A recent clinical trial raises questions about the safety of widely consumed CBD capsules, gummies, edibles, oils and lotions that are omnipresent in the United States and many other countries. But pioneer cannabis clinician Bonni Goldstein, MD, cautions patients and physicians not to overstate the findings of the new FDA study, which was published in JAMA Internal Medicine. Below is a summary of the trial results followed by comments from Dr. Goldstein, the CEO and co-founder of GoldsteinWellness.com, a free medical cannabis educational platform for licensed healthcare clinicians, and Medical Director of Canna-Centers in California.
Last year, scientists from the FDA’s Division of Applied Regulatory Science carried out a randomized double-blind placebo-controlled trial to assess how “low-dose CBD” affects liver function in a group of healthy middle-aged men and women. The results of the trial were recently published by JAMA Internal Medicine.
Over the course of four weeks, 201 volunteers received either 5 mg per kilogram of body weight (approximately 2.3 mg per pound or the equivalent of 350 mg for a 154-pound individual) of oral CBD isolate, or a placebo for comparison. The CBD dose administered to participants is described in the report as “a typical amount that might be used by consumers.”
While the vast majority of people in the trial were unaffected, five percent showed greatly elevated levels of the liver enzyme aminotransferase, a known marker of liver cell damage or inflammation. Women appeared to be more vulnerable than men. Those who experienced the most serious liver problems also developed signs of an immune condition called eosinophilia, which occurs when the body produces an excess of a type of white blood cell called eosinophils. In all cases, the liver enzyme levels returned to normal within one or two weeks of stopping CBD.
Elevated levels of liver enzymes were among the leading causes of withdrawal of young epilepsy patients from previous clinical trials involving high doses of Epidiolex, a pharmaceutical CBD isolate. Raised liver enzymes were observed in 14% of participants, who were concurrently taking other anti-epileptic medications, which could have contributed to the adverse liver effects.