Effects of opioid tolerance on the duration of nerve blocks

Duration of Peripheral Nerve Blocks in Opioid Tolerant Individuals - A Volunteer Blinded Matched Case-control Study

Not applicable Interventional Regionshospitalet Silkeborg · NCT06488768

This study is testing how opioid tolerance affects the length of time a nerve block works in people who use opioids compared to those who don’t.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years to 84 Years
SexAll
SponsorRegionshospitalet Silkeborg Academic / other
Locations1 site (Silkeborg)
Trial IDNCT06488768 on ClinicalTrials.gov

What this trial studies

This study investigates how opioid tolerance affects the effectiveness of peripheral nerve blocks, specifically focusing on the radial nerve block. It compares the onset time and duration of sensory and motor blockade in opioid-tolerant individuals to those who are opioid-naive. The study involves matching twenty opioid-tolerant participants with opioid-naive counterparts based on age and sex, and utilizes ultrasound guidance for the nerve block procedure. The primary outcome is to determine the differences in the duration of the nerve block between the two groups.

Who should consider this trial

Good fit: Ideal candidates include adults over 18 years old who are either opioid-tolerant with chronic pain or opioid-naive individuals.

Not a fit: Patients who are not opioid-tolerant or those with conditions that exclude them from the study criteria may not benefit.

Why it matters

Potential benefit: If successful, this study could lead to improved pain management strategies for patients with opioid tolerance.

How similar studies have performed: While there is existing research on opioid tolerance affecting analgesia, this specific investigation into peripheral nerve blocks is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion criteria for opioid group

* 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

Inclusion criteria for the opioid naive control group

* Age \> 18 years old
* ASA 1-3
* No use of opioids within 30 days prior to participation
* Legally competent and able to give informed consent

Exclusion Criteria:

* 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
* 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.

Where this trial is running

Silkeborg

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Nerve BlockOpioid ToleranceOpioid toleranceRadialis Nerve block
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.