PainRelief.com Interview with:
Donald I. Abrams, MD
Division of Hematology-Oncology
Department of Medicine,
Zuckerberg San Francisco General Hospital
University of California, San Francisco
PainRelief.com: What is the background for this study? What are the main findings?
Response: A number of years ago, Kalpna Gupta, PhD, an investigator then at the University of Minnesota, came and told me about her mice with Hemoglobin SS who experienced pain that responded to laboratory cannabinoids. She was going to apply for a grant from the National Heart, Lung and Blood Institute to continue her studies and sought us out because of our prior clinical trials with cannabis and pain. Dr. Gupta wanted to include a pilot proof of principle human study in her application and asked if we could design one. As cannabidiol (CBD) was just becoming known at that time, we suggested to do a study in patients with sickle cell disease and pain looking at a delta-9-tetrahydrocannabinol (THC)-dominant strain of inhaled cannabis, a CBD-dominant strain, a balanced 1:1 strain and placebo. She said that we would only have funds to do a two-arm study, one of which needed to be placebo. As we had already shown that there was a trend for vaporized cannabis that was predominantly THC to add to the analgesic effect of sustained-release opioids in patients with chronic pain, we chose to investigate a 4.4% THC:4.9% CBD product obtained from the National Institute on Drug Abuse.
We designed a crossover trial so that each participant would spend two 5-day inpatient stays separated by at least a month in our Clinical Research Center at Zuckerberg San Francisco General Hospital. During one stay they would add vaporized cannabis to their stable ongoing analgesic regimen and during the other stay they would inhale placebo cannabis three times a day. We use the Volcano vaporizer device that heats the plant material and not an oil as has become popular in the recent “vaping” craze. Our target was to enroll 35 patients with sickle cell disease and chronic ongoing pain on an opioid-containing regimen. Our primary endpoint was change in pain as measured by way of a visual analog scale and the Brief Pain Inventory as well as safety.Continue reading