Adverse events associated with medical cannabis reported within a centralized call center

Introduction The use of medical cannabis products is expanding, yet real-world data on associated adverse events (AEs) remain limited. Controlled trials often exclude diverse patient populations and product types, making post-marketing surveillance essential to understanding cannabinoid safety. Objective The aim of this study is to characterize AEs reported by patients enrolled in the Minnesota Medical Cannabis Program and explore associations between AE severity, cannabinoid doses, and product types. Materials and methods This was a retrospective analysis of AEs reported between 2015 and 2021 by individuals receiving products from a single licensed manufacturer. Demographic data, qualifying condition, cannabis formulation, and daily purified cannabidiol (CBD)/delta-9-tetrahydrocannabinol (THC) doses were collected. AEs were classified by severity and analyzed in relation to cannabinoid content and product formulation using non-parametric Mann–Whitney U tests ( p < 0.05). Results A total of 237 calls were received from 225 individuals reporting 692 symptoms. Most calls were from medical cannabis consumers (79.3%) and were predominantly classified as minor in severity (71.7%). Most AEs were associated with THC-dominant products (39.8%), and capsule formulations (36.8% of the overall products) were most commonly implicated. Among individuals with dose data, those with moderate AEs were associated with significantly higher daily THC doses than those with minor AEs ( p < 0.05). Treatment discontinuation occurred in 32.5% of cases following AE reporting. Conclusion Although AEs were infrequently reported, they were often clinically meaningful and led to treatment discontinuation. The voluntary nature of reporting likely underestimates the actual AE burden, capturing only more severe or bothersome events. These findings underscore the need for enhanced pharmacovigilance systems and further research into the long-term safety and public health implications of cannabinoid therapies, especially among medically complex patients.