Effects of Vaporized Marijuana on Neuropathic Pain

Phase 1

Completed

Conditions: Neuropathic Pain
Reflex Sympathetic Dystrophy
Peripheral Neuropathy
Post-herpetic Neuralgia
Spinal Cord Injury
Multiple Sclerosis

Interventions: Drug: Mild dose cannabis
Drug: Cannabis
Drug: Low dose cannabis

Brief Summary: This study theorized that a low dose of vaporized cannabis could alleviate nerve injury pain.

Detailed Description: We conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Thirty-nine patients with central and peripheral neuropathic pain underwent a standardized procedure for inhaling medium-dose (3.53%), low-dose (1.29%), or placebo cannabis with the primary outcome being visual analog scale pain intensity. Psychoactive side effects and neuropsychological performance were also evaluated.

Recruitment & Eligibility

Inclusion Criteria

Age greater than 18 and less than 70
Visual Analogue Scale (VAS pain intensity) greater than 3/10
A negative urine drug screening test, i.e., no evidence of IV drug abuse
Neuropathic pain due to reflex sympathetic dystrophy, peripheral neuropathy, post-herpetic neuralgia, post-stroke pain, multiple sclerosis or spinal cord injury

Exclusion Criteria

Presence of another painful condition of greater severity than the neuropathic pain condition which is being studied.
Subjects with moderate-severe major depression, bipolar/mania, bipolar II/hypomania and schizophrenia or schizoaffective disorder.
Unstable Type 1 or 2 diabetes defined as blood glucose more than 156 mg/dl
History of traumatic brain injury
Uncontrolled medical condition, including coronary artery disease, hypertension, cerebrovascular disease, asthma, tuberculosis (TB), chronic obstructive pulmonary disease (COPD), opportunistic infection, malignancy requiring active treatment, active substance abuse (alcohol or injection drugs).
Current use of marijuana (e.g., within 30 days of randomization)
Pregnancy as ascertained by a self-report and a mandatory commercial pregnancy test.

Arm && Interventions

Primary Outcome Measures

Name	Time	Method
Participants With 30% or Greater Reduction in Pain Intensity	baseline to six hours	The primary outcome variable, VAS Pain Intensity, was assessed by asking participants to indicate the intensity of their current pain on a 100-mm visual analog scale (VAS) between 0 (no pain) and 100 (worst possible pain).An assessment was performed before the administration of vaporized cannabis or placebo and hourly thereafter for six hours.

Secondary Outcome Measures

Name	Time	Method
Visual Analogue Scale Pain Intensity Scores for Baseline and up to 5 Hours Following Administration of Vaporized Cannabis	baseline to six hours	The pain intensity scores for all of the time points (i.e., baseline prior to administration and up to 5 hours following administration of cannabis). VAS Pain Intensity was assessed by asking participants to indicate the intensity of their current pain on a 100-mm visual analog scale (VAS) between 0 (no pain) and 100 (worst possible pain).