Fatemeh Mehrabi
University of Florida
Co-Authors: Sebastian Jugl1, Amie J Goodin1, Earl J Morris1
1University of Florida
Background: The legalization of medical cannabis (MC) in the United States has resulted in a significant increase in its use among adults over 65 years old in the past two decades. Despite its growing popularity, few studies have assessed the potential for drug-drug interactions (DDIs) involving MC and potentially inappropriate medications (PIMs) in older adults (MC-PIM DDIs). There is a need for an updated review of MC-PIM DDIs given the recently updated 2023 Beers Criteria and advances in MC PK/PD research.
Objective: This study sought to develop a framework for assessing potential MC-PIM DDIs in older adults, using current PK/PD data.
Methods: PIMs were defined using the 2023 Beers Criteria, and MC-PIM DDIs were systematically assessed using Clinical Pharmacology, FDA package inserts, and literature review. We created a detailed list of PIMs from the Beers Criteria, along with their potential interactions with THC and CBD.
Results: Cannabidiol (CBD) is a substrate of CYP2C19 and CYP3A4; tetrahydrocannabinol (THC) is a substrate of CYP2C9 and CYP3A4. CBD and THC both inhibit CYP2B6, CYP2C9, CYP3A4, CYP2D6. CBD also inhibits CYP1A2, CYP1B1, and CYP2C19; while THC induces CYP1A2. We identified 6 PIM categories with potential for MC-PIM DDIs, including antihistamines, cardiovascular/antithrombotics, central nervous system, endocrine, gastrointestinal, and pain.
Conclusions: The following clinical suggestions should be emphasized when prescribing MC with PIMs listed in this framework: a) Conduct medication reviews to identify potential DDIs and adverse drug effects; b) Assess the current evidence for MC and evaluate its effectiveness in relevant conditions; c) Evaluate fall risk, neuropsychiatric conditions, and cardiovascular disease; d) Titrate doses of THC/CBD gradually; e) Deprescribe MC and PIMs when possible.