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Cannabis could help manage symptoms of some neurological conditions
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Cannabis could help manage symptoms of some neurological conditions

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Cannabis Update

Loren Bonner

Humand profile formed of cannabis leaves.

The data on cannabis and its components for treatment of neurological disorders are plentiful, according to Michele Faulkner, PharmD, FASHP. “Cannabis and neurological disorders is a huge topic,” said Faulkner during an APhA2021 Virtual session on cannabis products to treat neurological disorders.

Most pharmacists are probably familiar with cannabis as a treatment for epilepsy. In 2018, FDA approved Epidiolex (Greenwich Biosciences) as the first-ever product containing cannabidiol. The drug is indicated for two rare and severe forms of epilepsy in patients ages 2 years and older. “The overwhelming majority of data concerning cannabis as a potential therapy in neurology has been derived from surveys of users [and] from open-label studies, and there is quite a high potential for bias in a lot of this information,” said Faulkner.

Faulkner, a professor of pharmacy practice and neurology at Creighton University Schools of Pharmacy and Medicine in Nebraska, said there is no evidence that cannabis can cure any neurological disease or that it slows down any progressive diseases, such as Parkinson’s.

What is cannabis?

The cannabis plant contains 554 compounds. These compounds, or active chemicals, include 113 cannabinoids, two of which are tetrahydrocannabinol (THC) and cannabidiol (CBD).

“As we look at pharmacological actions and expected therapeutic responses, a name label is not going to help us, but instead knowing whether it’s a THC type, or CBD type, or hybrid type,” said Kari Franson, PharmD, PhD, BCPP, professor and associate dean at the University of Southern California.

Although it’s still an area of evolving research, cannabinoids such as THC and CBD are known to have different effects on the body. THC binds to cannabinoid receptors in the body, while CBD may interact indirectly with cannabinoid receptors. THC is the chemical responsible for the psychoactive quality of cannabis, but it also has antinausea and analgesic effects. CBD, which has no psychoactive properties, is said to help with inflammation. Other compounds in the plant, such as the terpenes and flavonoids, may play a synergistic role in the therapeutic effects of cannabis—what’s known as the “entourage effect.”

Fiona Oxsher, PhD, cofounder and general manager of LKN Extractions, said that learning about the body’s endocannabinoid system—which was only discovered in 2002—helps us understand how cannabinoids work.

The endocannabinoid system controls a person’s response to stress, as well as one’s mood, appetite, energy balance, and more. In an April 21, 2021, APhA webinar, Oxsher explained that our bodies have been increasingly void of cannabinoids because of our environment, the food we eat, and other factors. Plants with cannabinoids are a way to saturate this system—the CB1 and CB2 receptors, specifically—she said.

Cannabinoids are also present in rosemary, echinacea, kava, and other plants. “But cannabis has the highest percentage of cannabinoids,” said Oxsher.

Inconclusive data

For most neurological diseases, cannabis can help with symptom
management. During her presentation, Faulkner discussed the research on a few neurological conditions outside of epilepsy: multiple sclerosis, Parkinson’s disease, and headache disorders.

“We need to be honest with our patients that the efficacy data is inconclusive,” said Faulkner. “Changes in legal status have outpaced scientific development in the area of cannabis research, and it’s really unprecedented that we have indications without any strong clinical data that are being included as acceptable indications for the receipt of medical cannabis.”

For example, Parkinson’s disease is included in the accepted indications for medical cannabis in 17 states, despite statements from organizations like the American Academy of Neurology that say cannabis does not work for motor symptoms or levodopa-induced dyskinesia in patients with Parkinson’s disease. 

Drug interactions

Most pharmacists are probably familiar with patients inquiring about CBD products.

“Patients are already using [CBD] or will come to pharmacists saying they want to explore it,” said Michael Deme, PharmD, a clinical pharmacist at RxClinic Pharmacy in Charlotte, NC, during the April 21 APhA webinar.

Even though data are lacking on CBD and specific drug interactions, Deme said it’s an area where a pharmacist’s expertise is needed.

“We do know that CBD is metabolized by the liver with enzymes CYP2C19 and CYP3A4,” said Deme. “Most pharmacists know those are major players in all other drug metabolism.”

To cite just one example, if a patient is using a CBD product and is on carbamazepine, which is a CYP2C19 inducer, the CDB dose might not be as effective for them. “Maybe the patient is not getting any benefits from CBD after being on it for a while. Maybe their dose is too low because they are on an inducer medication.” The opposite can also hold true when a patient is on a CYP2C19 inhibitor, in which CBD might not be metabolized as well and could be causing an adverse effect.

According to Faulkner, there are some known drug interactions with cannabidiol. “In particular, it interacts with several of the other antiepileptic medications that we use for the treatment of these same disorders,” she said.

Faulkner said medication doses for diazepam, clobazam, and stiripentol, for example, will likely need to be reduced to prevent toxicity in patients.  

She said it’s also worth noting that elevations in liver enzymes seem to occur more readily with coadministration of valproic acids. “This is important to know if you have a family member who is seeking out cannabis for use in a child with seizures who is on some of these conventional therapies without the oversight of a medical practitioner,” Faulkner said.

Full- vs. broad-spectrum cannabis products

Full spectrum has the full complement of major and minor cannabinoids—these products have both CBD and THC as well as terpenes and phytochemicals. On the other hand, broad-spectrum products are a THC alternative to full-spectrum products; they have everything in them but THC.

Hemp and marijuana fall under different federal designations. Hemp is a variety of cannabis grown specifically for fiber that is used for industrial purposes. The 2018 Farm Bill legalized the production and sale of hemp and its extracts. Hemp has less than 0.3% of THC. Marijuana has greater than 0.3% of THC. Marijuana is considered a Schedule I drug by DEA and is federally illegal.



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