The Effect of Outpatient Ketamine Infusion on Chronic Neuropathic Pain and PTSD

This study is aimed to evaluate outpatient ketamine infusion within a military chronic neuropathic pain population and its effect on PTSD. Currently, this is a pilot study with 30 participants. Participants will be randomized to (1) a moderate dose ketamine, (2) moderate dose ketamine +Mg, or (3) a magnesium control group. Participants will complete self-reported pain and PTSD questionnaires throughout the \~24-week study period. The outlined strategy will provide evidence for the utility of ketamine in neuropathic pain management and pain associated comorbidities within a military population.

Subjects will be recruited with no target toward ethnicity, gender, or race. Active duty, veteran, retiree, and military dependents between the ages of 18-70 years old with an established diagnosis of chronic neuropathic pain will be identified and screened for study inclusion. Enrollees will have had neuropathic pain \>3 months duration, report a pain score between 4-7, and meet inclusion/exclusion criteria for the study. Since ketamine's influence on PTSD is a secondary measure, any patients with a PCL-5 score \> 33 will be noted. After informed consent is obtained participants will be randomized into a (1) moderate dose ketamine, (2) moderate dose ketamine +Mg, or (3) a magnesium control group. The magnesium-only group will be randomly assigned to one of the treatment groups (moderate dose ketamine or moderate dose ketamine +Mg) after 2 weeks and complete the full infusion treatment regime of the randomly selected treatment group. Administration of ketamine will occur in diminishing number of dosing events: Week 1 \& 2 will consist of 3 treatments per week. Weeks 3 \& 4 will consist of 2 treatments per week. Weeks 5 \& 6 will consist of 1 treatment per week. Booster treatments will be administered week 10 and week 24. Booster treatments will only be 1 infusion that week. Participants will fill out questionnaires before and after each infusion- day concerning their pain, PTSD, anxiety, depression, and quality of life. Participants will be evaluated at least 5 days prior to the first treatment and 30-35 days after the final infusion. Participants will continue their current pain management regimen during the study and be instructed to use analgesics only as needed. Pain medication use will be recorded throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* 18-70 years old with Chronic Neuropathic Pain \>= 3 months
* Biologic male or biologic female
* Women of childbearing age will be included if there are no plans of pregnancy within the study period, the participant agrees to actively utilize contraception throughout the study, and agrees to pregnancy tests
* Active Duty, Veterans, and retirees
* Ketamine naïve for 1 year
* Moderate Neuropathic pain Scale 4-7

Exclusion Criteria:

* Cognitive dysfunction
* Psychiatric illness involving psychosis
* Neurocognitive disorder
* Patients with Traumatic Brain Injury (TBI)
* Acute cardiovascular disease or poorly controlled hypertension
* Untreated or uncontrolled thyroid disease
* Hyperthyroidism
* Severe liver or renal disease
* Renal impairment
* History of recent heart attack, vascular disease, or any other medical condition that may be deemed by a provider as a contraindication to receiving ketamine
* Active substance abuse
* Pregnant or lactating
* Patients who are planning to become pregnant within 12 weeks of treatment completion
* Elevated Blood Pressure/hypertension
* Known hypersensitivity to Ketamine
* Hemodynamic instability
* Respiratory depression
* Use of Theophylline or Aminophylline, Sympathomimetics and Vasopressin,
* Use of Benzodiazepines
* A history of drug abuse or dependence
* Active risk of substance use
* Patients who are not able to abide by the pre-treatment and posttreatment clinical protocol, such as food intake, abstaining from certain medications, unable to remain in the clinic for a minimum of 1 hour for observation, and cannot provide the name and phone number of the party who will pick them up post-treatment