Ms. L. is a 70-year-old woman with a history of atrial fibrillation and hypertension who recently noticed that more and more of her peers have started experimenting with cannabis to treat a range of chronic symptoms, often taking advantage of “Senior Citizen Discounts” at local dispensaries. She had no experience with cannabis, but was increasingly curious about it, given her long-standing issues with insomnia. But Ms. L. did not feel comfortable discussing her interest in cannabis with her healthcare provider and did not bring it up during her last routine medical visit.
Finally, she decided to ask her adult son for some of the THC gummies he occasionally uses recreationally. She took an unknown dose of a “gummy” in the evening, and after 15 minutes in which she felt nothing, she took another dose. An hour later, she began feeling intense palpitations, anxiousness and dizziness, and asked her son to take her to the emergency department.
As interest in cannabis among older adults to treat a range of common chronic symptoms has grown, there have been subsequent sharp increases in cannabis use among people ages 65 and older. But, with the growing use of cannabis in this population, there also has been a surge of older adults presenting for acute medical care related to its use. A study found that in California, the number of cannabis-related emergency department visits among people ages 65 and older increased from 366 visits in 2005 (a rate of 20.7 per 100,000 ED visits) to 12,167 (a rate of 395 per 100,000 visits) in 2019. A recent study found that in Canada, cannabis legalization was associated with increased emergency department visits by older adults for cannabis poisoning.
While cannabis may have benefits for select conditions commonly experienced by older adults, as with any psychoactive substance, older adults are at increased risk for harm due to physiological changes that occur with aging, the presence of chronic diseases, and accompanying medication use. Acutely, older adults who use cannabis may experience dizziness, lightheadedness, palpitations, heart rate increase, confusion, and impaired attention that could lead to injuries and falls.
There are increasing concerns about the association of cannabis use with adverse cardiovascular outcomes.
This risk can be compounded with the use of other psychoactive substances, including alcohol or prescription drugs with psychoactive properties (e.g., medications for sleep, depression, or pain). Cannabis also can exacerbate existing chronic diseases, especially cardiovascular or pulmonary diseases, and there are a range of potential drug interactions that can lead to adverse effects.
Additionally, cannabis use disorder, and other related psychiatric conditions are increasing and must be considered for all people who use cannabis. Despite these potential risks, the perception of cannabis as risky has sharply declined among older adults.
There are several things to consider for older adults who are newly curious about cannabis use. First, it is essential to discuss cannabis use with their healthcare providers to review the potential benefits and risks and dosing and route of use (e.g., inhaling, ingesting, topical), given their current health status.
Second, the content of delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis, in cannabis products has increased over the past several decades. Therefore, cannabis products used now have a much stronger potency than they did previously. This means that older adults who may have tried cannabis decades ago may not be accustomed to the THC content in available cannabis products and should be cautious when using cannabis.
Next, as with most medications for older adults, starting at the lowest dose and gradually increasing slowly to assess benefits and potential side effects is a good approach. A proposed standard dose of THC in research is 5 mg, but older adults should consider starting at a much lower dose, such as 1 mg or 2.5 mg.
Older adults also should be counseled on the different routes of cannabis and how they may experience its effects differently. For example, while smoking or inhaling cannabis, which is generally not advised, the onset of psychoactive effects can occur within 15 minutes and last up to a few hours. Meanwhile, ingested cannabis often will have a delayed onset and is influenced by a range of factors, including if it is taken after a meal or on an empty stomach. Therefore, edible cannabis can take up to several hours to have an effect and can last up to 12 hours.
Finally, older adults should be counseled not to use other psychoactive substances, including alcohol, while using cannabis.
Returning to Ms. L., her emergency department visit may have been avoided if she had been counseled on cannabis use prior to trying it. If her atrial fibrillation was not well-controlled, it may have been inadvisable for her to try cannabis. There also are increasing concerns about the association of cannabis use with adverse cardiovascular outcomes. And she should have been instructed to pay careful attention to the cannabinoid doses, especially in products containing THC, and to start at the very lowest dose available. Finally, routes of use should be discussed, and how, if using edible cannabis, it may take several hours to feel any effect and to avoid repeat dosing until she waits long enough to feel its effect.
Some helpful resources for cannabis use by older adults include a guide from the Canadian Centre on Substance Use and Addiction, and the American Medical Association Update on cannabis side effects for older patients with an interview by Dr. Alison Moore.
Benjamin H. Han, MD, MPH, is a geriatrician, addiction medicine physician and clinician-researcher in the Division of Geriatrics, Gerontology, and Palliative Care in the Department of Medicine at UC San Diego. Alison Moore, MD, MPH, FACP, AGSF, is a professor and chief of the Division of Geriatrics, Gerontology, and Palliative Care and director of the Sam and Rose Stein Institute for Research on Aging and the Center for Healthy Aging, and she holds the Larry L. Hillblom Chair in Geriatric Medicine at UC San Diego.
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