#338 LIVE! Medical Cannabis: Is it still dope?

May 30, 2022 | By Matthew Watto, MD

Video

It’s high time we revisit the benefits and harms

Master the ins-and-outs of medical cannabis! Dr. Julia Arnsten (@DrArnsten) will lead us through the initial evaluation of a patient interested in medical cannabis, summarize the state of evidence for the benefits and harms, lay out a schema for dosing and formulations, provide pearls on how to counsel patients, and more!

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Credits

• Producer and Writer: Matthew Watto MD, FACP
• Show Notes, Infographic, and Cover Art: Malini Gandhi
• Hosts: Matthew Watto MD, FACP; Paul Williams MD, FACP   
• Associate Editor: Leah Witt MD
• Showrunner: Matthew Watto MD, FACP
• Production Team: PodPaste
• Guest: Julia Arnsten MD, MPH

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Show Segments

• Intro, disclaimer, guest bio
• Guest one-liner, Picks of the Week
• Definitions and terminology
• A brief history of medical cannabis
• Case from Kashlak
• History to obtain for a patient interested in medical cannabis
• Medical cannabis dosing and formulations
• Conditions for which the evidence supports considering medical cannabis
• Risks of medical cannabis
• Disparities in access to medical cannabis
• Does medical cannabis reduce opioid use?
• Outro

Medical Cannabis Pearls

1. When evaluating a patient interested in certification for medical cannabis, it is important to take a comprehensive history and have a non-judgmental conversation about their experience with cannabis.
2. Per the 2017 National Academies of Science, Engineering, and Medicine guidelines, the three conditions for which the evidence is sufficient to consider recommending medical cannabis are: nausea / vomiting associated with chemotherapy, spasticity associated with multiple sclerosis, and chronic pain. The most common condition for which patients are seeking medical cannabis is chronic pain.
3. CBD has few known side effects. THC has several important adverse effects including: intoxication, cardiac effects (should be used with caution in people with coronary artery disease), and psychiatric / neurocognitive effects (should be used with caution in people with psychiatric comorbidities or patients who are young with brains that are still developing.)
4. Regarding the formulation of medical cannabis, patients should be encouraged to use tinctures or edibles rather than smoking, as smoking cannabis has been associated with respiratory symptoms / chronic bronchitis (as well as tobacco exposure if the cannabis is rolled in joints with tobacco or wrapped in tobacco paper.)
5. For patients currently using cannabis, Dr. Arnsten recommends a therapeutic dose of medical cannabis equal to 50% or less of what they are currently using (so for someone using 1 oz of cannabis per month, this would be 40-50 mg of THC, taken in 10-20 mg doses every 4-8 hours).
6. Significant disparities exist in access to medical cannabis due to the cumbersome certification process and expense associated with purchasing the product.

Medical Cannabis – Notes

Background on Medical Cannabis

Cannabis is currently approved for medical use in 37 states (NCSL, 2022) Dr. Arnsten describes medical cannabis as a “pharmaceutical that can help people with specific symptoms using specific doses of the active ingredients in the cannabis plant.”

Terminology

Terminology: “Marijuana” vs “cannabis”: The term “cannabis” refers to the cannabis plant, which contains various chemical substances, including THC, CBD, and other cannabinoids and terpenes (National Academies of Sciences, Engineering, and Medicine, 2017).  The term “marijuana” is a  “cultural rather than scientific term” with a particular history in the United States, linked to racism and xenophobia, according to Dr. Arnsten. Dr. Arnsten notes that the appropriate term to use is “cannabis” rather than “marijuana.”

Terminology: “Recreational use” vs “non-medical use“ or “adult use” – Dr. Arnsten prefers the terms “non-medical use” or “adult use” rather than “recreational use.” She stresses that over half of individuals who are purchasing cannabis in a dispensary without a medical card are buying it to treat a particular symptom like pain or insomnia.

Brief notes on the history of medical cannabis in the United States

In the United States, early use of cannabis in the medical setting was in the form of tinctures, which were widely prescribed by doctors during the 19th and early 20th centuries for a range of symptoms, including cough, pain, menstrual cramps, and neuralgia. Then, during Prohibition and the Great Depression, alcohol and cannabis were prohibited, and the government began an effort to “free society” from cannabis, according to Dr. Arnsten. The government attempted to link cannabis to immigrants from Mexico, and in this context the term “marijuana” was coined to associate cannabis with Mexican immigrants. Later in the twentieth century, the era of Nixon and the War on Drugs had a profound effect on the history of medical cannabis, ultimately resulting in wildly disproportionate rates of incarceration for cannabis offenses for people of color.

Prescribing Medical Cannabis

History to obtain for a patient interested in medical cannabis

When taking the history of a patient interested in certification for medical cannabis, Dr. Arnsten notes that the following items are critical:

• Comprehensive pain assessment: According to Dr. Arnsten, for patients interested in medical cannabis for chronic pain relief, it is important to take a thorough pain history, including the type of pain, when it started, work-up to date, other medication regimens tried (NSAIDs, acetaminophen, muscle relaxants, etc.) and response to treatment, whether physical therapy has been pursued and whether it helped, etc. Records from other specialists, including pain management, rheumatology, neurology, orthopedics, and others, can be helpful. 
• Non-judgmental conversation about a patient’s experience with cannabis: For patients already using cannabis, providers should engage in a non-judgmental conversation about their experience with cannabis, including how they use cannabis, how often, in what form, and how it helps them (Ross et al, 2022). According to Dr. Arnsten, it is important to try to tease out when the patient is using cannabis to relieve pain or get sleep versus other reasons such as social situations or boredom, and to not be judgmental about the latter reasons. 

Conditions for which the evidence supports considering medical cannabis

There are now tens of thousands articles on PubMed exploring the conditions in which medical cannabis may be useful. Five years ago, a panel from the National Academy of Science, Engineering, and Medicine convened to review this literature and develop a set of guidelines on medical cannabis use (National Academies of Sciences, Engineering, and Medicine, 2017.) The guideline panel identified three conditions for which the evidence is sufficient to consider recommending medical cannabis:

1. Nausea / vomiting associated with chemotherapy
2. Spasticity associated with multiple sclerosis
3. Chronic pain (Whiting et al, 2015) – According to Dr. Arnsten, the category of chronic pain is broad, and evidence for the efficacy of cannabis is strongest for neuropathic pain (Nugent et al, 2017; Allan et al, 2018). Dr. Arnsten stresses that for patients not already using cannabis, cannabis would not be something to start as a first-line option for chronic pain; patients should go through a number of other modalities for chronic pain treatment before considering cannabis (Allan et al, 2018). Additionally, Dr. Arnsten emphasizes that setting expectations about the degree of pain relief to expect is important: she usually counsels her patients that about ½ of people tend to obtain some pain relief from medical cannabis, though this benefit is usually modest, with a usual reduction in pain of around 30%. 

There are many other conditions for which patients can be certified for medical cannabis use that do not have as robust an evidence base as these three, and Dr. Arnsten notes that for many disease states the “use of cannabis and enthusiasm is ahead of the evidence.” She points out that the lists of conditions for which patients can be certified to receive medical cannabis are usually generated by politicians, not doctors, and vary from state to state. 

The efficacy of cannabis for anxiety is less clear than for chronic pain (National Academies of Sciences, Engineering, and Medicine, 2017). Dr. Arnsten notes that the situation can be particularly complicated when a patient is using cannabis for both chronic pain and anxiety, as it can be difficult to tease out what they are medicating and how the cannabis is helping them. As the literature on cannabis use for anxiety develops further, Dr. Arnsten said that she suspects that THC will likely worsen anxiety in high doses but may be effective at low doses, while she suspects that CBD will likely be effective for anxiety.

Dr. Arnsten stresses that the major barrier to rigorously analyzing the potential therapeutic benefits of cannabis is the current status of cannabis as a Schedule 1 substance (Ross et al, 2022). This fact means that conducting medical research on cannabis is extraordinarily difficult and demands “lots of perseverance.” Dr. Arnsten notes that cannabis for research must be acquired through the federal government (and there are questions about whether this cannabis is actually the same as cannabis acquired from proprietary companies), and that getting research studies on cannabis off the ground often requires 4-5 years of paperwork. As a result of these barriers to research, answers to important questions about the therapeutic efficacy of cannabis are not available. 

Counseling on risks of medical cannabis

According to Dr. Arnsten, CBD has few side effects of which we are aware. High doses of CBD (for instance, doses used for severe seizure disorders) have been linked to liver enzyme abnormalities (Ewing et al, 2019;  Samanta, 2019). However, doses of CBD used by most patients are generally benign.

THC, on the other hand, has several important adverse effects: 

1. Intoxication – Dr. Arnsten notes that the most important unwanted side effect of THC she counsels about is being high: she stresses that being high is not desired, as it interferes with the ability to ascertain whether or not the cannabis is working to treat the pain.
2. Cardiac effects – THC can acutely induce tachycardia and hypertension, which may pose a risk in patients with coronary artery disease (CAD) (DeFillipis et al, 2020). Therefore, THC should be used with caution in patients with a history of CAD. If CAD is present, a careful history should be obtained to ensure that the CAD is stable (as unstable CAD is a contraindication to THC use); for those with stable CAD, THC should be started at a low dose.
3. Psychiatric and neurocognitive effects: Multiple observational studies have found associations between smoking cannabis and various psychiatric and neurocognitive disorders, including depression and psychosis (Marconi et al, 2016; Moore et al, 2007; Lev-Ran et al, 2014; National Academies of Sciences, Engineering, and Medicine, 2017). While associations do not imply causation, Dr. Arnsten stresses that given the quantity of observational data, it is prudent to be extremely thoughtful about prescribing cannabis in those with psychiatric comorbidities or who are young with brains that are still developing.

Dosing medical cannabis

When determining the appropriate starting dosage of medical cannabis for a patient who is already using cannabis, Dr. Arnsten will start with a thorough history of how often the person buys cannabis and how much they usually purchase (Ross et al, 2022). One ounce (1 oz) of cannabis is equal to 28,000 mg total cannabinoids. Most street cannabis is estimated to be about 10% THC. Thus, if a person is using 1 oz of cannabis per month, this means they are using 28,000 mg total cannabinoids (or 2,800 mg THC per month), which is equivalent to 930 mg total cannabinoids daily (or 93 mg THC daily) (Ross et al, 2022).

For patients currently using cannabis, Dr. Arnsten recommends a therapeutic dose of medical cannabis equal to 50% or less of what they are currently taking (so for someone using 1 oz of cannabis per month, this would be 40-50 mg of THC, taken in 10-20 mg doses every 4-8 hours) (Ross et al, 2022). She will initially start a lower dose for the first 2-3 days of medical cannabis use, and then incrementally increase until the therapeutic dose is reached.

Different formulations of cannabis are available with different proportions of THC:CBD: in New York, the formulations are 1:1 THC:CBD or 20:1 THC:CBD (formulations can vary state-to-state). Dr. Arnsten recommends that the cannabis formulation be tailored to the individual based on their cannabis use at time of assessment: if they have no or minimal cannabis use, a 1:1 THC:CBD formulation of medical cannabis should be used, while if they use cannabis more heavily, a 20:1 THC:CBD formulation of medical cannabis would be preferred initially to help treat their pain (with a plan to transition eventually to a 1:1 formulation) (Ross et al, 2022).  In patients with heavier baseline cannabis use, Dr. Arnsten says that a harm reduction approach should be adopted, with the aim to get patients on a lower dose that helps them but doesn’t put them at risk.

In titrating medical cannabis dosage, Dr. Arnsen encourages patients to keep a diary of how much medical cannabis they take and how they feel each time. Then, over the next 4-6 weeks, she works to find a dose that works best for them.

Cannabis formulations

Dr. Arnsten encourages use of tinctures or edibles (including pills, gel caps, or gummies), and discourages smoking or baked goods. During her conversations with patients, she provides counseling on why smoking cannabis is harmful, explaining how cannabis rolled in joints with tobacco or wrapped in tobacco paper can expose patients to the risks of tobacco. Additionally, even if tobacco is not involved, long-term cannabis smoking can have harmful pulmonary effects, including respiratory symptoms and more frequent chronic bronchitis episodes (Tetrault et al, 2007; National Academies of Sciences, Engineering, and Medicine, 2017).

If patients are smoking cannabis at baseline, Dr. Arnsten will explain to them that the goal is to stop smoking cannabis and move entirely to the medical product. She acknowledges that this may not happen immediately, though she tells her patients that they should abstain from smoking cannabis for at least 24 hours prior to starting the medical product, so that they can understand the effect of the medical product.

For those who are accustomed to smoking cannabis and are transitioning to tinctures or edibles, Dr. Arnsten will explain to them that they should expect a different experience. The effect timing is one notable difference; while patients will usually feel an effect from smoking in about 5 minutes, tinctures and edibles usually take between 60 and 90 minutes to take effect. She recommends that patients take edibles a couple of hours before they go to bed, so they have time to see how it is affecting them.

Disparities in access to medical cannabis

Dr. Arnsten emphasizes that there are notable disparities in access to medical cannabis. To undergo the certification process, an individual needs to have Internet access, access to a healthcare provider, and to pay a fee for the evaluation / certification process (Ross et al, 2022). At Montefiore, Dr. Arnsten has developed an embedded program within primary care so patients don’t need to pay for the evaluation process (Ross et al, 2022). However, they still are required to pay for the product when they get to the dispensary, which many can’t afford (Ross et al, 2022): Dr. Arnsten notes that only about half of the people that her program certifies end up going to the dispensary and purchasing the product. In order to save money, many patients also space out their medical cannabis supply over a longer period of time, and often don’t end up getting up to a therapeutic dose and thus may not experience full therapeutic efficacy. Additionally, Dr. Arnsten notes that this cumbersome system has spawned the growth of many predatory programs such as online and telephone certifiers that take advantage of people. She stresses that pushing for more equity in access to medical cannabis is critical.

Does medical cannabis reduce opioid use?

In the medical community, there is interest in whether medical cannabis can reduce use of opioids. Results from ecological studies investigating whether prescription of opioids is lower in states that have legalized medical cannabis have been conflicting. However, Dr. Arnsten notes that these studies have not addressed the real question, which is: for a given patient, does starting medical cannabis lead to use of less opioids? This question has yet to be answered, and is the subject of an ongoing research study at Montefiore (Cunningham et al, 2020.)

Links

1. David Byrne’s American Utopia
2. The Lehman Trilogy
3. Severance 
4. Zelda BOTW

Goal

Listeners will receive updates on the current state of medical cannabis and recognize potential benefits and harms. 

Learning objectives

After listening to this episode listeners will be able to…

1. Reflect about the benefits and harms of medical cannabis
2. Understand for which conditions medical cannabis may provide benefit
3. Provide patients with individualized medical cannabis treatment guidance

Disclosures

Dr. Arnsten reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures.

Citation

Watto MF, Arnsten J, Gandhi MM, Williams PN. “#335 LIVE! Medical Cannabis: Is it still dope?”. The Curbsiders Internal Medicine Podcast. http://thecurbsiders.com/episode-list. May 30, 2022.