Effects of PR Oxycodone and of Levodopa, vs Placebo, on Central Neuropathic Pain in Parkinson's Disease (OXYDOPA)

April 28, 2026 updated by: University Hospital, Toulouse

Evaluation of the Analgesic Effects of Prolonged-release Oxycodone and of Levodopa, Versus Placebo, on Central Neuropathic Pain in Parkinson's Disease: OXYDOPA Trial

This study will be conducted in three parallel groups receiving oxycodone, levodopa or placebo, administered as an add-on therapy, in addition to the usual antiparkinsonian treatment. As this study focuses on chronic central neuropathic pain caused by PD, the effects of study treatments will be evaluated after a 10-week treatment period

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The treatment period (11 weeks) will be divided into three periods:

  1. A titration phase of two weeks, during which of the doses of the treatments will be gradually increased in three steps:

    Level 1 (from D1 to D5):

    • Oxycodone: 10 mg PR/day bid (5 mg PR/5 mg PR)
    • Levodopa: 100 mg/day bid (50 mg/50 mg)

    Level 2 (from D6 to D10):

    • Oxycodone: 20 mg PR/day tid (10 mg/0 mg/10 mg)
    • Levodopa: 150 mg/day tid (50 mg/50 mg/50 mg)

    Level 3 (from D11to D15):

    • Oxycodone: 40 mg PR/day tid (20 mg/0 mg/20 mg)
    • Levodopa: 200 mg/day tid (100 mg/50 mg/50 mg)
  2. A fixed dose period: the level 3 dose will be maintained for 8 weeks (from D16 to D71). The study treatment will be administered as an add-on therapy, with the usual antiparkinsonian treatment. If patients have side effects at the level 3 dose, a return to the level 2 dose will be authorized.
  3. A withdrawal period: The dose of the study treatment will gradually be reduced, over an eight-day period:

For patients treated with the level 3 dose for 8 weeks: decrease to the level 2 dose over the first 3 days (from D72 to D74) ; then a decrease to the level 1 dose over the next 3 days (from D75 to D77). The treatment will be stopped completely on D78. The last visit will take place on D79, 2 days after the end of treatment.

For patients treated with the level 2 dose: decrease to the level 1 dose over the first 3 days (from D72 to D74), with stopping of the treatment on D75. The last visit will take place on D79, 5 days after the end of treatment.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
67

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • France
      • Aix-en-Provence, France, 13616
        • Hospital of Aix-en-Provence
      • Amiens, France, 80054
        • CHU Amiens
      • Bordeaux, France, 33076
        • University Hospital of Bordeaux
      • Clermont-Ferrand, France, 63003
        • University Hospital of Clermont-Ferrand
      • Créteil, France, 94010
        • Henri Mondor Hospital
      • Lille, France, 59037
        • University Hospital of Lille
      • Limoges, France, 87042
        • University Hospital of Limoges
      • Lyon, France
        • Hospital Pierre Wertheimer
      • Marseille, France, 13385
        • University Hospital of Marseille
      • Nancy, France
        • University hospital of Nancy
      • Nantes, France
        • University Hospital of Nantes
      • Nîmes, France
        • University Hospital of Nîmes - Caremeau
      • Paris, France, 75651
        • Pitié-Salpêtriere Hospital
      • Poitiers, France, 86021
        • University Hospital of Poitiers
      • Rennes, France, 35033
        • University Hospital of Rennes
      • Rouen, France, 76031
        • University Hospital of Rouen
      • Strasbourg, France, 67098
        • University Hospital of Strasbourg
      • Toulouse, France, 31059
        • CHU Toulouse

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

36 years to 71 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients with Parkinson's disease according to the UKPDSBB (United Kingdom Parkinson's Disease Society Brain Bank) criteria
  • Patients suffering from chronic pain (lasting for more than 3 months)
  • Patients suffering from central neuropathic pain caused by PD,
  • Patients with a PD-related central neuropathic pain intensity of at least 3 points on the VAS (average intensity over the last month),
  • Patients with both types of pain (neuropathic and nociceptive) will be included if the neuropathic pain predominates
  • Patients treated with a stable regimen of dopaminergic drugs (levodopa and/or dopamine agonists) for at least 4 weeks before the study dan throughout the study
  • Patients with a stable step 1 analgesic (NSAIDS, acetaminophen) or coanalgesic (antidepressants, antiepileptic) treatment for at least 4 weeks before the study and throughout the study

Exclusion Criteria:

  • Patients suffering from another parkinsonian syndrome
  • De Novo patients (patients never before treated with dopaminergic drugs)
  • Patients with intercurrent acute pain
  • Patients suffering from a chronic disease causing pain (rheumatoid arthritis, ankylosing spondylitis, diabetic neuropathy, cancer etc.)
  • Patients treated with neuroleptics
  • Patients with clinically detectable behavioural disorders and addiction
  • Patients with disabling dyskinesias
  • Patients with painful restless legs syndrome
  • Patients with cognitive impairment (MMS < 25) or unable to complete the various scales used in the study
  • Hypersensitivity to oxycodone, levodopa, benserazide or a combination of these drugs
  • Patients treated with opioid drugs (step 2 and 3)
  • Patients treated with non-selective monoamine oxidase inhibitors (MAOI)
  • Patients with severe hepatocellular insufficiency
  • Patients with uncontrolled cardiovascular and pulmonary diseases
  • Persistent constipation that has already resulted in a subocclusive state
  • Patients treated with antiemetic neuroleptics
  • Patients with angle-closure glaucoma

Exclusion criteria relating to MRI:

  • Patients with claustrophobia
  • Patients with a hearing aid, cardiac prosthesis, pacemaker, surgical clip
  • Patients refusing to be informed of abnormalities are detected on MRI

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: PR oxycodone

A titration phase of two weeks, in three steps:

Level 1 (from D1 to D5):

  • Oxycodone : 10 mg PR/day bid (5 mg PR/5 mg PR)
  • Levodopa placebo 100 mg/day bid (50 mg/50 mg)

Level 2 (from D6 to D10):

  • Oxycodone : 20 mg PR/day tid (10 mg/0 mg/10 mg)
  • Levodopa placebo: 150 mg/day tid (50 mg/50 mg/50 mg)

Level 3 (from D11to D15):

  • Oxycodone: 40 mg PR/day tid (20 mg/0 mg/20 mg)

  • Levodopa placebo: 200 mg/day tid (100 mg/50 mg/50 mg)

    • A fixed dose period: the level 3 dose will be maintained for 8 weeks (from D16 to D71).
    • A withdrawal period:
Drug: PR Oxycodone
PR Oxycodone
Other Names:
  • PR Oxycontin
Drug: Levodopa placebo
Active Comparator: levodopa

A titration phase of two weeks, in three steps:

Level 1 (from D1 to D5):

  • Oxycodone placebo : 10 mg PR/day bid (5 mg PR/5 mg PR)
  • Levodopa 100 mg/day bid (50 mg/50 mg)

Level 2 (from D6 to D10):

  • Oxycodone placebo: 20 mg PR/day tid (10 mg/0 mg/10 mg)
  • Levodopa : 150 mg/day tid (50 mg/50 mg/50 mg)

Level 3 (from D11to D15):

  • Oxycodone placebo: 40 mg PR/day tid (20 mg/0 mg/20 mg)

  • Levodopa : 200 mg/day tid (100 mg/50 mg/50 mg)

    • A fixed dose period: the level 3 dose will be maintained for 8 weeks (from D16 to D71).
    • A withdrawal period:
Drug: Levodopa
Levodopa
Other Names:
  • Modopar
Drug: Oxycodone Placebo
Placebo of PR Oxycodone
Placebo Comparator: Placebo

A titration phase of two weeks, in three steps:

Level 1 (from D1 to D5):

  • Oxycodone placebo : 10 mg PR/day bid (5 mg PR/5 mg PR)
  • Levodopa placebo 100 mg/day bid (50 mg/50 mg)

Level 2 (from D6 to D10):

  • Oxycodone placebo: 20 mg PR/day tid (10 mg/0 mg/10 mg)
  • Levodopa placebo: 150 mg/day tid (50 mg/50 mg/50 mg)

Level 3 (from D11to D15):

  • Oxycodone placebo: 40 mg PR/day tid (20 mg/0 mg/20 mg)

  • Levodopa placebo: 200 mg/day tid (100 mg/50 mg/50 mg)

    • A fixed dose period: the level 3 dose will be maintained for 8 weeks (from D16 to D71).
    • A withdrawal period:
Drug: Levodopa placebo
Drug: Oxycodone Placebo
Placebo of PR Oxycodone

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Average pain intensity
Time Frame: 8 weeks
Change in average pain rated on visual analog scale (VAS) intensity between baseline and after 8 weeks
8 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Maximal pain intensity
Time Frame: 8 weeks
Change of maximal pain intensity over the preceding week rated on the VAS
8 weeks
Functional impact of pain" of the Brief Pain Inventory (BPI)
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Neuropathic Pain Symptoms Inventory (NPSI)
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
McGill pain questionnaire (SFMPQ)
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Depression and anxiety: the Hospital Depression and Anxiety (HAD) scale
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Apathy: the Lille Apathy Rating Scale (LARS)
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Fatigue : the Parkinson fatigue scale
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Sleep : the Pittsburgh sleep quality index
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Motor assessment and motor fluctuations: MDS UPDRS (MDS Movement Disorder Society - UPDRS Unified Parkinson Disease Rating Scale)
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Quality of life: Parkinson's Disease Questionnaire 39 items (PDQ-39)
Time Frame: 8 weeks
Change in scores between Day 0 and Day 71(Day 71= 8 weeks of treatment)
8 weeks
Acetaminophen consumption reported in diary
Time Frame: 8 weeks
number of pills or capsules reported in patients diary
8 weeks
Adverse events
Time Frame: Day 5, Day 10, Day 15, Day 43, Day 71, Day 79
Adverse events, evaluated with an open-ended questionnaire
Day 5, Day 10, Day 15, Day 43, Day 71, Day 79
changes in Resting-state brain network (3T fMRI)
Time Frame: Day 0 /Day 71(Day 71= 8 weeks of treatment)
changes in resting-state cerebral networks between Day 0 and Day 71, as assessed by 3T fMRI.
Day 0 /Day 71(Day 71= 8 weeks of treatment)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital, Toulouse

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Christine Brefel-Courbon, MD, University Hospital, Toulouse
  • Study Chair: Claire THALAMAS, MD, University Hospital, Toulouse

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2016

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2020

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 17, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 9, 2015

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 10, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 4, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 14 7440 01

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Parkinson Disease

Clinical Trials on PR Oxycodone

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings