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RecruitingNCT02502162LDN-CRPSUpdated May 29, 2025

Low-Dose Naltrexone for the Treatment of Complex Regional Pain Syndrome

An interventional study of LDN and Placebo in Complex Regional Pain Syndrome, sponsored by Stanford University. Recruiting at 1 site in United States. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2025-05-29.

Sponsored by Stanford University · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
120
Allocation
Randomized
Ages
18 Years to 70 Years
Sex
All
01

Study summary

The investigators are testing treatment with low-dose naltrexone (LDN) for symptom relief of complex regional pain syndrome (CRPS). Study participants will be randomly assigned to receive either LDN or placebo for a period of several weeks. During this period participants will be asked to attend either in-person or virtual study visits and complete questionnaires.

02

Conditions studied

  • Complex Regional Pain Syndrome
03

In context

Complex Regional Pain Syndromes

205 studies on the registry are indexed under Complex Regional Pain Syndromes; 55 are open to participants now.

This study's planned enrollment of 120 is above the median of 40 across 152 interventional studies indexed under Complex Regional Pain Syndromes.

Browse Complex Regional Pain Syndromes studies →

Lead sponsor

Stanford University is the lead sponsor of 2,168 studies on the registry; 431 are open to participants now.

Of its 267 completed or terminated interventional studies of FDA-regulated products, 207 (78%) have results posted.

Browse Stanford University studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 70 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Upper and/or lower extremity CRPS
  • On stable treatment for 1 month
  • CRPS for at least 1 year
  • Meet the Budapest criteria for CRPS at time of the study.

Exclusion criteria

Exclusion Criteria:

  • Any known allergy to naltrexone or naloxone
  • Use of prescription opioid analgesics or illegal opioid use
  • Current or planned pregnancy.
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
120 participants (estimated)

Study arms

  • Experimental
    LDN

    Naltrexone HCL, 4.5 mg, Once a day.

    Drug: LDN

  • Placebo comparator
    Placebo

    Sugar pill

    Drug: Placebo

Interventions

  • DrugLDN
  • DrugPlacebo

    Sugar pill

06

What researchers measure

Primary outcomes

  1. Changes in pain severity

    Daily pain reports on a 0-10 numerical rating scale for pain, where 0=no pain and 10=pain as bad as you can imagine

    Time frame: Approximately 4 weeks after conclusion of treatment.

07

Study locations

1 of 1 sites recruiting
08

Timeline

Tracking since Sep 25, 2026
Not marked actual or estimatedDates not marked actual or estimated

The record gives a start of Jun 2015, a primary completion of Jul 2027 and a completion of Jul 2027. It does not say whether these dates are actual or estimated.

How these figures are worked out, and which studies are left out of them.

Registered
Jul 15, 2015
First posted
Jul 20, 2015
Start
Jun 2015
Primary completionEst.
Jul 2027
CompletionEst.
Jul 2027
Last update
May 29, 2025
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on May 29, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT02502162
Lead sponsor
Stanford University
Responsible party
Sean Mackey (Redlich Professor Departments of Anesthesiology, Perioperative and Pain Medicine | Neurosciences | Neurology (by courtesy), Chief, Division of Pain Medicine, Director, Stanford Systems Neuroscience and Pain Lab (SNAPL), Stanford University, Stanford University) — Principal investigator
First posted
Jul 20, 2015
Start date
Jun 2015
Primary completion
Jul 2027 (estimated)
Completion
Jul 2027 (estimated)
Last update
May 29, 2025

Study contacts

Birute Gedrimaite
Contact
birute@stanford.edu
(650) 497-0485
Sean Mackey, MD, PhD
principal investigator · Stanford University

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

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