March 27, 2019

Advice from UW pharmacists on senior use of marijuana

marijuana foliage

Marijuana use among older adults has soared in recent years despite little being known about the effectiveness and safety of the drug in people 65 and older. That’s resulted in more seniors asking health care providers about marijuana use: Is it safe? How much to use? Where to buy?

Now, a group of University of Washington professors has gone on the record to recommend ways to answer some of these questions and reduce the potential harm from marijuana use in this vulnerable population.

Zach Marcum

Zach Marcum, Assistant Director of Research for the Plein Center for Geriatric Pharmacy

“Start low, go slow,” said Zach Marcum, assistant director of research for the Plein Center for Geriatric Pharmacy at the UW School of Pharmacy. He’s the lead author of a letter to the editor about marijuana use in older adults recently published in the Annals of Pharmacotherapy. “We discourage marijuana use, especially in the elderly. But we also acknowledge the reality that people, including seniors, are trying marijuana. If they’re going to use, use safely.”

Researchers realize that older adults are using weed, even to just try it out. If seniors are going to try marijuana, they should keep some basic safety guidelines in mind:

  • Buy from a reputable source and avoid buying marijuana products over the internet or on the street. Remember that even the most reputable-seeming retailers are selling an unregulated product that may or may not contain the exact amounts of the chemical compounds on the label.
  • Choose a product with a high CBD to THC ratio to limit the psychoactive effect. The experts recommend topical or transdermal preparation over anything that’s inhaled or eaten.
  • Start low and go slow. Use one-quarter to one-half of the recommended dose and monitor for potential adverse effects.

There are good reasons for older adults to worry about potential unforeseen consequences of using marijuana. Despite heavy marketing from the marijuana industry to older adults, this same group often is excluded from clinical research and trials. Changes to the body as one ages includes kidney and liver function that may alter the way the body reacts to the chemicals in weed. And little is known about how marijuana works with other medicines people might be taking.

While there’s much interest in marijuana use for a number of ailments, much more research is needed, Marcum said.

“There is still a need for quality studies regarding potential risks and benefits,” he writes in the journal.

Health care providers should ask their patients about marijuana use and employ risk reduction strategies, helping patients to make informed decisions. Pharmacists, Marcum notes, are uniquely positioned to engage older adults in these conversations as part of an overall medication management process.

Co-authors on the letter to the editor include Sarah Tu, and Dr. Lianne Hirano and Carol Crawford of UW Medicine.

Jackson Holtz


Learn more about cannabis use in older adults at out upcoming public lecture.
In Case You Missed It! Medications Update for 2019
Medication Headlines & Your Health
May 34, 2019 | 5:00 PM | Foege Auditorium, UW Seattle Campus
More information and registration online