Three Regimens of Ketamine Infusion in Complex Regional Pain Syndrome

Study Overview
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Brief Summary
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To evaluate the efficacy of three regimens of sub anesthetic dose of ketamine infusion in relieving chronic refractory pain in patients with complex regional pain syndrome

Detailed Description
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Ketamine N-methyl-D-aspartate (NMDA) receptor blocker that has recently been studied for its analgesic effect is a phencyclidine or phenyl cyclohexyl piperidine (PCP) derivative that initially became commercially available for human use in 1970 as a rapid-acting intravenous (IV) anesthetic. It is currently classified by the Food and Drug Administration (FDA) as an anesthetic induction agent in doses ranging from 1 to 4.5 mg/kg. Ketamine has proven to be a desirable drug, despite of its induction dissociative effects and abuse potential. It is favorable due to its short half-life and lack of clinically significant respiratory depression. In addition to its anesthetic effects, ketamine has analgesic, anti-inflammatory, and antidepressant activities.

Official Title
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Assessment of Three Regimens of Ketamine Infusion in Complex Regional Pain Syndrome: Randomized Prospective Comparative Study

Conditions
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Ketamine Infusion, Complex Regional Pain Syndromes

Intervention / Treatment
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* Drug: Ketamine
* Drug: Ketamine
* Drug: Ketamine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged more than 21 years old of both sexes with American Standards Association I ,II. Patients diagnosed as ( CRPS) based on Budapest criteria The average daily pain intensity required on (NRS) is 7 or more for at least 3 months despite of standard therapy which includes: (pharmacologic therapy as non steroidal anti- inflammatory drugs (NSAIDs), antiepileptic (AEDs), antidepressants), as well as physical therapy and psychiatric care Exclusion Criteria: patients refusal Patients with unstable psychological or psychiatric conditions, including : untreated bipolar disorder, post-traumatic stress disorder, major depression , severe personality disorder and psychotic illness. Patients have recently undergone major interventional pain procedures, such as nerve blocks or implantable therapies within 3 months of enrollment. Patients with known drug dependency or substance use disorder specifically related to ketamine or other psycho-stimulant drugs. Patients with previous severe reactions, contraindication or allergy to ketamine. Patients with cardiovascular disease (hypertension, arrhythmia), hepatic, renal or other organ impairment.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group A<br>patients will receive ketamine parenteral infusion (0.35 mg/kg/h or maximum 24mg/h) at post anesthetic care unit(PACU) over 6 hours for 3days | Drug: Ketamine<br>* patients will receive ketamine parenteral infusion (0.35 mg/kg/h or maximum 24mg/h) at post anesthetic care unit(PACU) over 6 hours for 3days .<br>|
| Experimental: Group B<br>patients will receive ketamine parenteral infusion (0.35 mg/kg/h or maximum 24mg/h ) at post anesthetic care unit(PACU) over 6 hours for 5 days . | Drug: Ketamine<br>* patients will receive ketamine parenteral infusion (0.35 mg/kg/h or maximum 24mg/h ) at post anesthetic care unit(PACU) over 6 hours for 5 days<br>|
| Experimental: Group C<br>patients will receive ketamine parenteral infusion (0.35 mg/kg/h or maximum 24mg/h ) at post anesthetic care unit(PACU) over 6 hours for 7 days | Drug: Ketamine<br>* patients will receive ketamine parenteral infusion (0.35 mg/kg/h or maximum 24mg/h ) at post anesthetic care unit(PACU) over 6 hours for 7 days<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| degree of chronic pain reduction | using Brief Pain Inventory short form (BPI-SF) questionnaire. It is a 9 item self-administered questionnaire used to evaluate the severity of a patient's pain and the impact of this pain on the patient's daily functioning. The patient is asked to rate their worst, least, average, and current pain intensity, list current treatments and their perceived effectiveness, and rate the degree that pain interferes with general activity, mood, walking ability, normal work, relations with other persons, sleep, and enjoyment of life on a 10 point scale. | up to 3 months post infusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reduction of the degree of chronic pain score | Numerical rating scales (NRS) is an 11-point scale for patient self-reporting of pain. It is based solely on the ability to perform activities of daily living (ADLs) with 0 being no pain and 10 being the worst pain imaginable | up to 3 months post infusion | 
| Side effects | Headache, Nausea and vomiting | up to 3 months post infusion |