A rising industry of medicinal cannabis products claims to contain specified amounts of 9-tetrahydrocannabinol (THC) and cannabidiol (CBD), although regulation of THC and CBD content varies from state to state and is often poor. In order to investigate the relationship between medical cannabis product usage and exposure to THC and CBD, we measured levels of THC, CBD, and their metabolites in the urine of participants in a clinical study of medical cannabis in Massachusetts.
The Partners Human Research Committee gave its approval for this prospective cohort research. All participants gave written informed permission before to taking part in the study. This research adheres to the STROBE reporting criteria, which stands for Strengthening the Reporting of Observational Studies in Epidemiology.
Adults (aged 18-65 years) who expressed a desire to use cannabis for depression, pain, or sleeplessness were recruited by advertising and evaluated at baseline, as well as at 2, 4, 12, 24, and 48 weeks after beginning to use cannabis for these conditions. It was conducted between June 2017 and August 2020, with results expected in August 2020.
Participants supplied a urine sample at each visit, stated how recently they had used cannabis, and indicated whether their preferred products were THC-dominant, CBD-dominant, or contained nearly equal amounts of CBD and THC. High-performance liquid chromatography with tandem mass spectrometry was used to examine samples collected during visits in which individuals reported consuming products from legal dispensaries during the preceding 48 hours and at least 3 to 4 days per week since the previous visit. 2
With the help of R statistical software version 4.0, we created different models for THC and CBD metabolites. We used Kendall rank correlations for ordinal variables and logistic regressions for nominal variables to create the models (R Project for Statistical Computing). All tests and 95 percent confidence intervals (CIs) were two-sided, and statistical significance was determined as P.05. In the case of logistic regressions, we used the Wald test. The data analysis was carried out between September 2020 and February 2021.
There were 256 urine samples collected from 97 individuals (mean [standard deviation] age 39.6 [14.74] years; 65 women [67.01 percent]) that met the requirements for analysis. At the start of the study, participants were only moderate users (53 percent used less than monthly). The percentage of people who used daily after the baseline ranged from 39 percent to 47 percent, 15 percent to 20 percent for 5 to 6 days per week, and 29 percent to 45 percent for 3 to 4 days per week.
In 220 samples (85.9 percent), at least one cannabis metabolite was found to be present (Table 1). There was no identifiable CBD metabolite in 10 samples (30.3 percent) and 20 samples (37.0 percent) of persons who reported consuming CBD-dominant or CBD-THC products with equal CBD-THC content (Table 2). THC was found in 26 samples (78.8 percent) from persons who reported using CBD-dominant products, according to the study. In samples from persons who reported items with a high concentration of THC or a high concentration of CBD in relation to THC, no THC metabolites were found in 13 samples (10.9 percent) and 19 samples (35.2 percent).
In spite of the fact that vaping was the most often reported form of administration, 27 samples (19.7 percent) from subjects who reported vaping had no detectable cannabinoid at all. Participants who used oral CBD products were more likely to have CBD metabolites identified than those who used vaped (odds ratio [OR], 3.01; 95 percent confidence interval [CI], 1.58-5.74; P.001) or smoked (odds ratio [OR], 2.99; 95 percent confidence interval [CI], 1.38-6.47; P =.005) products. Participants who used oral (OR, 3.56; 95 percent confidence interval, 1.42-8.96; P =.007) and smoked (OR, 3.42; 95 percent confidence interval, 1.26-9.27; P =.007) items were more likely to have THC metabolites identified than those who consumed vaped goods.
Discussion and conclusion
Adults who used medicinal cannabis regularly and lately had higher THC and CBD metabolite amounts in their urine than predicted, which was contrary to expectations. Approximately one-third of samples from participants who reported using CBD-dominant products showed no detectable CBD metabolite, according to the findings. Almost one in every five samples taken from those who vaped cannabis had no detectable cannabinoids.
Using vaping goods, there were no dose-metabolite correlations found. This might imply that vaping devices do not properly heat cannabis products, while devices certified by the United States Food and Drug Administration (US FDA) may provide more consistent cannabinoid exposure than other devices. The variety of medical cannabis products and administration methods creates difficulties in evaluating the effectiveness and safety of the drug.
The study’s methodological limitations include the use of participant-determined dosages, the possibility of self-reporting inaccuracies, the lack of examination of the cannabis products themselves, and individual variances in the rate of absorption and metabolism of the cannabis products. Because the products were obtained through dispensaries in the Greater Boston area, the findings may not be applicable to other places with differing restrictions.
It is similar with the results of a study1 conducted on cannabis products bought in California and Washington, which found that more than half of the goods had been labeled wrongly in both states. These findings suggest that adults who use medical cannabis products may have insufficient or incorrect information about the amount of cannabinoid exposure they can expect from the products they purchase, preventing them from making informed decisions and conducting research into the pharmacologic and therapeutic properties of cannabis products.