Managing Chronic Pain in the Elderly

Aging influences the biochemical and physiological effects of drugs on the body. For example, a slow metabolism, a normal part of aging, can increase the likelihood of experiencing side effects such as nausea, vomiting, constipation, and falls in seniors who take prescription medicines such as opioids for pain management, according to the National Safety Report.

Americans over the age of 65 make up 13 percent of the total population, but they account for the use of 34 percent all prescription drugs, and 30 percent of all over-the-counter (OTC) drugs, according to the National Council on Patient Information Education (NCPIE). The use of medical marijuana is also rising in the aging population for treating conditions such as cancer, Parkinson's disease, post-traumatic stress disorder, ulcerative colitis, Crohn's disease, and multiple sclerosis, according to a systematic review in Clinical Psychopharmacology and Neuroscience. Yet, current evidence on the efficacy and safety of the drug in the elderly is limited.

Studying Cannabis for Pain

To test the safety and efficacy of medical cannabis for treating pain in older adults, researchers in Israel identified 1,186 patients over the age of 65 who initiated treatment with medical cannabis from Israel's largest medical cannabis supplier, from January 2015 to October 2017. More than 60 percent of patients had been prescribed cannabis to treat pain, including pain related to cancer.

Patients received treatment either as an oil or by smoking or using vaporization. Before starting treatment, a nurse took each patient's medical history, including the reason for needing cannabis, medication-use habits, a detailed list of symptoms, a quality of life assessment, and demographic data. The nurse then recommended specific cannabis strains for each patient's condition.

Measuring Efficacy

Researchers followed up with patients after one month and again six months after treatment via telephone interview. At the six-month follow-up, the researchers assessed the occurrence and frequency of all side effects, including headache, dizziness, and nausea. They also assessed cannabis efficacy by measuring quality of life, pain intensity on a 0 to 10-point scale (0=no pain, 10=worst pain imaginable), patients' perception of the drug's effect on their condition, and treatment success.

Medical Cannabis Improved Pain

After six months, medical cannabis significantly improved pain and quality of life for older adults with minimal side effects. More than 93 percent of 901 participants reported their pain dropped from eight to four on the 10-point scale. Quality of life upgraded from "bad" or "very bad" to "good" or "very good" in approximately 60 percent of patients. More than 70 percent of patients reported experiencing moderate to significant improvement in their condition.

Dizziness (9.7 percent) and dry mouth (7.1 percent) were among the most common side effects. After six months, a total of 18.1 percent of patients stopped using opioid analgesics or reduced their dose.

The researchers say their findings suggest that medical cannabis is safe and effective with minimal to no side effects for patients age 65 and older. Cannabis may also decrease this aging population's dependence on prescription medications, including opioids.

Study Limitations

Researchers acknowledge that the observational nature of the study only allows them to determine a link between cannabinoids and pain relief not causality. In addition, most of the patients were using a mixture of cannabis strain, which meant researchers couldn't determine the exact dose of active drug each patient was getting.

They say additional study is needed, including double-blind, randomized-controlled trials.

An Expert Comments

The study is encouraging, says Brain J. Wainger, MD, PhD, assistant professor of neurology and anesthesiology at Harvard Medical School and an attending physician at Massachusetts General Hospital. But because it was observational, he's cautious about the results. With studies on pain, he says, researchers have to take into account the placebo effect—a response related to a person's expectation of benefit—when interpreting the results. "It's hard to interpret the magnitude of the benefit that's due to the cannabinoids, although I think it's encouraging, and warrants additional studies." Until then, he says the evidence supporting opioids for pain management is stronger than for cannabinoids.

Dr. Wainger says opioids are a second choice for treating pain, after over-the-counter painkillers such as nonsteroidal anti-inflammatory drugs and acetaminophen, because of concerns about safety and addiction. Cannabinoids would be considered a third choice, he says, because the data about efficacy are weaker.

For more about medical cannabis and chronic conditions, read Weedbackers.