American College of Physicians Internal Medicine Meeting

American College of Physicians Internal Medicine Meeting

April 15, 2019
4 min read

Things physicians need to know about medical marijuana

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Ellie Grossman
Ellie Grossman

PHILADELPHIA — More than 150 years after the first medicinal use of marijuana was recorded, and there is still not an abundance of research surrounding its use for that purpose, according to a speaker at the American College of Physicians Internal Medicine Meeting.

“There is a lot of hype, community discussions, and government actions surrounding marijuana, but the reality is marijuana is akin to a new drug that somehow got approved by the FDA with little research,” Ellie Grossman, MD, MPH, instructor at Harvard Medical School and primary care lead for behavioral health integration at the Cambridge Health Alliance, told Healio Primary Care Today.

The dearth of data has not quelled potential patient interest.

A 2018 Quinnipiac University poll found 93.5% of U.S. voters support marijuana’s use for medical reasons, and 33 states have laws that allow marijuana use for medicinal purposes, according to Grossman.

She and others provided details on what is known about marijuana to assist physicians in answering their own, or their patient’s queries.

Common medical uses

Grossman said limited studies that “showed effectiveness in specific patient populations” led the FDA to approve several cannabis-related products: the oral solution cannabidiol for patients aged 2 years and older with Dravet Syndrome or Lennox-Gastaut Syndrome; dronabinol, a synthetic tetrahydrocannabinol (THC) for nausea/vomiting and AIDS cachexia; and nabilone, another synthetic THC for nausea/vomiting.

She added that in 2017, the National Academy of Medicine reported there was some evidence to suggest using marijuana for chronic pain, chemotherapy-associated nausea and vomiting, and multiple sclerosis-associated spasticity. Grossman noted that the substances used in those studies may not match what is being sold in medical marijuana dispensaries, but there is “some evidence” suggesting a likely benefit for these indications.

Medical Marijuana 
More than 150 years after the first medicinal use of marijuana was recorded, and there is still not an abundance of research surrounding its use for that purpose, according to a speaker at the American College of Physicians Internal Medicine Meeting.


Grossman added that some states also allow medical marijuana use for Huntingdon’s and inflammatory bowel diseases, but there is no evidence of marijuana’s efficacy towards opioid use disorder.

“The fact that there is some evidence suggesting lower opioid doses and fewer opioid prescriptions in states with medical marijuana laws could suggest that medical marijuana has an opioid-sparing effect, thereby preventing patients from using opioids and/or high-dose opioids, and hopefully preventing overdoses and/or development of opioid use disorder,” she said.

Dosing, adverse events

Since there are no medically-approved guidelines to steer dosing recommendations or ingestion method regarding medical marijuana, Grossman explained in an interview the approach she would take with patients.

“Start patients with a small amount of a legally-approved product and advise them to report back to you on how it makes them feel,” she said. “You and the patient need to watch for several big things: difficulty with concentrating or thinking, mood changes, and breathing changes (if using an inhaled product).”

She discussed the limited data that support these assertions during the interview.

“There is evidence to suggest that those aged 25 years and younger who smoke marijuana seem to have some changes in their functional connectivity. But we don’t know if this rewiring is permanent or temporary, or if it is bad or good,” Grossman said.

“This doesn’t mean when a patient is 25 years and 1 day old they can smoke all the marijuana they want, but we do know brain development goes onto the mid-20s, so that is why this age cut-off was considered,” she added.

“Lung and breathing problems are another area of concern. Some studies suggest marijuana use does not impact pulmonary function, but problems with the lung system can take years to develop and studies exploring such consequences of marijuana use were limited in their length,” Grossman continued.

The last “big thing” to watch for is mood and mental health, she said.

“There does seem to be a relationship between psychosis and marijuana use in families that have a history of psychosis. But we don’t have a lot of data to help us ascertain who will experience these symptoms more severely vs. those whose symptoms will be milder,” Grossman said.

“Given its potential for problematic mood side effects, marijuana can also be contraindicated in patients who have bipolar disorder, major depressive disorder, or anxiety disorders,” she added. Other commonly reported adverse events tied to marijuana use include agitation, asthenia, balance problems, disorientation, gastrointestinal effects, euphoria, somnolence, dry mouth, fatigue, hallucinations, and paranoia, Grossman said. There is also an increased risk for cough, wheeze, sputum/phlegm, and lower neonatal birth weight.

Variability, transparency

Grossman noted it is important to be honest with patients regarding the paucity of reliable research surrounding the pros and cons of medical marijuana use.

“While it is true that there is not a lot of great evidence for it being effective, it does not mean that marijuana will not treat the conditions it has been linked to. It just means we do not know yet. We owe it to our patients to help them understand that everything they see on the internet or hear from their friends might be true and it also might not be true,” Grossman said.

“Do not be a fearmonger, but be wary of recommending medical marijuana and use caution when doing so,” she added. – by Janel Miller

References: Grossman E. “Medical marijuana: Use and management update.” Presented at: American College of Physicians Internal Medicine Meeting; April 11-13, 2019; Philadelphia.

Quinnipiac University. Poll release details. Accessed April 4, 2019.

Disclosures: Grossman does not report any relevant financial disclosures.