Medical marijuana, or cannabis, is one of the most popular topics among the Parkinson’s disease (PD) community ― for people with PD, health professionals and researchers, alike. Earlier this year, the Parkinson’s Foundation hosted its first-ever convening on marijuana and Parkinson’s. Among the 46 attendees, of which 17 gave presentations, there was a reoccurring theme: what are the biggest hurdles the PD community faces when it comes to medical marijuana?
This is the first article in a two-part series.
Treating Parkinson’s Symptoms with Cannabis
There is not enough evidence yet to support that medical marijuana can help manage Parkinson’s symptoms, however there are studies on the topic. Unfortunately, they have mixed results. Generally, the studies have been small and some with no control groups. The effects of medical marijuana are not completely understood, especially in the PD population.
The bottom line is that more studies are needed, specifically larger and more rigorously conducted studies.
Based on some observational studies, cannabinoids (the active molecules in marijuana) may potentially benefit some non-motor symptoms of PD including pain, anxiety, sleep problems (insomnia, RBD, RLS), weight loss and nausea. Potential adverse effects include dizziness, blurring of vision, loss of balance, mood and behavioral changes, hallucinations, and impaired cognition and motivation. Better studies are necessary to confirm these benefit and adverse effects for people with PD.
Controlled clinical trials of cannabinoids (where some people receive the drug and some do not) have reported mixed results for treating motor symptomsand levodopa-induced dyskinesia as well as improving quality of life.
While stories and videos exist showing that marijuana can treat PD symptoms, the challenge is showing that cannabis is better and safer than treatments that are currently available. A recent survey shows that the health community does not have a consensus on using cannabis as a treatment. This reflects lack of data, knowledge and training on the subject.
Future studies about medical marijuana and Parkinson’s should follow the highest standards of clinical trials to focus on:
- Delivery type: do specific strains, soft gels, tinctures (alcohol-based cannabis extract), e-liquid (vapor), topicals, infused food, flower products, inhalers and patches treat symptoms differently and have different side effect profiles?
- Dosage: what is the minimum dosage to guarantee effectiveness, what is the maximum dose tolerated and what dose will have a sustained benefit? Furthermore, how does this differ by strain and formulation?
- Effect on motor vs non-motor symptoms: which symptoms can improve, worsen or stay the same with cannabis use?
- Interaction with PD medications: how does cannabis interact with medications taken for PD symptoms?
- Key component: What components of cannabis/marijuana provide the best response in PD with the least risk of side effects? What is the optimal CBD (Cannabidiol) to THC ratio?
- PD-specific side effects: are people with PD uniquely susceptible to certain side effects that are not seen in the general population?
- Population: studies that involve participants in difference stages of the disease.
Lastly, there needs to be a widespread physician education on using cannabis as a treatment ― almost all physicians surveyed agreed that medical school curriculums should include education on cannabis.
→ Danny Bega, MD, MSCI, from Northwestern University Feinberg School of Medicine; Joseph Jankovic, MD, from Baylor College of Medicine; and Karl Kieburtz, MD, MPH, from the University of Rochester, spoke about this topic at the marijuana convening.
Potential Drug Interactions
One surprising fact shared at the meeting is that cannabis-based products have the potential to interact with other medications. Given that people with Parkinson’s may be on multiple medications for other conditions, it is important to be aware of these interactions to avoid complications.
Epidiolex® is the first FDA-approved cannabinoid prescription drug. It is an oral solution of cannabidiol most commonly used to treat rare forms of epilepsy. It has been shown to have interactions with many anti-seizure medications, some antibiotics and medications for lowering cholesterol, pain, anxiety, depression and blood pressure. In some cases, Epidiolex can make these medications more or less potent. In other cases, these medications can make Epidiolex more or less potent. Because Epidiolex largely contains cannabidiol, there is the possibility that other cannabis-based products may also interact with medications in a similar way.
Delta-9-tetrahydrocannibinol (THC) is the primary psychoactive component of marijuana (the part that gives a “high”). It can take a long time to take effect and cannot be easily measured for a therapeutic or medicinal dose. THC can also interact with certain medications such as valproic acid (for bipolar disorder, seizures, and migraines) and can result in increased psychoactive effects of marijuana.
Medical marijuana can be taken in an edible form. Care should be taken with this form, as it takes longer to feel an effect and lasts longer (4-8 hours as opposed to 2-3 hours for smoking or vaporizing). Often, because the effects are slow, people increase their dose, eating more, which can be dangerous. Edibles may also have more toxicity than smoked marijuana, because they are broken down by the liver into more toxic chemicals.
→ Jacqueline Bainbridge, PharmD, FCCP, MSCS, from the University of Colorado, spoke about this topic at the marijuana convening.
The medical marijuana convening brought together a diverse group of experts from academia, clinics, industry, government and the Parkinson's community to establish a consensus on medical marijuana use in PD. The Parkinson’s Foundation will publish its findings on the convening in fall 2019.
Ask the Experts: The Challenges of Using Marijuana as a Parkinson’s Treatment, Part 2
Medical marijuana, or cannabis, is one of the most popular topics among the Parkinson’s disease (PD) community ― for people with PD, health professionals and researchers, alike. Earlier this year, the Parkinson’s Foundation hosted its first-ever convening on marijuana and Parkinson’s. Among the 46 attendees, of which 17 gave presentations, there was a reoccurring theme: what are the biggest hurdles the PD community faces when it comes to medical marijuana?
Adverse Effects
Some of the most common side effects of cannabis-based products include:
- drowsiness and fatigue
- dizziness
- dry mouth
- anxiety
- nausea
- cognitive effects
Specifically, for smoked forms, side effects include cough, increased phlegm and bronchitis. Some rare but important side effects to note include: orthostatic hypotension, paranoia, depression, worsening of coordination of movement and rapid beating of the heart.
Specifically, regarding cognitive function, one review article of several studies found that attention and concentration were impaired in the short term (0-6 hours after use) but largely returned to normal in the longer term (three weeks or longer after use). However, decision making and risk taking were impaired three weeks or more after last cannabis use. Working memory was impaired shortly after use, but did not see any residual or long-term effects. Mixed results were seen as to whether there are long-term effects on impulsivity and verbal fluency after cannabis use.
→ Danny Bega, MD, MSCI, from Northwestern University Feinberg School of Medicine, spoke about this topic at the marijuana convening.
Finding the Right Formula
Physicians and pharmacologists are constantly trying to define the limits of their practice when it comes to cannabis. Not only must researchers find the right formula, they must also find the right delivery method. Cannabis can be delivered in various forms, from liquids to e-liquid (vapor) and inhalers to patches.
One additional challenge is that cannabis products are not highly regulated, so there can be a lot of variation from product to product and even from batch to batch within a single product. This needs to be regulated more so that people can know what is in the product they are purchasing and trust that it is safe.
→ Bill Arnold, CEO of Cannoid, LLC, spoke about this topic at the marijuana convening.
The Effects of Cannabis and Pain on Men VS Women
Of the 20 common conditions that qualify for medical marijuana, chronic pain has substantial evidence supporting the use of cannabis. People with PD report pain as one of the most common non-motor symptoms, which is not always responsive to pain medications.
PD-related pain is most common among women. Differences between men and women specifically in their susceptibility to intoxication and abuse liability have not been studied. Preclinical evidence suggests that female laboratory animals are more sensitive to cannabinoid (THC) relative to males in terms of treating pain, but they are also more sensitive to the abuse-related effects of these drugs. However, female animals develop tolerance to the pain-relieving effects of THC at a faster rate than males, rendering THC close to ineffective in females.
Ziva D. Cooper, PhD, and her colleagues tested cannabis to see if these findings in animals would translate to humans. Her study found that women who heavily smoke cannabis did not show a pain-relieving response, whereas men did. Regardless of pain response, women reported feeling as intoxicated as men and reported liking the cannabis as much as men.
Future studies investigating the use of cannabis and cannabinoids for PD-related pain are warranted. These studies should consider differences between men and women, cannabis experience and adverse effects.
→ Ziva D. Cooper, PhD, from the UCLA Cannabis Research Initiative, spoke about this topic at the marijuana convening.
The medical marijuana convening brought together a diverse group of experts from academia, clinics, industry, government and the Parkinson's community to establish a consensus on medical marijuana use in PD. The Parkinson’s Foundation will publish its findings on the convening in fall 2019.
https://www.parkinson.org/blog/research-roundup/Challenges-of-Marijuana-as-PD-Treatment-Part-2
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