Current state of knowledge on medical cannabis use and risk for infections: A practical guide for clinicians

Patients and clinicians broadly support medical cannabis, but acknowledge limited understanding of products, efficacy, and safety. Here, we review cannabis products, regulatory issues, microbial contamination of cannabis, and infections linked to cannabis. In the U.S., cannabis is regulated by a patchwork of federal and state laws. Three pharmaceutical-grade cannabinoids are U.S. FDA-approved, and non-FDA-approved medical cannabis products are legal in 40 states. There are no uniform standards for testing products for microbes or validated safety thresholds from state-to-state. Reports of cannabis-associated fungal and bacterial infections have been published. However, only a single case report used genome sequencing to conclusively link a disease-causing fungus (Cryptococcus neoformans) to cannabis consumed by the patient. Therefore, infections can clearly complicate cannabis use, but extent of risk and specific risk factors are unknown. There is urgent need for harmonized cannabis regulation, standardized product testing and safety criteria, and clinical and translational research on infectious risks.