May 31, 2021
Caroline A. MacCallum, Lindsay A. Lo, Michael Boivin
Open Access Published


• A safety-focused approach is necessary in each step of patient's cannabis journey. • Prior to initiation, screen for precautions, contraindications & drug interactions. • Patient risk factors guides choice of chemovar and route of administration. • Initiate cannabis using a low dose, slow titration method. • Set monitoring frequency, and adjust for adverse events or medication changes.


Medical cannabis use is increasing worldwide. Clinicians are commonly asked by patients to provide guidance on its safety and efficacy. Although there has been an increase in research on the role of medical cannabis for a number of different conditions, we found that there was a paucity of clear safety guidance on its use. We aim to address this issue by answering two pertinent clinician safety questions:
1 Can medical cannabis be safely used in this patient?
2. What strategies can be used to ensure that any harms from medical cannabis are mitigated?
To address these questions, we reviewed available evidence and provided expert clinical opinion to summarize the fundamental components for evaluating medical cannabis safety and strategies to reduce risk from its use. Our review resulted in a safety-focused framework for medical cannabis initiation and utilization. We provide clear recommendations for patients being considered for cannabis (e.g. precautions, contraindications and drug interactions). Risk mitigation strategies such as appropriate chemovar (strain) selection, routes of administration, and dosing are reviewed. As with any other pharmacotherapy, we review the key components of monitoring and address potential issues that may arise while using medical cannabis. We propose a structured assessment and monitoring strategy that can be used by clinicians recommending cannabis (CRC) to guide patients through each step of their cannabis journey. This framework can be used to ensure that medical cannabis utilization is associated with the lowest possible risk to the patient.


Medical cannabis
Cannabinoid based medicines, CBM
Tetrahydrocannabinol, THC
Cannabidiol, CBD
Adverse Events, AE
Adverse Drug Reaction, ADR
Side Effects
Drug Interactions, DI