally competent and able to give informed consent
Who cannot join
- Age > 84 years old
- Volunteers who cannot cooperate with the study
- Volunteers who cannot understand or speak Danish
- Allergy to the lidocaine or the preservatives used in the study
- Alcohol or drug abuse other than opioids
- Peripheral neuropathy at the upper limb non-dominant arm
Show all 14Show fewer
- Pathology or previous major surgery to the upper limb
- Active signs of infection in the cutaneous area of injection
- Pregnancy at the time of the trial
- Partial or complete 2nd or 3rd degree atrioventricular heart block without a pacemaker
- Severe liver disease
- Severe kidney disease and reduced kidney function (eGFR below 30 mL/min)
- Daily treatment with drugs that are structurally related to local analgesics or class IB antiarrhythmics, as the toxic effects are additive
- Daily treatment with class III antiarrhythmics e.g., amiodarone.
Trial locations and contacts
1 site in 1 country.
About this study
Do peripheral nerve blocks work shorter if you are on opioids?
Background:
Read more
Peripheral nerve blocks effectively alleviate postoperative pain. Animal studies and human research indicate that opioid tolerance results in reduced effectiveness of local analgesics. This applies to both central nerve blockade and infiltration anaesthesia. The impact on peripheral nerve block in humans has not been evaluated. The aim of the study is to assess the onset time and duration of a radial nerve block in opioid tolerant individuals compared to opioid naive individuals. We hypothesise that peripheral nerve blocks cause shorter sensory and motor block in opioid-tolerant compared to opioid-naive counterparts.
Methods:
Twenty opioid-tolerant individuals will be matched by sex and age with opioid-naïve counterparts. Participants will undergo an ultrasound-guided radial nerve block. The onset time and duration of motor and sensory blockade will be tested and measured. The primary outcome is difference in duration of sensory nerve blockade between the two groups. The secondary outcomes include the onset time of sensory blockade, onset time of motor blockade, and difference in duration of motor nerve blockade.
Perspectives:
The data from this study will provide evidence for the duration of peripheral nerve block in opioid tolerant individuals and support if a specific postoperative protocol for opioid tolerant individuals is needed or it should be of special attention.
- Conditions
- Nerve Block, Opioid Tolerance
- Being tested
- Radial nerve block
- Keywords
- Nerve Block, Opioid tolerance, Radialis Nerve block
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Radial nerve blockOther
Ultrasound-guided Radial nerve block. Conducted with 10 mL of Lidocaine 2%. Ultrasound image are stored for documentation.
| Study group | Role | What they receive |
|---|---|---|
| Opioid tolerant | Experimental | Daily use of opioid of 60 mg or more Receives: Other: Radial nerve block |
| Opioid naive | Experimental | No use of opioids within the last 30 days Receives: Other: Radial nerve block |
What is being measured
The primary outcome is the main question the study is designed to answer.
The difference in the duration of sensory block for a radial nerve block between opioid-tolerant and opioid-naive individuals.
Following the injection of local anaesthetic, motor and sensory assessments will be conducted at 30-second intervals until complete sensory and motor blockade, respectively. These assessments will involve comparisons with the contralateral side.
Sensory testing will be performed on the dorsal side of the 1. intermetacarpal area (the space between the thumb and the index finger) and the proximal dorsolateral area of the antebrachium. In both areas seeking to explore the boundaries of the innervation area.
Dual testing is performed to accommodate interindividual variabilities in dermatomes. Sensation will be evaluated with a monofilament (Touch Test, 60 g; Stoelting, Co, Wood Dale, IL) using a 11-point sensory scale:
5 = extremely intense sensation 0 = normal sensation.
-5 = no sensation.
Measured: Up to one hour after nerve block placement.
Secondary outcomes (3)
The difference in the onset time of sensory block from a radial nerve block between opioid-tolerant and opioid-naive individuals.
Following the injection of local anaesthetic, motor and sensory assessments will be conducted at 30-second intervals until complete sensory and motor blockade, respectively. These assessments will involve comparisons with the contralateral side.
Sensory testing will be performed on the dorsal side of the 1. intermetacarpal area (the space between the thumb and the index finger) and the proximal dorsolateral area of the antebrachium. In both areas seeking to explore the boundaries of the innervation area.
Dual testing is performed to accommodate interindividual variabilities in dermatomes. Sensation will be evaluated with a monofilament (Touch Test, 60 g; Stoelting, Co, Wood Dale, IL) using a 11-point sensory scale:
5 = extremely intense sensation 0 = normal sensation.
-5 = no sensation.
Measured: Up to one hour after nerve block placement.
The difference in the onset time of motor block from a radial nerve block between opioid-tolerant and opioid-naive individuals.
Following the injection of local anaesthetic, motor and sensory assessments will be conducted at 30-second intervals until complete sensory and motor blockade, respectively. These assessments will involve comparisons with the contralateral side.
With the arm placed in pronated position on a flat and solid surface the ability to dorsally flex the wrist is used to evaluate motor block on a Modified Bromage three-point scale: 0 = normal contraction.
- 1 = reduced contraction.
- 2 = no contraction.
Measured: Up to one hour after nerve block placement.
The difference in the duration of motor block for a radial nerve block between opioid-tolerant and opioid-naive individuals.
Following the injection of local anaesthetic, motor and sensory assessments will be conducted at 30-second intervals until complete sensory and motor blockade, respectively. These assessments will involve comparisons with the contralateral side.
With the arm placed in pronated position on a flat and solid surface the ability to dorsally flex the wrist is used to evaluate motor block on a Modified Bromage three-point scale: 0 = normal contraction.
- 1 = reduced contraction.
- 2 = no contraction.
Measured: Up to one hour after nerve block placement.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jul 2024
- Study start17 Jun 2024
- Primary completion16 Dec 2025
- Study completion16 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Nerve BlockStudies of the same condition, open and under way.
- 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 N/A
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- A volunteer blinded matched case-control study.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- Charlotte Runge
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Charlotte Runge, Regionshospitalet Silkeborg
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06488768
- Sponsor's protocol ID
- 2023-509351-13-00
- Other IDs
- 2023
- Acronym
- OPITOBLOK
- Status last verified
- Aug 2026
- First submitted
- 17 Jun 2024
- Last updated
- 14 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: all IPD that underlie results in a publication
Study at a glance
From the registry record, last updated by the sponsor on 14 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Duration of Peripheral Nerve Blocks in Opioid Tolerant Individuals - A Volunteer Blinded Matched Case-control Study
- ClinicalTrials.gov ID
- NCT06488768
- Acronym / sponsor ID
- OPITOBLOK / 2023-509351-13-00
- Conditions
- Nerve Block, Opioid Tolerance
- Keywords
- Nerve Block, Opioid tolerance, Radialis Nerve block
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- Charlotte RungeUniversity, hospital or other
- Study start
- 17 Jun 2024 (actual)
- Primary completion
- 16 Dec 2025 (actual)
- Study completion
- 16 Dec 2025 (actual)
- First posted
- 5 Jul 2024 (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.
Do peripheral nerve blocks work shorter if you are on opioids?
Background:
Peripheral nerve blocks effectively alleviate postoperative pain. Animal studies and human research indicate that opioid tolerance results in reduced effectiveness of local analgesics. This applies to both central nerve blockade and infiltration anaesthesia. The impact on peripheral nerve block in humans has not been evaluated. The aim of the study is to assess the onset time and duration of a radial nerve block in opioid tolerant individuals compared to opioid naive individuals. We hypothesise that peripheral nerve blocks cause shorter sensory and motor block in opioid-tolerant compared to opioid-naive counterparts.
Methods:
Twenty opioid-tolerant individuals will be matched by sex and age with opioid-naïve counterparts. Participants will undergo an ultrasound-guided radial nerve block. The onset time and duration of motor and sensory blockade will be tested and measured. The primary outcome is difference in duration of sensory nerve blockade between the two groups. The secondary outcomes include the onset time of sensory blockade, onset time of motor blockade, and difference in duration of motor nerve blockade.
Perspectives:
The data from this study will provide evidence for the duration of peripheral nerve block in opioid tolerant individuals and support if a specific postoperative protocol for opioid tolerant individuals is needed or it should be of special attention.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- A volunteer blinded matched case-control study.
| Arm | Type | Receives |
|---|---|---|
| Opioid tolerant | Experimental | Other: Radial nerve blockDaily use of opioid of 60 mg or more |
| Opioid naive | Experimental | Other: Radial nerve blockNo use of opioids within the last 30 days |
Who may qualify
- Ages
- 18 to 84 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- Age > 18 years old
- ASA 1-3
- Chronic pain, defined as persisting pain for more than three months
- Daily use of more than 60 mg of morphine equivalent in more than 7 days
- Legally competent and able to give informed consent
Key exclusion criteria (14 listed)
- Age > 84 years old
- Volunteers who cannot cooperate with the study
- Volunteers who cannot understand or speak Danish
- Allergy to the lidocaine or the preservatives used in the study
- Alcohol or drug abuse other than opioids
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 |
|---|---|---|
| Radial nerve blockUltrasound-guided Radial nerve block. Conducted with 10 mL of Lidocaine 2%. Ultrasound image are stored for documentation. | Other | Opioid naive, Opioid tolerant |
Primary outcome
The difference in the duration of sensory block for a radial nerve block between opioid-tolerant and opioid-naive individuals.
Time frame: Up to one hour after nerve block placement.
Following the injection of local anaesthetic, motor and sensory assessments will be conducted at 30-second intervals until complete sensory and motor blockade, respectively. These assessments will involve comparisons with the contralateral side. Sensory testing will be performed on the dorsal side of the 1. intermetacarpal area (the space between the thumb and the index finger) and the proximal dorsolateral area of the antebrachium. In both areas seeking to explore the boundaries of the innervation area. Dual testing is performed to accommodate interindividual variabilities in dermatomes. Sensation will be evaluated with a monofilament (Touch Test, 60 g; Stoelting, Co, Wood Dale, IL) using a 11-point sensory scale: 5 = extremely intense sensation 0 = normal sensation. -5 = no sensation.
3 secondary outcomes
The difference in the onset time of sensory block from a radial nerve block between opioid-tolerant and opioid-naive individuals.
Time frame: Up to one hour after nerve block placement.
The difference in the onset time of motor block from a radial nerve block between opioid-tolerant and opioid-naive individuals.
Time frame: Up to one hour after nerve block placement.
The difference in the duration of motor block for a radial nerve block between opioid-tolerant and opioid-naive individuals.
Time frame: Up to one hour after nerve block placement.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Aug 2026.
- Individual participant dataSharing planned: Yes. all IPD that underlie results in a publication
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Radial nerve block in people with Nerve Block and Opioid Tolerance, run by Charlotte Runge at 1 site in Denmark.
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 9 inclusion and 14 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: finished, as of the sponsor's last update on 14 Aug 2026. 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 Denmark. 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
The difference in the duration of sensory block for a radial nerve block between opioid-tolerant and opioid-naive individuals. (time frame: Up to one hour after nerve block placement.). 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 14 Aug 2026.