- Phase 1 – Patient Global Impression of Change (PGIC) [ Time Frame: participants will be followed for the duration of an 4 hour, single day human laboratory experiment, and this outcome will be measured 3 times after study medication is provided during the treatment day ]
a 7 point ordinal scale reflective of improvement in pain
- Phase 1 – von Frey test [ Time Frame: participants will be followed for the duration of an 4 hour, single day human laboratory experiment, and the outcome will be measured once before they receive study medication and then 3 additional times during the treatment day ]
The von Frey filament will be applied on the dorsum of the more painful foot until bending is observed for 3 seconds, followed by a VAS pain rating
- Phase 1 – Marijuana subscale (M-scale) of the Addiction Research Center Inventory (ARCI) [ Time Frame: participants will be followed for the duration of an 4 hour, single day human laboratory experiment, and the outcome will be measured once before they receive study medication and then 3 additional times during the treatment day ]
The M -scale has 12 true/false statements describing the subjective effects of marijuana
- Phase 1 – Neuropsychological Assessment Battery [ Time Frame: participants will be followed for the duration of an 4 hour, single day human laboratory experiment, and the outcome will be measured once before they receive study medication and then 3 additional times during the treatment day ]
Testing will include the Wechsler Adult Intelligence Scale (WAIS-III) Digit Symbol, Hopkins Verbal Learning Test-Revised and Grooved Pegboard Test (motor)
- Phase 1 – heart rate variability [ Time Frame: participants will be followed for the duration of an 4 hour, single day human laboratory experiment, and the outcome will be measured once before they receive study medication and then 3 additional times during the treatment day ]
Heart Rate Variability (HRV) correlates with the level of pain intensity. Persons with effective analgesic treatment of chronic pain exhibited improved HRV relative to pain sufferers with ineffective treatment suggesting HRV may serve as a pain biomarker
- Phase 1 – store plasma samples for evaluation of THC, CBD, and endocannabinoid system biomarkers [ Time Frame: participants will be followed for the duration of an 4 hour, single day human laboratory experiment, and the outcome will be measured once before they receive study medication and then 3 additional times during the treatment day ]
Cannabinoid and endocannabinoid levels in plasma will be quantified using a liquid chromatography-tandem mass spectrometry (LC/MS)
Our objective is to assess 120 community-dwelling people living with HIV who have neuropathic pain and are currently using cannabis. These participants will be enrolled in a study that consists of two phases:
Phase 1) This will involve a cross over study involving three different doses of vaporized cannabis that contain THC and varying concentrations of CBD, including a) 3.74% THC + 0.49% CBD, b) 3.49% THC + 4.17% CBD, and c) 3.11% THC + 15.76% CBD. This phase will examine the acute effects of cannabis on pain intensity, blood endocannabinoid levels, and the relationship of pain with heart rate variability (HRV).
Phase 2) This phase will involve the association between dispensary-obtained cannabis and changes in pain reported via IMPACT, a mHealth text messaging program that will serve as a useful tool to monitor the relationship between pain and cannabis use. Text messaging is an effective method to modify health behaviors, monitor substance use, and track pain. Our group has recently demonstrated the feasibility of using short message service (SMS) texting to promote anti-retroviral therapy adherence and monitor daily methamphetamine (METH) use in persons living with HIV neuropathy with bipolar disorder or METH dependence.