An observational study in Fibromyalgia, sponsored by Wilderman Medical Clinic. Enrolling by invitation at 1 site in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-03.
Sponsored by Wilderman Medical Clinic · Observational
Previous studies of intravenous ketamine, which is a non-competitive N-methyl-D aspartate receptor antagonist, for fibromyalgia pain relief are limited to three studies. Two studies have focused on short-term pain relief of intravenous ketamine by measuring the patients' pain levels immediately before and after the infusion. Currently, existing studies used short-term infusions (30-40 minutes) of sub-anesthetic doses of ketamine for pain relief in fibromyalgia patients, whereas the Consensus Guidelines on the Use of Intravenous Ketamine Infusions for Chronic Pain from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, and the American Society of Anesthesiologists recommend infusing IV ketamine for at least two hours and a minimal total dose of 80 mg.
The rationale of this study is to expand on the existing data of safety and efficacy of intravenous ketamine to relieve fibromyalgia pain. Specifically, this investigation will add data to fill the existing gap regarding the short- and long-term pain relief in the treatment of fibromyalgia with intravenous ketamine infusions. The study will also attempt to determine safety and tolerability. In addition, the characteristics of treatment responders versus non-responders will be assessed in an effort to determine whether specific characteristics can be used to predict treatment response in this group of patients.
This study consists of two parts. The first part is a single-centre, retrospective chart review to analyze and summarize the investigators' experience with intravenous ketamine infusions in the treatment of patients with fibromyalgia who received at least four infusions for pain management. For the second part, patients who already received at least three intravenous ketamine infusions (for optimal dose determination) will be enrolled in an open single-group prospective study to receive one intravenous ketamine treatment. In this prospective study, the investigators will evaluate infusion effectiveness, safety, and tolerability as well as the influence of patients' demographic and medical characteristics, including depression status and ketamine dissociation symptoms, on the treatment outcome.
This two-part study aims to evaluate whether intravenous ketamine is effective in reducing pain in patients diagnosed with fibromyalgia. To achieve this goal, the study will assess the effect of intravenous ketamine infusions on short- and long-term pain relief. The study will also evaluate the safety and tolerability of ketamine infusions in fibromyalgia patients and factors that may have an impact on the treatment outcome.
Patients will be recruited from Wilderman Medical Clinic, a chronic pain clinic located in Thornhill, Ontario. The clinic consists of state-of-the-art out-patient facilities, an interdisciplinary team and nursing support.
To be included in Part 1 of the study, patients must fulfil the following criteria:
To be included in Part 2 of the study, patients must fulfil the following criteria:
Exclusion Criteria:
Patients will be excluded from Part 1 of the study if they meet any of the following criteria:
Patients will be excluded from the Part II of the study if they meet any of the following criteria:
A total of approximately 30 patients diagnosed with fibromyalgia will be selected for participation in the study, all of whom will be treated with one IV ketamine infusion for pain relief according to their regular schedule of IV ketamine infusions. Each patient will be evaluated at baseline (prior to ketamine infusion), 40 minutes post-infusion, and at follow up visits.
Drug: Intravenous Ketamine Infusions
A total of approximately 20 patients will be selected for participation in the study, all of whom were treated with IV ketamine infusions. Information regarding clinically relevant outcomes will be obtained from chart reviews from patients who meet the eligibility criteria. The patient's response to treatment will be assessed.
Drug: Intravenous Ketamine Infusions
Ketamine will be slowly infused with the routine target dose 1.5-2 mg/kg over 3-4 hours.
Numeric Rating Scale (NRS)
The NRS is a standardized, one-dimensional measure of pain intensity. The pain intensity is rated by the participant using a scale from 0-10; 0 being the least (no pain) to 10 (worst pain imaginable).
Time frame: Baseline visit: immediately before IV ketamine infusion
Numeric Rating Scale (NRS)
The NRS is a standardized, one-dimensional measure of pain intensity. The pain intensity is rated by the participant using a scale from 0-10; 0 being the least (no pain) to 10 (worst pain imaginable).
Time frame: Baseline visit: immediately after the IV ketamine infusion
Numeric Rating Scale (NRS)
The NRS is a standardized, one-dimensional measure of pain intensity. The pain intensity is rated by the participant using a scale from 0-10; 0 being the least (no pain) to 10 (worst pain imaginable).
Time frame: Follow-up visits at 1, 2, 3, and 4 weeks after the IV ketamine infusion
Integral of pain relief
IPR is a multidimensional measure combining the duration of patients' pain relief (in days) and the percentage of pain relief that they had experienced. IPR seeks to tap into a fuller picture of the patients' pain relief, since it not only measures current pain levels, but patients' experience of pain, both in duration and percentage of relief, over a longer period of time. The scale has no restrictions, beginning at 0 (no treatment effect). Therefore, the higher the IPR value, the more effective the treatment was at reducing pain
Time frame: Follow-up visits at 1, 2, 3, and 4 weeks after the IV ketamine infusion
The Clinician-Administered Dissociative States Scale (CADSS)
The CADSS is a 27-item scale with 19 subject-rated items and 8 items scored by an observer. The subjective component consists of 19 items which are administered by a clinician who begins each question with the phrase "at this time" and then reads the item to the subject. The subject then endorses one of a range of possible responses: 0 = not at all, 1 = slightly, 2 = moderately, 3 = considerably, 4 = extremely. The subject's response on these 0 to 4 scales is recorded and the clinician moves on to the next item. Three non-empirically derived subscales for the CADSS have been proposed: amnesia (two items), depersonalization (five items), and derealization (12 items).
Time frame: Baseline visit: immediately before IV ketamine infusion
The Clinician-Administered Dissociative States Scale (CADSS)
The CADSS is a 27-item scale with 19 subject-rated items and 8 items scored by an observer. The subjective component consists of 19 items which are administered by a clinician who begins each question with the phrase "at this time" and then reads the item to the subject. The subject then endorses one of a range of possible responses: 0 = not at all, 1 = slightly, 2 = moderately, 3 = considerably, 4 = extremely. The subject's response on these 0 to 4 scales is recorded and the clinician moves on to the next item. Three non-empirically derived subscales for the CADSS have been proposed: amnesia (two items), depersonalization (five items), and derealization (12 items).
Time frame: Baseline visit: 40 minutes after the IV ketamine infusion
Patient Health Questionnaire (PHQ-9)
PHQ-9 is endorsed by the National Institute for Health and Clinical Excellence for use in primary care in measuring baseline depression severity and responsiveness to treatment. The 9 items on the PHQ-9 consist of the 9 criteria on which the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) depressive disorder diagnoses are based. A 4-point scale indicates a degree of severity; items are rated from 0 (not at all) to 3 (nearly every day).
Time frame: Baseline visit: before IV ketamine infusion
Patient Health Questionnaire (PHQ-9)
PHQ-9 is endorsed by the National Institute for Health and Clinical Excellence for use in primary care in measuring baseline depression severity and responsiveness to treatment. The 9 items on the PHQ-9 consist of the 9 criteria on which the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) depressive disorder diagnoses are based. A 4-point scale indicates a degree of severity; items are rated from 0 (not at all) to 3 (nearly every day).
Time frame: Follow-up visits at 1, 2, 3, and 4 weeks after the IV ketamine infusion
Self-completed Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS)
The LANSS is a simple and valid 7-item tool for identifying patients whose pain is dominated by neuropathic mechanisms. Each item is a binary response (yes or no) to the presence of symptoms (5 items) or clinical signs (2 items). S-LANSS is a modified version of the LANSS pain scale to make it capable of self-completion.
Time frame: Baseline visit: before IV ketamine infusion
Self-completed Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS)
The LANSS is a simple and valid 7-item tool for identifying patients whose pain is dominated by neuropathic mechanisms. Each item is a binary response (yes or no) to the presence of symptoms (5 items) or clinical signs (2 items). S-LANSS is a modified version of the LANSS pain scale to make it capable of self-completion.
Time frame: Follow-up visits at 1, 2, 3, and 4 weeks after the IV ketamine infusion
Fibromyalgia Impact Questionnaire, Revised (FIQR)
The Fibromyalgia Impact Questionnaire (FIQ) is a commonly used instrument in the evaluation of fibromyalgia patients. The revised FIQ has 21 individual questions. All questions are based on an 11-point numeric rating scale of 0 to 10, with 10 being 'worst'. All questions are framed in the context of the past 7 days. The FIQR is divided into three linked sets of domains: (a) 'function' (contains 9 questions), (b) 'overall impact' (contains 2 questions), and (c) 'symptoms' (contains 10 questions). The FIQR is an updated version of the FIQ that has good psychometric properties, can be completed in less than 2 minutes and is easy to score.
Time frame: Baseline visit: before IV ketamine infusion
Fibromyalgia Impact Questionnaire, Revised (FIQR)
The Fibromyalgia Impact Questionnaire (FIQ) is a commonly used instrument in the evaluation of fibromyalgia patients. The revised FIQ has 21 individual questions. All questions are based on an 11-point numeric rating scale of 0 to 10, with 10 being 'worst'. All questions are framed in the context of the past 7 days. The FIQR is divided into three linked sets of domains: (a) 'function' (contains 9 questions), (b) 'overall impact' (contains 2 questions), and (c) 'symptoms' (contains 10 questions). The FIQR is an updated version of the FIQ that has good psychometric properties, can be completed in less than 2 minutes and is easy to score.
Time frame: Follow-up visits at 1, 2, 3, and 4 weeks after the IV ketamine infusion
Patients Global Impression of Change (PGIC)
PGIC is a seven-point single-item scale ranging from 'very much worse' to 'very much improved' worse' with 'no change' as the mid-point that evaluates improvement with treatment during a clinical trial.
Time frame: Follow-up visits at 1, 2, 3, and 4 weeks after the IV ketamine infusion
Periprocedural adverse effects
Variations of heart rate (beats per minute)
Time frame: Baseline visit: During the infusion
Periprocedural adverse effects
Variations of blood pressure (mmHg)
Time frame: Baseline visit: During the infusion
Periprocedural adverse effects
Variations of pulse oxygen saturation (percentage of hemoglobin carrying oxygen)
Time frame: Baseline visit: During the infusion
Periprocedural adverse effects
Presence of dizziness, nausea, chest pain, shortness of breast
Time frame: Baseline visit: During the infusion
Postprocedural adverse effects
Variations of heart rate (beats per minute)
Time frame: Baseline visit: During 60-90 minutes after the procedure
Postprocedural adverse effects
Variations of blood pressure (mmHg)
Time frame: Baseline visit: During 60-90 minutes after the procedure
Postprocedural adverse effects
Variations of pulse oxygen saturation (percentage of hemoglobin carrying oxygen)
Time frame: Baseline visit: During 60-90 minutes after the procedure
Postprocedural adverse effects
Presence of dizziness, nausea, chest pain, shortness of breast
Time frame: Baseline visit: During 60-90 minutes after the procedure
Plan to share: No — IPD will be available according to reasonable demands.
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