Personalized medicine: applications of medical cannabis in geriatrics

By Flor Ortiz. Veterinary Zootechnician (FMVZ-UNAM), medical researcher of the medicinal use of cannabis in veterinary and human medicine.

Seniors are special needs patients, certainly a group that can benefit from medical cannabis or marijuana. Cannabis can help treat seniors with fewer risks than many current medications.

Currently, medical cannabis or marijuana is rapidly entering the pharmacological arsenal, including its use in elderly patients. Due to the unique characteristics of the geriatric population, there is a need for safe medications to address their ailments.

Medical cannabis has shown promise in treating many conditions of concern to elderly patients, so we will review the current therapeutic potential of cannabis in this population. [8]

Geriatric population in Mexico

Based on the National Survey of Demographic Dynamics (ENADID) 2018, 15.4 million people aged 60 years or older reside in the country, of which 1.7 million live alone. Almost half of older adults (47.9 %) live in single family households, and 11.4 % live alone. Seven out of ten older adults living alone have some type of disability or limitation.

In the country, 85.4% of elderly people living alone are affiliated with a health care institution, and most of them seek medical attention when they have a health problem. In fact, 9 out of every 100 are seen in a pharmacy office.

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The natural deterioration of body functions due to aging makes it difficult to perform activities of daily living and is manifested mainly by the gradual loss of physical independence. Older adults are at greater risk of suffering some kind of disability or limitation and, therefore, needing some kind of help or assistance. In the case of those who live alone, it is very likely that they do not have any immediate or nearby help to perform their daily activities or in some cases, require specific care. [7]

Epidemiological data show that the older population constitutes a growing segment of medical cannabis users, ranging from approximately 7% to 33% depending on the country. [1] In a recent study in Israel, it was found that of 279 cancer patients receiving medical cannabis, 50% were aged 60 years or older, which gives reason to focus on this segment of the population as potential patients for medical cannabis. [8]

Cannabis as an alternative to other drugs

Managing different symptoms in older adults can be challenging, as conventional medications can cause side effects that worsen quality of life or cause other symptoms. To mention a few examples: opioids can increase the risk of constipation, confusion, falls and fractures; benzodiazepines also increase the risk of fractures and soft tissue injuries; dopamine antagonists can increase the risk of death in older adults with dementia.

Because of these problems with the current arsenal of symptomatic interventions and the side effects of commonly used drugs, cannabinoids may offer an alternative to help older adults. [4] Many of the symptoms in these patients may not be adequately controlled by conventional pharmacologic treatments, either because of suboptimal effects of pharmacotherapies or unacceptable adverse effects of pharmacotherapies. [11]

Areas of application of cannabis in geriatrics

Cannabis preparations contain numerous cannabinoids, including delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as their main components. These cannabinoids act on an endogenous cannabinoid system. [12] Treatment with medical cannabis can provide help to older adults in areas such as: decreased pain, improved sleep quality, motor changes such as decreased tremors or spasticity, and improvement in mood disturbances and agitation. [11]

Substantial evidence suggests that the activity of the endocannabinoid system (ECS) decreases during aging, as the amount of receptors, endocannabinoids and proteins decreases with age. Because of this, restoration of SEC signaling in elderly individuals could be an effective strategy to treat age-related cognitive deficits. [3]

The main symptoms or diseases for which cannabis has been used to help older adults are as follows: [1,5,8,11,12]

Joint diseases.
Parkinson's disease.
Chronic pain.
Dementia and Alzheimer's disease.
Neurological and psychiatric diseases.
Sleep disturbances.
Nausea and vomiting (associated with chemotherapy).
Respiratory diseases.
Mood disorders and agitation.

The most common forms of use in this age group are: topical application, spraying or spraying under the tongue, followed by ingestion of capsules, vaping and finally edibles. [6]

Considerations for the use and application of cannabinoid medicine in geriatrics.

The efficacy and safety data established in adult studies cannot simply be extrapolated to the group of older patients. Additionally, the high prevalence of comorbidity and polypharmacy related to geriatric patients further complicates pharmacological treatment in this population. Therefore, it is highly relevant to study the effects of cannabinoids in older patients separately before recommending widespread use. [12]

It is important to take the following considerations into account:

Assess the psychiatric and substance abuse history in any patient for whom cannabis treatment is to be recommended, particularly if any formulation containing THC is to be prescribed.
Assess for cognitive impairment before recommending medical cannabis, as the risk of cognitive impairment increases with age.
Cannabis (especially THC) can impair driving ability, so people should be warned not to drive for at least 6 hours after vaporizing or smoking and 9 hours after consuming edibles.

Marijuana abuse has not historically been a major concern in older adults; however, it is possible that it may be related to increased substance abuse (of all varieties) in older adults. [4]

Safety and adverse effects in geriatric patients

Determining the safety of treatment and dosage is a challenge for physicians. Therefore, it is advised to proceed cautiously with dosing following the "start low and go slow" rule, until a dose is reached that has an effect on symptoms.

When starting a cannabinoid treatment, slow dose titration is required to avoid adverse effects, including falls and orthostatic hypotension. [9] Additionally, patient follow-up is recommended to monitor the patient for lack of response to treatment, complications or abuse, misuse, or diversion. [2]

Common adverse effects experienced by patients due to cannabis use include: dizziness, euphoria, drowsiness, confusion and disorientation. These events are particularly important in the elderly population, as they may suffer from conditions such as dementia, frequent falls, mobility problems, hearing or visual impairment. [1]

Acute toxicity and overdose are also possible with medical marijuana use, especially in patients who have not been evaluated by a physician and do not follow a dosing regimen. Self-use without medical indications could lead to a variety of undesirable effects. In addition, there are pharmacokinetic differences depending on the route of administration. [10]

Oral products can take up to six hours after ingestion to be absorbed, which may lead users to ingest an additional dose before clinical effects have fully occurred, increasing the potential for accidental overdose. [10]

The most commonly reported clinical effect is respiratory depression, but cardiovascular and neurological toxicity has also been reported. The increased availability of edible formulations through dispensaries has led to more reports of ingestions beyond the recommended dose. Consumption of large single doses of THC can trigger an episode of acute psychosis.

Drug interactions to be taken into account

There is a high suspicion of drug interaction because cannabinoids are metabolized by CYP3A4, CYP2C9, and CYP2C19 enzymes, which are involved in the metabolism of numerous medications used by older adults. Because of the above, interactions are possible, so the full list of medications the patient is taking must be known before cannabinoids can be prescribed.

Conclusions

In a 2020 survey of a group of palliative care patients, it was noted that only 29% of patients used THC prior to the onset of their illness, and none had used CBD prior to their diagnosis. This suggests that patients are seeking out cannabinoid medicine because of its perceived benefits on chronic disease.

Despite the significant increase in the use of medical cannabis in the elderly, current evidence on the efficacy and safety of medical cannabis and how it helps older adults is still scarce. Further research will allow us to understand the physiological effects of cannabinoids in geriatric and palliative care patient populations in order to better target their clinical applications.

Red de Médicos
ICAN invites you to meet our Network of Doctors trained in the use of medical cannabis in Mexico. We have doctors who can prescribe safe and legal CBD medicine, and you can also find veterinarians who can help our four-legged friends.

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