Ketamine and fMRI for Neuropathic Pain

• Status: Completed
• Trial end date: 2020-12-01
• Target enrollment: 0
• Participant gender: All

Summary

Neuropathic or nerve injury related pain (NP), an extremely unpleasant condition that is difficult to treat, often has a severe, persistent, and unremitting course. Conventional treatments are often ineffective in relieving NP. Recently, the investigators have developed a cost-efficient regimen involving use of low dose infusions of ketamine for treating neuropathic pain in patients in whom oral medications have failed. We have observed excellent benefits in many of these patients. However, this treatment requires titration and monitoring during the infusion and currently it is not possible to predict which patients will benefit from this intervention. The investigators have shown that functional magnetic resonance imaging (fMRI) of the brain can be used as a tool to predict relief of pain and to assess the effect of treatment in some chronic pain conditions. This innovative project involves development of an fMRI-guided treatment with intravenous ketamine in patients with NP. This study aims to analyze patterns of changes in fMRI of the brain, before and after infusion of ketamine and to correlate the changes with pain intensity. The information from this study will help to deliver this therapy earlier to those patients who are most likely to benefit from ketamine.

• Phase: N/A
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: University Health Network, Toronto
• Treatments: Ketamine

Criteria

Inclusion Criteria:

• Refractory neuropathic pain diagnosed by a >3 score on DN4 (Douleur Neuropathique 4) questionnaire

• Average daily pain intensity should be moderate or severe, as indicated by a >3 score on NRS (Numerical Rating Scale)

• Duration of neuropathic pain should be more than three months

• Participants should have tried at least three medications for neuropathic pain. Each of these medications should belong to a different pharmacological group: anticonvulsants (gabapentin, pregabalin), tricyclic antidepressants (amitriptyline, nortriptyline, imipramine, desipramine), serotonin noradrenaline reuptake inhibitors (venlafaxine, duloxetine), tramadol, opioids, cannabinoids, methadone, topical lidocaine and capsaicin patches.

Exclusion Criteria:

• Ketamine or lidocaine intravenous infusion within the 6 months preceding enrollment into this trial

• Contraindications to ketamine (allergy, pregnancy, uncontrolled arterial hypertension, uncontrolled hyperthyroidism, severe ischemic heart disease or heart failure, severe liver or kidney disease, space occupying lesion in the brain or the spinal cord, uncontrolled epilepsy and glaucoma)

• Ongoing litigation issues related to the patient's pain that may affect reporting of pain and quality of life

• An unstable medical or psychiatric condition that makes it unsafe to use study medications

• Participants unable to comply with the study protocol (e.g. follow-up visits, filling forms for measuring anxiety, depression, and quality of life)

• Relative (claustrophobia) or absolute contraindications for MRI