Considerations for unapproved cannabinoids
The authors note several factors to consider if prescribing or recommending a nonapproved, nonregulated cannabis medicine, including the ”differences between registered plant-derived cannabis medicines, synthetic cannabis medicines, and unregistered hemp-derived products.” Epidiolex is plant derived while other cannabis-derived medications (Marinol, Syndos, and Cesamet) that have been, such as nausea associated with chemotherapy, are synthetic.
The guidance document notes several reasons to use a regulated medication instead of an unregulated product:
- Manufacturing processes can differ for unregulated products, including inconsistency in batches and unknown shelf life.
- Quality control processes, including risk of impurities, are much better with regulated products, which also have a system in place for safety recalls.
- More scientific evidence is available for regulated products.
- Safety surveillance reporting is more robust and standardized for regulated products whereas adverse event reporting is less reliable for unregulated products.
- Nonregulated products are rarely covered by insurance or other reimbursement.
Legal considerations will also vary by jurisdiction. ”Right now in the U.S. we have a confused legality where state level programs are still technically illegal at the federal level and I imagine there are some quality differences amongst dispensaries and states,” Dr. Freedman said. “Whenever there is disagreement between state and federal laws, this creates tension for our patients.” He noted, for example, that a patient using a CBD product that contains THC may, even if legal in their state, beat an airport since it is not FDA approved and is not legal, according to the Drug Enforcement Agency.
The authors noted that inadequate data on long-term CBD use and data on neurodevelopmental effects of THC in children, teens, and young adults means THC products should be contraindicated for these age groups. (Epidiolex has less than 2% THC.) Drug interactions should also be considered, particularly for clobazam, CYP3A4 inhibitors or inducers (including St. John’s wort), digoxin, or a mechanistic target of rapamycin inhibitor.
Dr. Freedman said that most neurologists are comfortable prescribing Epidiolex since it has FDA approval while prescribing unapproved products varies more in the field. “Now that many states have compassionate use programs for medical marijuana, some neurologists do this as well,” Dr. Freedman said. Patients often ask about unregulated CBD or CBD+THC products because they’re seen as “natural and therefore better than manufactured pharmaceuticals.”
“I think this is the naturalistic fallacy at work and try to educate my patients on that since our only high-level data to show marijuana products work for epilepsy comes from a pharmaceutical company,” Dr. Freedman said. “My reasons for hesitating on compassionate use are that there is often THC, with variable amounts of concentration, and we know that THC can harm the developing pediatric brain.”
Dosing and adverse effects
Pediatric and adult dosing differences need to be considered, and “patient response (efficacy and toxicity) to these medications varies widely,” the authors noted. They advised getting serum transaminases (ALT and AST) and total bilirubin levels before beginning treatment. All patients should begin Epidiolex at a low dose, such as 2-5 mg/kg per day of CBD in two divided doses, the authors advise, and titrate slowly while monitoring for side effects (no more than 5 mg/kg per day per week). The current dosing range for CBD is 5-20 mg/kg per day in two divided doses, with higher rates involving more risk of adverse events.
“Note that some cannabinoids auto-inhibit their own metabolism and some have active metabolites with longer half-lives,” the authors wrote. “Therefore, dose or frequency may need to be reduced over time, unless tolerance occurs.” These doses, specific to Epidiolex, “cannot necessarily be applied to other oral CBD formulations or other types of epilepsy.” This guidance also does not apply to inhaled or transdermal routes of administration.
The most common adverse events were sleepiness – which occurred in up to 60% of trial participants – as well as diarrhea, decreases in appetite and weight, and drug interactions. Risk of hepatotoxicity means there’s a need to monitor liver function and adjust dosing for patients with moderate or severe hepatic impairment. “Other short-term side effects reported only with THC-containing cannabinoid compounds include increased risk of cardiac and cerebrovascular events, anxiety and psychosis risk, dependency, and withdrawal,” the authors wrote.
Though no withdrawal syndrome has been linked to stopping CBD, the authors suggested decreasing the dose by 10% every 2 days if stopping is not urgent.
“The key points to this issue are that CBD and all marijuana products need to be safe and regulated,” Dr. Freedman said. “Any claims about them need to be backed by high-quality evidence looking at that specific product for that specific condition.”
Dr. Freedman noted the need for children to receive treatment from clinicians with expertise in their specific condition since many other evidence-based treatments exist even for patients with epilepsy syndromes that are difficult to treat, such as other medications, surgery, and specialized diets.
“We need to fix the inconsistent regulation between over-the-counter CBD products, state dispensaries, and federal laws,” Dr. Freedman added. “Any medicine being used to treat children should be held to the same FDA standard of safety and efficacy.”
Dr. Freedman and the authors had no conflicts of interest. No external funding was noted.