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NCT Number: NCT01992146

Effect of High-dose Naloxone Infusion on Pain and Hyperalgesia in Patients Following Groin-Hernia Repair.

Recent studies have focused on the role of endogenous opioids on central sensitization. Central sensitization is known to be impaired or altered in chronic pain conditions, as fibromyalgia or chronic tension headache.

Animal studies have shown reinstatement of mechanical hypersensitivity following naloxone administration after resolution of an injury. This suggests latent sensitization.

In the present study, investigators hypothesize that a high-dose target-controlled naloxone infusion (total dose: 3.25 mg/kg) can reinstate pain and hyperalgesia 6-8 weeks after a unilateral primary open groin hernia repair procedure. Investigators aim to show that latent sensitization is present in humans and is modulated by endogenous opioids.

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Key information

Conditions

Central Nervous System Sensitization Hyperalgesia Nervous System Diseases Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Sensation Disorders Signs and Symptoms Somatosensory Disorders

Age range

18 year–65 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 2

Primary location

Multidisciplinary Pain Center, 7612, HOC, Rigshospitalet

Copenhagen, 2100, Denmark

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Age ≥ 18 years and ≤ 65 years
  • Signed informed consent
  • Patients submitted to unilateral, primary inguinal, open herniotomy 6-8 weeks prior to study start.
  • Open operating procedure a.m. Lichtenstein.
  • Urin sample without traces of opioids (morphine, methadon, buprenorphine, codeine, tramadol, ketobemidone, oxycodone, hydromorphine, dextromethorphan)
  • ASA I-II
  • Body mass index (BMI): 18 < BMI < 30

Exclusion criteria

  • Volunteers , who do not speak or understand Danish
  • Patients, who cannot cooperate with the investigation
  • Patients who have had previous surgery in the groin region
  • Patients with pain at rest > 3 (NRS)
  • Activity-related pain in the surgical field > 5
  • Allergic reaction against morphine or other opioids (including naloxone),
  • Abuse of alcohol or drugs - according to investigator's evaluation
  • Use of psychotropic drugs (exception of SSRI)
  • Neurologic or psychiatric disease
  • Chronic pain condition
  • Regular use of analgesic drugs
  • Skin lesions and tattoos in the assessment areas
  • Nerve lesions in the assessment sites (for instance, after trauma, disc herniation, etc.)
  • Use of prescription drugs 1 week before the trial
  • Use of over-the-counter drugs 48 hours before the trial

Treatment and study plan

Target-controlled naloxone-infusion

Drug

Placebo

Drug

Primary outcomes

  1. Summated pain intensity

    Time frame: 1st session: 6-8 weeks after surgery; 2nd session: one week later

    Change in pain ratings ([NRS,0-10] pain at rest + pain during transition from supine to standing position + pain during pressure (100 kPa) at injury site), assessed 6-8 weeks after unilateral, primary, open groin hernia repair following administration of naloxone/placebo.

Secondary outcomes

  1. Secondary hyperalgesia/allodynia

    Time frame: 1st session: 6-8 weeks after surgery; 2nd session: one week later

    Change in secondary hyperalgesia area/allodynia at surgical site and at the mirror-site in the contralateral groin assessed 6-8 weeks after unilateral, primary, open groin hernia repair following administration of naloxone/placebo.

  2. Pressure pain thresholds

    Time frame: 1st session: 6-8 weeks; 2nd session: one week later

    Change in pressure pain thresholds at surgical site and at the mirror-site in the contralateral groin assessed 6-8 weeks after unilateral, primary, open groin hernia repair following administration of naloxone/placebo.

Other outcomes

  1. Pain Catastrophizing Scale

    Time frame: in the 1st session: 6-8 weeks after surgery

    Patients fill out Pain Catastrophizing Scale before assessments on the first study day

  2. Hospital Anxiety and Depression Scale

    Time frame: in the 1st session: 6-8 weeks after surgery

    Patients fill out Hospital Anxiety and Depression Scale before assessments on the first study day

  3. Clinical Opiate Withdrawal Scale

    Time frame: 1st session: 6-8 weeks after surgery; 2nd session: one week later

    Clinical Opiate Withdrawal Scale is filled out before and during naloxone/placebo administration in each experimental session

Sponsors and collaborators

Lead sponsor

Rigshospitalet, Denmark

Other

Collaborators

  • National Institute on Drug Abuse (NIDA)
  • University of Kentucky

Registry information

Official study title

Effect of High-dose Naloxone Infusion on Pain and Hyperalgesia in Patients Following Groin-Hernia Repair. A Randomized, Placebo-controlled, Double-blind Crossover Study

Important dates

Study start
2015
Primary completion
2015
Study completion
2018
First posted
Nov 25, 2013
Registry last updated
Feb 22, 2024

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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