PHILADELPHIA — Medical cannabis may be safe and effective in the treatment of a wide range of chronic symptoms related to various neurologic illnesses in elderly patients, early research suggests.

In a preliminary study, investigators at the Dent Neurologic Institute in Buffalo, New York, found that the drug provided elderly patients relief from chronic pain, sleep disorders, and anxiety related to diseases such as amyotrophic lateral sclerosis, Parkinson disease, neuropathy, spinal cord damage, and multiple sclerosis.

"Our findings show that medical marijuana is well-tolerated in people age 75 and older and may improve symptoms like chronic pain and anxiety," study investigator Laszlo Mechtler, MD, said in a release.

"With legalization in many states, medical marijuana has become a popular treatment option among people with chronic diseases and disorders, yet there is limited research, especially in older people," he added.

The findings were presented here at the American Academy of Neurology (AAN) 2019 Annual Meeting.

Promising Findings

Estimates from the Centers for Disease Control and Prevention show that approximately 80% of older adults in the United States have at least one chronic condition. In addition, it is estimated that 2.1 million Americans use medical cannabis.

To evaluate the efficacy and adverse events of medical cannabis in an elderly population, the investigators conducted a retrospective chart review of patients aged 75 years or older who were attending a neurologic outpatient clinic.

The study included 204 patients (129 women and 75 men) enrolled in New York State's Medical Marijuana Program. The average age of the participants was 81. The patients took tetrahydrocannabinol (THC) and cannabidiol (CBD), the main active ingredients in cannabis, in various ratios for an average of 4 months and had regular follow-up visits.

Medical cannabis was taken by mouth as a liquid extract tincture, capsule, or via an electronic vaporizer.

Results of the retrospective study showed that 69% of participants experienced some symptom relief. The most common conditions that improved were pain, for which 49% of patients experienced relief; sleep symptoms, for which 18% experienced relief; neuropathy, for which 15% experienced improvement; and anxiety, for which 10% experienced relief.

Initially, 34% of the cohort experienced side effects. However, after adjusting the dose, only 21% reported side effects. The most common side effects were sleepiness (13%), balance problems (7%), and gastrointestinal disturbances (7%). Three percent discontinued use because of adverse events.

Interestingly, the results showed a decrease in opioid use in 32% of participants.

"Our findings are promising and can help fuel further research into medical marijuana as an additional option for this group of people who often have chronic conditions," the investigators note.

Limitations of the study were its retrospective design and its reliance on self-report with respect to symptom relief. Additional randomized, placebo-controlled studies are needed, said Mechtler.

"Future research should focus on symptoms like sleepiness and balance problems, as well as efficacy and optimal dosing," he said.

Rapid Uptick in the Elderly

Commenting on the findings for Medscape Medical News, Mark Wallace, MD, professor of clinical anesthesiology and chief of the Division of Pain Medicine, University of California, San Diego, who has extensive experience researching and treating pain patients with medical cannabis, said the study is unique in that it involved a geriatric population.

He noted that in his clinical practice, geriatric patients are the fastest growing group of medical cannabis users.

This rapid uptick of use among the elderly is not surprising, he said.

"These patients are looking for alternatives. The medications we currently have on the market [for the treatment of neuropathic pain] probably reduce pain by no more than 30% in no more than 50% of the patients — that's pretty low."

In addition, he said, there is very limited evidence to support the long-term use of opioids, and in view of the current opioid crisis, many patients want to get off these medications.

Because cannabis is a Schedule 1 substance, no head-to-head studies have compared it to other currently available agents for chronic pain, so "these types of retrospective studies are actually very important," Wallace said.

The study's finding that cannabis may help reduce chronic opioid use, he added, mirrors the clinical experience at his center.

Reduced Opioid Use

"These patients come to me on high-dose opioids, and we are able to get them off opioids [by using medical cannabis]," he said.

"Patients who are taking high-dose opioids are constantly looking at the clock, waiting for the time when they can take their next dose, and are constantly monitoring their supply. When supply goes down, anxiety goes up. It completely controls their life. But when you put them on medical cannabis, that behavior completely goes away and they feel they have their lives back," Wallace added.

Determining the ratio of CBD to THC is a challenge and requires an individualized approach. However, said Wallace, for daytime use, it appears that a CBD-to-THC ratio of 20:1 may be best. At night, a 1:1 ratio appears most effective.

"Even in patients where [medical cannabis] doesn't help their pain, many — I would say upwards of 80% — opt to stay on it because it helps their sleep," he said.

It is important to note that medical cannabis is administered in very small doses — typically starting at a range of about 1 mg to 2 mg — and is very different from the cannabis that is used recreationally.

"The doses that are being marketed on the recreational side have no place on the medical side. It is way too much and can actually worsen the patient's pain, worsen sleep, and can cause agitation and paranoia," he said.

There is a misperception that treating elderly patients with medical cannabis may be unsafe and increase the risk for falls due to dizziness or cognitive impairment. However, Wallace said, the clinical experience at his center suggests this is not the case.

"We are finding that the geriatric population can successfully use medical cannabis without any adverse effects. I am having a lot of success with geriatric patients. It is amazing that even patients in their 90s are using it successfully," he said.

The study was supported by the Dent Family Foundation. Mechtler and Wallace report no relevant financial relationships.

American Academy of Neurology (AAN) 2019 Annual Meeting: Abstract P4.1-014. Presented May 8, 2019.

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