Vaporized Cannabis and Spinal Cord Injury Pain

Phase 2

Completed

Brief Summary: This study will demonstrate that vaporized marijuana results in antinociception when compared to placebo in subjects with spinal cord injury. To further evaluate potential benefits and side effects, the effect of different strengths of cannabis on mood, cognition, and psychomotor performance will also be measured.

Detailed Description: This study will demonstrate that vaporized cannabis can produce antinociceptive effects compared to placebo in human subjects with spinal cord injury (SCI). A within-subject crossover study of the effects of cannabis versus placebo on spontaneous and evoked pain will be performed. A synopsis of antinociception with mood, cognitive impairment, psychomotor performance, and side effects will be obtained to help evaluate the utility of vaporized marijuana in SCI neuropathic pain.

This study will compare the analgesic and side effect profile of low (3.5%) to high dose (7.0%) delta 9-tetrahydrocannabinol in subjects with spinal cord injury pain. It is hypothesized that a low dose will produce a lesser degree of neuropsychological impairment while maintaining a similar degree of pain relief to the higher dose. The use of two different strengths will help determine tolerable dosing for the treatment of SCI neuropathic pain.

Recruitment & Eligibility

Inclusion Criteria

Age greater than 18 and less than 70
Pain intensity ≥ 4/10
Neuropathic pain defined as chronic pain in an area of sensory abnormality corresponding to the spinal cord or nerve root lesion, and the pain should have no primary relation to movement, inflammation or other local tissue damage
Leeds Assessment of Neuropathic Symptoms and Signs score greater than or equal to 12
Spinal cord injury of 3 or more months duration (to avoid spontaneous recovery obfuscating generalizability)

Exclusion Criteria

Known concomitant cerebral damage/cognitive impairment (TBI, Alzheimer's Disease Vascular dementia, Parkinson's disease, dementia with Lewy Bodies and Front temporal dementia
Clinically significant or unstable medical condition (i.e., cardiac, respiratory, hepatic or renal disease) that, in the opinion of the investigator, would compromise participation in the study
Neurologic disorders unrelated to spinal cord injury that may confound the assessment of the central neuropathic pain due to spinal cord injury (hereditary neuropathies; diabetic peripheral neuropathy; traumatic neuropathy; and immune-mediated neuropathies)
Active substance abuse within past year using "The Substance Abuse Module of Diagnostic Interview Schedule for DSM-IV
Pregnancy as ascertained by a self-report and a mandatory commercial pregnancy test
Currently on probation or parole.
Hx of Schizophrenia, Bipolar Depression with Mania, current suicidal ideation or past history of suicide attempt 8. Severe depression (Patient Health Questionnaire-9 ≥ 15) 9. Current suicidal ideation

Arm && Interventions

Group	Intervention	Description
Vaporization of Cannabis 6.7% THC	Vaporization of Cannabis	Inhaling of standardized measured puffs of Vaporized High Dose 6.7% THC. Monitored for 8 hours measuring psychoactive and analgesic effects.
Vaporization of Cannabis 2.9% THC	Vaporization of Cannabis	Inhaling standardized measured puffs of Vaporized Low Dose 2.9% THC. Monitored for 8 hours measuring psychoactive and analgesic effects.
Vaporization of Cannabis Placebo THC	Vaporization of Cannabis	Inhaling standardized measured puffs of Placebo THC. Monitored for 8 hours measuring psychoactive and analgesic effects.

Primary Outcome Measures

Name	Time	Method
Number of Participants Achieving a Reduction in Pain Intensity of 30% or More	hourly pain assessments for 8 hours	Number of participants achieving a reduction of pain intensity of 30% or more, a level believed to be clinically important, was estimated for each treatment dose.

Secondary Outcome Measures