As cannabis consumption increases in the United States and abroad, the potential concerns of drug-drug interactions (DDIs) resulting in possible drug toxicity and adverse effects increases. Moreover, the risk of DDIs with psychiatric patients is higher due to their increased consumption of cannabis-related products compared to the average population. A recent systematic review evaluated the effect of CBD and THC on the activity of cytochrome P450 (CYP450) enzymes and the implications of DDIs with psychotropic agents that are CYP substrates. Seven preclinical and clinical studies were included, and results suggested that both CBD and THC inhibit CYP450 enzymes including CYP1A2, CYP3C19, and CYP2B6. Specific interactions included CBD and/or THC with clobazam, bupropion, and citalopram. Psychotropic drugs with a narrow therapeutic index, such as amineptine and tianeptine, are at a particular risk for DDIs. These inhibitory effects vary in magnitude but may decrease the metabolism of psychotropic agents, cause changes in plasma levels of psychotropic medications, and increase adverse effects. However, more clinical research is necessary before these results can be applied in clinical settings, as not enough evidence exists to accurately adjust dosages of psychotropic medication for concurrent cannabis consumption.

Reference:

Smith SA et al. Drug Metabolism Reviews 2024; Online ahead of print. Abstract