Medical cannabis use in older patients: Update on medical knowledge

Medical Cannabis Use and Its Impact on Health Among Older Adults: Recent Research Findings and Future Directions

Purpose of Review

With the rapidly changing landscape of state level legalization of cannabis, older adults have become one of the fastest growing populations seeking medical cannabis (MC). However, research evidence on the risks and benefits of MC use in this population remains limited. This review aims to synthesize recent literature on the impacts of MC use in older adults and identify critical knowledge gaps to be addressed in future research.

Recent Findings

Recent literature showed that older adults often face financial and/or educational barriers and stigma associated with MC access. Emerging data showed that MC may have therapeutic effects on symptoms of conditions such as chronic pain, insomnia, anxiety/depression, dementia, nausea, and vomiting. However, available evidence is inconsistent and tends to rely on self-report and uncontrolled studies. While some adverse events associated with MC use were reported, it is generally well tolerated in older adults. Neurocognitive and psychological consequences and cardiovascular risks have been reported but again only in limited studies with inconsistent findings.

Summary

There is a need for more systematic and rigorous research on MC in older adults to determine its safety and efficacy. Research on dosing procedures and product characteristics, as well as how these may impact health outcomes, is crucial. More consistent evidence is needed to inform policy changes and patient/physician education to minimize potential risks and optimize benefits among older adults seeking MC as an alternative treatment.

Long-Term Recreational Cannabis Use Is Associated With Lower Executive Function and Processing Speed in a Pilot Sample of Older Adults

More older adults are using cannabis for recreational and/or medical purposes, but most studies examining cognitive function and cannabis use do not include older adults. The current small pilot study sought to compare cognitive function and emotional functioning among adults age 60 and older who were regular, primarily recreational cannabis users (n = 28) and nonusers (n = 10). A bimodal distribution was observed among cannabis users such that they had either initiated regular use more recently ("short-term" users; ≤7 years, n = 13) or earlier in life ("long-term" users; ≥19 years, n = 15). Nonusers, short-term, and long-term users were not different in depression, anxiety, or emotion regulation, or alcohol use. Nonusers scored significantly higher than long-term users in executive function. Short-term users scored significantly higher than long-term users in executive function, processing speed, and general cognition. Additionally, greater recent cannabis use frequency was negatively associated with working memory. The current findings suggest that short-term recreational cannabis use does not result in differences in cognitive performance compared to nonusers, which may indicate that short-term use is relatively benign in older adults. However, longer duration of use is associated with poorer processing speed and executive functioning, and more recent cannabis use is associated with poorer working memory, which may impact older adults' overall cognitive functioning.

Medical Cannabis Use Among Older Adults in Canada: Self-Reported Data on Types and Amount Used, and Perceived Effects

Background

Medical cannabis use is growing among older adults. In this retrospective study, we aimed to assess the characteristics of older medical cannabis users including the indications, type and amount of cannabis used, perceived changes in symptoms after cannabis use, change in dose of concurrent medications, and adverse effects.

Methods

Data were collected between October 2014 and October 2020 from patients who were consulting the Canada-wide network of clinics of a medical cannabis provider and who were willing to answer questionnaires based on their medical status. The current study included older adults (≥ 65 years) who completed questionnaires at intake and first follow-up visits. Data were summarized with descriptive statistics, which were compared between men and women with t tests or chi-squared tests. Tests of proportions assessed categorical responses for perceived effects after cannabis use. Logistic regression was used to assess trends in cannabis usage.

Results

Data included that from 9766 older adult users at intake (mean ± SD age = 73.2 ± 6.8 years, females = 60.0%), among whom 4673 (females = 61.4%) returned for follow-up after 90.6 ± 58 days. The most common primary indication for which medical cannabis was sought was pain (67.7%), which was more common in women, whereas oncological and neurological conditions were more common in men. At follow-up, cannabis oil was used by 81.0% of older adults, among whom compositions containing only or mostly cannabidiol (CBD) had been used by 83.6%. Adverse effects reported by older adults at the follow-up visit included dry mouth (12.8%), drowsiness (8.6%), and dizziness (4.0%). The majority of older adults reported improvements in pain (72.7%, z = 1482.6, p < 0.0001, compared to worsening or no change), sleep (64.5%, z = 549.4, p < 0.0001), and mood (52.8%, z = 16.4, p < 0.0001), with 35.6% reporting use of a reduced dose of opioids and 19.9% a reduced dose of benzodiazepines.

Interpretation

Among older adults, medical cannabis is used more often by women, with CBD-containing cannabis oils being the most commonly used. Users reported improved pain, sleep, and mood symptoms at follow-up after cannabis use. This study describes the patterns of use of medical cannabis by older adults and highlights the need for research to determine appropriate indications, precise doses of active ingredients, and short- and long-term outcomes among older adults.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40266-021-00913-y.

Safety and Tolerability of Natural and Synthetic Cannabinoids in Older Adults: A Systematic Review and Meta-Analysis of Open-Label Trials and Observational Studies

BACKGROUND AND OBJECTIVE

Although cannabinoid-based medications are increasingly used by older adults, their safety and tolerability in this age group remain unclear. The purpose of this systematic review was to examine the safety and tolerability of cannabinoid-based medications by conducting a meta-analysis of open-label observational studies of cannabinoid-based medications for all indications in individuals with a mean age of ≥50 years.

METHODS

A systematic search was conducted on PubMed, PsycINFO, MEDLINE, EMBASE and CINHAL. Study quality was assessed using an adapted version of the Grading of Recommendations Assessment, Development and Evaluation criteria and Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed. We included studies that (a) were published from 1990 onwards; (b) included older adults (mean age ≥50 years); and (c) provided data on the safety and tolerability of medical cannabinoids. Data were pooled using a random-effects approach. Risk of adverse events, serious adverse events and withdrawals was computed as the incidence rate (IR). Separate analyses were conducted by the cannabinoid-based medication used, for delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD) and a combination of THC and CBD (THC:CBD).

RESULTS

Thirty-eight studies were identified (THC = 23; CBD = 6; THC:CBD = 9; N = 2341, mean age: 63.19 ± 8.08 years, men: 53.86%). THC had a very low incidence of all-cause and treatment-related adverse events (IR: 122.18, 95% confidence interval [CI] 38.23-253.56; IR: 84.76, 95% CI 0.13-326.01, respectively) and negligible serious adverse events (IR = 0). Similar IRs for CBD (all cause, IR: 111.91, 95% CI 1.24-495.93; treatment related, IR: 1.76, 95% CI 4.63-23.05) and no serious adverse events (IR = 0). CBD was not associated with a risk of treatment-related withdrawals. THC had a low risk of all-cause and treatment-related withdrawals (IR: 25.18, 95% CI 12.35-42.52; IR: 7.83, 95% CI 3.26-14.38, respectively). The THC:CBD treatment had a low risk of all-cause and treatment-related adverse events (IR: 100.72, 95% CI 0.25-383.00; IR: 55.38, 95% CI 8.61-142.80, respectively), but reported a risk of all-cause and treatment-related serious adverse events (IR: 21.32, 95% CI 0.18-93.26; IR: 3.71, 95% CI 0.21-11.56, respectively), and all-cause and treatment-related withdrawals (IR: 78.63, 95% CI 17.43-183.90; IR: 34.31, 95% CI 6.09-85.52, respectively). Significant heterogeneity (I² >55%) was present in most analyses.

CONCLUSIONS

Although cannabinoid-based medications were generally safe and acceptable to adults aged over 50 years, these estimates are limited by the lack of a control condition and considerable heterogeneity. Nevertheless, they complement and are consistent with comparable evidence from randomised controlled trials.

Fibromyalgia in Older Individuals

Fibromyalgia (FM) is a condition of chronic widespread pain (CWP) that can occur throughout the life cycle and is likely underrecognized in older patients. FM is associated with considerable suffering and reduction in quality of life and may occur as a unique condition, but in older patients is most likely to be associated with another medical illness. Understood mechanistically to be a sensitization of the nervous system, recently identified as nociplastic pain, FM is accepted as a valid medical illness that requires a positive diagnosis and directed treatments. The cornerstone of treatments for FM are nonpharmacologic interventions, with the understanding that medications provide only modest benefit for most patients, and with particular concern about adverse effects in older patients. If FM is not recognized, treatments may be misdirected to the other medical condition, with failure to address FM symptoms, leading to overall poor outcome. In contrast, new complaints in older patients should not immediately be attributed to FM, and physicians should be vigilant to ensure that onset of a new illness is not ignored. As FM is most often a lifelong condition, patients should be encouraged to identify their own personal strategies that can attenuate symptoms, especially when symptoms flare. Continued life participation should be the outcome goal.

Safety and tolerability of natural and synthetic cannabinoids in adults aged over 50 years: A systematic review and meta-analysis

BACKGROUND

Cannabinoid-based medicines (CBMs) are being used widely in the elderly. However, their safety and tolerability in older adults remains unclear. We aimed to conduct a systematic review and meta-analysis of safety and tolerability of CBMs in adults of age ≥50 years.

METHODS AND FINDINGS

A systematic search was performed using MEDLINE, PubMed, EMBASE, CINAHL PsychInfo, Cochrane Library, and ClinicalTrials.gov (1 January 1990 to 3 October 2020). Randomised clinical trials (RCTs) of CBMs in those with mean age of ≥50 years for all indications, evaluating the safety/tolerability of CBMs where adverse events have been quantified, were included. Study quality was assessed using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) criteria and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. Two reviewers conducted all review stages independently. Where possible, data were pooled using random-effects meta-analysis. Effect sizes were calculated as incident rate ratio (IRR) for outcome data such as adverse events (AEs), serious AEs (SAEs), and death and risk ratio (RR) for withdrawal from study and reported separately for studies using tetrahydrocannabinol (THC), THC:cannabidiol (CBD) combination, and CBD. A total of 46 RCTs were identified as suitable for inclusion of which 31 (67%) were conducted in the United Kingdom and Europe. There were 6,216 patients (mean age 58.6 ± 7.5 years; 51% male) included in the analysis, with 3,469 receiving CBMs. Compared with controls, delta-9-tetrahydrocannabinol (THC)-containing CBMs significantly increased the incidence of all-cause and treatment-related AEs: THC alone (IRR: 1.42 [95% CI, 1.12 to 1.78]) and (IRR: 1.60 [95% CI, 1.26 to 2.04]); THC:CBD combination (IRR: 1.58 [95% CI,1.26 to 1.98]) and (IRR: 1.70 [95% CI,1.24 to 2.33]), respectively. IRRs of SAEs and deaths were not significantly greater under CBMs containing THC with or without CBD. THC:CBD combination (RR: 1.40 [95% CI, 1.08 to 1.80]) but not THC alone (RR: 1.18 [95% CI, 0.89 to 1.57]) significantly increased risk of AE-related withdrawals. CBD alone did not increase the incidence of all-cause AEs (IRR: 1.02 [95% CI, 0.90 to 1.16]) or other outcomes as per qualitative synthesis. AE-related withdrawals were significantly associated with THC dose in THC only [QM (df = 1) = 4.696, p = 0.03] and THC:CBD combination treatment ([QM (df = 1) = 4.554, p = 0.033]. THC-containing CBMs significantly increased incidence of dry mouth, dizziness/light-headedness, and somnolence/drowsiness. Study limitations include inability to fully exclude data from those <50 years of age in our primary analyses as well as limitations related to weaknesses in the included trials particularly incomplete reporting of outcomes and heterogeneity in included studies.

CONCLUSIONS

This pooled analysis, using data from RCTs with mean participant age ≥50 years, suggests that although THC-containing CBMs are associated with side effects, CBMs in general are safe and acceptable in older adults. However, THC:CBD combinations may be less acceptable in the dose ranges used and their tolerability may be different in adults over 65 or 75 years of age.

Cannabis use and sleep: Expectations, outcomes, and the role of age

STUDY OBJECTIVES

Determine relationship between cannabis use with 1) expectations of cannabis being a sleep aid, 2) subjective sleep outcomes, and 3) the influence of age on these relationships.

METHODS

In 152 moderate cannabis users with a wide age range (67% female, mean age = 31.45, SD = 12.96, age range = 21-70; mean days of cannabis use in prior two weeks = 5.54, SD = 5.25) we examined the influence of cannabis use history and behaviors on expectations of cannabis being a sleep aid and sleep outcomes via the Pittsburgh Sleep Quality Index (PSQI). Moderation analysis examined the role of age in the relationship between cannabis use and sleep outcomes.

RESULTS

Endorsing current cannabis use and more days of cannabis use were associated with increased expectations that cannabis use improves sleep (all β > 0.03, p < 0.04). Frequency of recent use and reported average THC or CBD concentration were largely not associated with sleep outcomes. However, endorsing current cannabis use was associated with worse subjective sleep quality (β = 1.34, p = 0.02) and increased frequency of consuming edibles was associated with worse subjective sleep efficiency (β = 0.03, p = 0.04), lower sleep duration (β = 0.03, p = 0.01), and higher global PSQI scores (worse overall sleep) (β = 0.10, p = 0.01). Additionally, age had a moderating influence on the relationship between increased self-reported concentration of CBD and both better sleep duration and sleep quality (both p < 0.03). While the main effects of cannabis use on sleep outcomes did not survive multiple comparisons correction test (all p adj > 0.34), the adjusted p values for the main effects of cannabis behaviors/history on expectations of cannabis as a sleep aid (p adj = 0.07-0.09) and the main effects of CBD concentration on sleep duration (p adj = 0.08), as well as the interaction terms of CBD and age for that model (p adj = 0.07), were trending.

CONCLUSION

Cannabis users have increased expectations of cannabis being a sleep aid, but few associations existed between cannabis use and sleep outcomes. The two exceptions were endorsing any cannabis use and frequency of edible use. Additionally, age may be an important moderator of the potential positive influence CBD concentration can have on sleep.

Development of Gas-Chromatographic Method for Simultaneous Determination of Cannabinoids and Terpenes in Hemp

An original gas chromatographic method has been developed for simultaneous determination of major terpenes and cannabinoids in plant samples and their extracts. The main issues to be addressed were the large differences in polarity and volatility between both groups of analytes, but also the need for an exhaustive decarboxylation of cannabinoid acidic forms. Sample preparation was minimised, also by avoiding any analyte derivatisation. Acetone was found to be the most appropriate extraction solvent. Successful chromatographic separation was achieved by using a medium polarity column. Limits of detection ranged from 120 to 260 ng/mL for terpenes and from 660 to 860 ng/mL for cannabinoids. Parallel testing proved the results for cannabinoids are comparable to those obtained from established HPLC methods. Despite very large differences in concentrations between both analyte groups, a linear range between 1 and 100 µg/mL for terpenes and between 10 and 1500 µg/mL for cannabinoids was determined.

Cannabinoids in the Older Person: A Literature Review

INTRODUCTION

Medical cannabinoids have received significant mainstream media attention in recent times due to an evolving political and clinical landscape. Whilst the efficacy of cannabinoids in the treatment of some childhood epilepsy syndromes is increasingly recognized, medical cannabinoids may also have potential clinical roles in the treatment of older adults. Prescribing restrictions for medical cannabinoids in certain jurisdictions (including the UK) has recently been relaxed. However, few geriatricians have the detailed knowledge or awareness of the potential risks or rewards of utilizing cannabinoids in the older person; even fewer geriatricians have direct experience of using these drugs in their own clinical practice. Older persons are more likely to suffer from medical illness representing potential indications for medical cannabinoids (e.g., pain); equally they may be more vulnerable to any adverse effects.

AIM

This narrative literature review aims to provide a brief introduction for the geriatrician to the potential indications, evidence-base, contra-indications and side effects of medical cannabinoids in older people.

METHODS

A search was conducted of CENTRAL, Medline, Embase, CINAHL and psycINFO, Cochrane and Web of Science databases. Reference lists were hand searched. Abstracts and titles were screened, followed by a full text reading of relevant articles.

RESULTS

35 studies were identified as relevant for this narrative review.

CONCLUSIONS

Cannabinoids demonstrate some efficacy in the treatment of pain and chemotherapy-related nausea; limited data suggest potential benefits in the treatment of spasticity and anxiety. Risks of cannabinoids in older patients appear to be moderate, and their frequency comparable to other analgesic drug classes. However, the quality of research is weak, and few older patients have been enrolled in cannabinoid studies. Dedicated research is needed to determine the efficiency and safety of cannabinoids in older patients.

Adverse events following cannabis for medical use in Tuscany: An analysis of the Italian Phytovigilance database

AIMS

Despite a significant increase in using cannabis for medical purposes, current evidence on its safety in real-world clinical practice is still poorly characterised. By a case-by-case analysis of spontaneous reports of suspected adverse events (AEs) collected in Tuscany within the Italian Phytovigilance database, the aim of the present study was to describe AEs occurred in patients exposed to medical cannabis.

METHODS

We evaluated all reports of cannabis-related suspected AEs collected within the Phytovigilance database up to December 2018. Information regarding cannabis therapy, patient's demographic and clinical characteristics, concomitant medications, AE description according to the Medical Dictionary for Regulatory Activities (MedDRA) classification, AE seriousness and AE outcome, were collected. The causality assessment was performed following World Health Organisation-Uppsala Monitoring Centre criteria.

RESULTS

Fifty-three cannabis-related AE reports were analysed. The majority of patients were females (77.3%), with a mean age of 61.9 years. Thirty-nine (73.6%) cases were defined as nonserious and the majority of them (86.9%) showed a complete resolution or improvement. Forty-six (86.8%) cases were judged as probably related to cannabis consumption. The most frequently reported system organ class was psychiatric and nervous system disorders, and a potential drug-drug interaction was present in 16 cases.

CONCLUSION

Cannabis was generally well tolerated and the majority of AEs were mild and transient. Our analysis highlighted important safety issues for clinical practice, in particular the need for an accurate prescription monitoring during the titration phase, particularly in the presence of concomitant medications.