Opioidergic and Noradrenergic Systems in Central Parkisonian Pain

Launched by HOSPICES CIVILS DE LYON · Aug 11, 2025

Keywords

ClinConnect Summary

This clinical trial is studying how certain brain systems involved in pain control—specifically the opioid and noradrenergic systems—work differently in people with Parkinson’s disease who experience central pain compared to those who do not. Using advanced brain imaging techniques, researchers hope to better understand why some Parkinson’s patients feel chronic pain, which could help improve future treatments.

To take part, you must have a confirmed diagnosis of Parkinson’s disease and be on a stable Parkinson’s medication regimen. Participants will be divided into groups based on whether they have ongoing central pain or not. People with significant cognitive problems, severe depression, or certain medical devices that prevent MRI or PET scans cannot join. During the study, participants will undergo brain scans to look at specific receptors related to pain processing. The study is not yet recruiting, and anyone interested should be aware that stopping certain pain medications before scanning may be required. This research aims to provide new insights into how pain affects people with Parkinson’s and how it might be better managed in the future.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • Diagnosis of Parkinson's disease based on MDS-UPDRS criteria (Group 1 and 2)
• • Dopaminergic therapy stable with stable dose for at least 4 weeks prior to J0
• • Affiliate to a social security or similar system
• • Having given written consent to participate in the study, free and informed.
• • Having chronic pain more than 3 month (Group 1)
• • Without chronic pain (Groupe 2 and 3)
• • Having central pain using specific algorithm (Marques et al., 2019)
• • Having pain intensity at least 4 on VAS (Visual Analogue Scale) during the last month (Group 1)
• • Having pain intensity lower than 3 on VAS (Visual Analogue Scale) during the last month (Group 2 and 3)
• Exclusion Criteria:
• • Having atypical Parkinson's disease (Group 1 and 2)
• • Parkinson's disease with disabling dyskinesia and/or severe tremor (Group 1 and 2)
• • Any contraindications to having a brain MRI or PET scan (e.g., pacemaker, metal foreign body, claustrophobia, deep brain stimulation or apomorphin pump unable to be turn off)
• • History of head trauma with loss of consciousness lasting more than 30 minutes
• • Not agreeing to be informed in the event of incidental discovery of an abnormality on MRI or during neuropsychological assessment
• • Presence of cognitive dysfunction (defined as MoCA score \< 24)
• • Severe depression (BDI \> 29)
• • unable to stop the opioid treatment the week before the imaging exam ( e.g., Antarène codéine, Claradol codéine, Codoliprane, Dafalgan codéine, Euphon, Klipal, Lindilane, Néo-codion, Paderyl, Prontalgine, Pulmoserum, Tussipax ; Opium : Izalgi, Lamaline, Colchimax, Dropizal ; Morphine : Actiskenan, Moscontin, Oramorph, Sevredol, Skenan ; Buprénorphine : Bupensan, Buvidal, Orobupre, Sixmo, Suboxone, Subutex, Temgesic, Zubsolv ; Dihydrocodéine : Dicodin ; Hydromorphone : Sophidone ; Nalbuphine : Nalpain ; Fentanyl : Abstral, Actiq, Breakyl, Durogesic, Effentora, Instanyl, Matrifen, Pecfent, Recivit ; Méthadone : Methadone AP-HP, Zorvon ; Oxycodone : Oxsynia, Oxycontin, Oxynorm, Oxynormoro ; Tramadol : Biodalgic, Contramal, Ixprim, Monoalgic, Monocrixo, Orozamudol, Skudexum, Topalgic, Zaldiar, Zamudol, Zumalgic)
• • unable to stop any treatment
• • Treated with level 1 analgesics (NSAIDs, acetaminophen) or coanalgesics (antidepressants, antiepileptics) unless treatment has been stable for at least 4 weeks prior to the study and does not interfere with the noradrenergic system (list above).
• • Presenting or having presented a dependence on any addictive substance according to DSM-IV-TR criteria, with the exception of tobacco.
• • Having used recreational drugs interfering with the opioid and noradrenergic systems (cannabis, CBD, opiates, MDMA, ecstasy) in the last 3 months or chronic use
• • Pregnant women, women in labor or nursing mothers
• • Persons deprived of their liberty by judicial or administrative decision
• • Under psychiatric care
• • Admitted to a health or social institution for purposes other than research
• • Under legal protection (guardianship, curatorship)
• • Participant in another interventional study with an exclusion period still in progress at pre-inclusion
• • Having exceeded the annual amount of compensation authorized for participation in research protocols