Meta-analysis: Incidence Rate Difference of Adverse Events from Canabinoids in Middle-Aged and Older Adults
25 Dec, 2024 | 12:19h | UTCBackground: Growing evidence suggests that cannabinoid-based medicines (CBMs) are increasingly prescribed to individuals aged 50 years and above for various clinical conditions. While these agents may offer therapeutic benefits, questions remain about the incidence of adverse events (AEs), particularly in older adults with multiple comorbidities. This systematic review and meta-analysis aims to quantify the incidence rate difference (IRD) of AEs and determine whether weekly doses of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are associated with any dose-dependent increase in risk.
Objective: To evaluate whether adults aged ≥50 years exposed to CBMs, including THC-alone formulations and THC combined with CBD, experience a higher incidence of AEs than controls, and to assess how variations in weekly THC and CBD doses might affect AE rates.
Methods: Researchers searched MEDLINE, PubMed, EMBASE, CINAHL, PsychInfo, Cochrane Library, and ClinicalTrials.gov from January 1, 1990, to June 12, 2023. Randomized clinical trials involving middle-aged and older adults (mean age ≥50 years) using medicinal CBMs for all indications were included. Data on common and serious AEs, withdrawals, and deaths were extracted and pooled using a random-effects model. Further meta-regression analyses examined THC and CBD weekly doses as predictors of AEs in THC-only and THC:CBD trials.
Results: Fifty-eight randomized clinical trials (n=6611) met inclusion criteria, with 3450 participants receiving CBMs. Compared to controls, individuals on THC-alone experienced significantly higher incidence of dizziness, somnolence, impaired coordination, dissociative symptoms, and dry mouth, often in a dose-dependent manner. Similarly, THC:CBD combinations increased nausea, vomiting, fatigue, dizziness, and disorientation. The incidence of serious AEs, withdrawals, or mortality did not differ significantly between CBM and control groups, although neurological or psychiatric side effects were more pronounced with higher THC doses.
Conclusions: THC-containing CBMs can provoke dose-related gastrointestinal, neurological, and psychiatric adverse events, posing additional risks in older adults susceptible to falls and cognitive disturbances. However, the meta-analysis found no significant increases in serious AEs or deaths. Clinicians should weigh potential benefits against the likelihood of common side effects, especially when prescribing higher THC doses or combining cannabinoids with other medications frequently used by older patients.
Implications for Practice:
- Physicians should exercise caution when initiating or escalating THC-based therapies in middle-aged and older adults, monitoring for neurological or psychiatric AEs.
- Using lower THC doses, titrating gradually, and adding CBD may mitigate some side effects.
- Though severe AEs are uncommon, vigilance is warranted in individuals with complex medication regimens.
Study Strengths and Limitations:
- Strength: This review merges diverse clinical conditions and provides a comprehensive assessment of THC vs. THC:CBD. Its large pooled population allows for more precise IRD estimates.
- Limitation: Short treatment durations in many trials limit understanding of long-term toxicity, and some studies lacked rigorous reporting of randomization and outcome measures, potentially introducing bias.
Future Research:
- Longer-duration trials focused on older populations are needed to clarify chronic safety profiles.
- Studies exploring drug-drug interactions between CBMs and medications commonly prescribed to older adults will further elucidate real-world tolerability.
Reference: Velayudhan L, Pisani S, Dugonjic M, McGoohan K, Bhattacharyya S. Adverse events caused by cannabinoids in middle aged and older adults for all indications: a meta-analysis of incidence rate difference. Age and Ageing. 2024;53(11):afae261. DOI: https://doi.org/10.1093/ageing/afae261