Marijuana regulation is complex and there are many areas of regulatory concern that physical therapy boards need to keep in mind. This article is based on a presentation by Troy Costales and Suzanne Tinsley at the 2019 FSBPT Annual Meeting.
It doesn’t matter if it is medical or recreational, used by the therapist or by the patient, marijuana has the potential of impacting the physical therapy profession. It’s important for regulatory boards to understand the chemical effects of marijuana, as well as some of the current laws.
There are two natural compounds found in the plants of the Cannabis genus: Cannabidiol (CBD) and Tetrahydrocannabinol (THC). CBD can be extracted from hemp or from marijuana. Hemp plants are cannabis plants that contain less than 0.3 percent THC. CBD can have no more than 3 percent THC to be legal at the federal level. CBD is available in gels, gummies, oils, supplements, extracts, etc.
Marijuana plants are cannabis plants that contain higher concentrations of THC—the average strain contains 12 percent THC. THC is the main psychoactive compound in marijuana that gives the high and it is consumed by smoking and in oils, edibles, tinctures, capsules, etc.
Physical therapists may be asked by patients about the medicinal use of these CBD and THC in its various forms. Depending on the jurisdiction, some patients may be prescribed these drugs. Therefore, it is important regulators understand how these substances affect the body. We have two receptors, the CB1 receptor and the CB2 receptor. THC binds to both the CB1 and CB2 receptors to exert its various pharmacotherapeutic effects, but CBD has little binding affinity for either of them.
The CB1 receptor is primarily found in the central nervous system. It relates to movement, pain modulation, balance, and coordination. By agonist effects on the CB1 receptor, marijuana alters the user’s perceptions and mood and disturbs memory function and learning and leads to impaired judgment.
The CB2 receptors are primarily found in the peripheral tissues that seem to be linked to the immune system. This connects to some aspects of the acute pain-spasm-pain-spasm response. Both receptors are presynaptic receptors, so they moderate the neurotransmitter release.
Unlike opioids, CBD doesn’t bind with the same receptors and therefore doesn’t interfere with the breathing function. The problem with opioids is that if you take too much, you simply stop breathing. Additionally, it takes a lot to reach the lethal dose of marijuana. A lethal dose is equivalent to smoking 20,0000 to 40,000 marijuana cigarettes.
The absorption of the drug depends on delivery. Inhaling marijuana has a quick, rapid onset. Oral or transcutaneous deliveries are slower and less predictable. There are too many factors with individual digestion for edibles to have a consistent effect. For people who are using it for acute pain, smoking can be better as it delivers relief in about twenty-two minutes. Additionally, patients can sometimes eat a very small amount of an edible and have strong adverse reactions. Inhalation allows for better moderation of the amount and effects of the drug.
As mentioned previously, CBD has little binding affinity for either of the two cannabinoid receptors (CB1 and CB2). In fact, CBD can interfere with the binding of THC and dampen the psychoactive effects. CBD modulates several non-cannabinoid receptors and ion channels and various receptor-independent pathways:
Recreational marijuana first became legal in 2012 in Colorado and Washington. As of 2016, twenty-eight states have some form of legalized recreational or medical marijuana programs.
As Oregon’s Transportation Safety Division Administrator and Governor’s Highway Safety Representative, Troy Costales often needs to examine testing for drivers with commercial drivers licenses.
Most of the time, these tests are done through urine. Unfortunately, urine tests cannot tell the difference between THC and CBD. The test simply shows the presence of a substance. However, as we just discussed, CBD doesn’t usually cause impairment. Either way, the test is going to come back positive. When a definitive answer is needed if THC or CBD is present, blood tests can differentiate between the two. Therefore, in major cases, such as someone with a commercial drivers license, a blood test is preferred. While blood tests can differentiate between CBD and THC, unless the CBD oil is created in a lab, it will still have a percentage, albeit low, of THC. Additionally, since the FDA doesn’t regulate CBD, it could be advertised as being THC-free when in actuality the product is not THC-free.
There was a situation in Oregon where a school bus driver was taking CBD oil for aches and pains by applying it to their knee. The individual completed a random drug test and had a positive finding. When you have a positive drug test and a commercial drivers license, you're done; you have lost the commercial drivers license everywhere in the country and your career is over. However, very few individuals understand these potential ramifications of the use of these unregulated over-the-counter CBD remedies.
Physical Therapists are sometimes approached by sellers of CBD products claiming to reduce pain. Representatives market the CBD products to other licensees such as chiropractors, massage therapists, and other health care practitioners. Can you sell them at a physical therapy clinic too?
In short, it’s not a good idea. At this time, it is advisable for physical therapists to stay away from suggesting CBD products to a patient as there can be multiple problems. In addition to the fact that the FDA doesn’t monitor CBD, CBD could diminish pain so significantly that the individual can no longer reliably self-report activities which cause difficulty or may be injuring themselves further without pain as a natural deterrent. Even more concerning, is that CBD can also negatively affect their coordination, which could negatively impact their therapy or lead to issues such as falls.
Regulating the use of alcohol among licensees is fairly straight forward. Alcohol has a reliable, reproducible curve for when impairment occurs. It’s fairly easy to recognize the presence of alcohol and create guidelines for impairment; we all know that an inebriated physical therapist working on patients endangers those patients. However, marijuana is not so straightforward. How much marijuana causes impairment—and testing what that amount is—is tricky. It’s going to be difficult to say what amount causes impairment because it’s based on multiple factors: your genetic makeup, the amount of years you’ve used it, etc. It is possible to have a high level of THC yet no impairment. Conversely, someone else could have a low level of THC and very high impairment. It's not easy to extrapolate across populations. It’s almost as if each person is their own control. Completely unlike alcohol with norms that can be applied throughout the population, a reaction to THC is very individual and may even vary from episode to episode.
Therefore, as a board, rely on your processes, rely on things that you've used in the past, but at the same time, know that this is not alcohol. The ability to tie presence with impairment doesn't work. There's going to have to be two things in your case deliberations: prove presence, then also prove impairment. Presence does not always mean impairment in the case of marijuana.
Regulation of marijuana is still in its infancy. It’s important for regulatory boards to keep up with the latest science, emerging trends, and changes in laws and policies.
Public Member, Oregon Board of Physical Therapy
Mr. Costales is a public member of the Oregon Board of Physical Therapy and the inaugural Chair of the PT Compact Commission. He has been the state of Oregon’s Transportation Safety Division Administrator and Governor’s Highway Safety Representative since September of 1997. During his time as the Governor’s Representative he has worked for three different Governors. Troy has over thirty years of experience in Transportation Safety, including twenty as the Administrator of the Division. He is a member of the executive management team for the Oregon Department of Transportation.
M. Suzanne Tinsley, PT, PhD, NCS
Assistant Dean for Development, LSU Health – Shreveport
Dr. Tinsley, PhD, PT, NCS, received her Master’s in Physical Therapy from Texas Woman’s University in 1986 and her PhD in Neuropharmacology from Louisiana State University Health Sciences Center–Shreveport in 1999. Dr. Tinsley has been on faculty at LSU Health-Shreveport for thirty years. She is an Assistant Dean in the School of Allied Health Professions at LSU Health – Shreveport and holds joint appointments of Associate Professor in the Department of Rehabilitation Sciences and the Department of Neurology. In February 2017, she was named the first Richard C. Parks Endowed Professor in Neurological Rehabilitation by LSU Health. Dr. Tinsley teaches medical pharmacology and Neuroscience in the School of Allied Health Professions. She is a Board Certified Neurologic Physical Therapist and recently served as Interim Program Director of the Neurologic Physical Therapy Residency Program at LSU Health-Shreveport Rehabilitation Faculty Clinic. Dr. Tinsley is also the Assistant Director Neurologic Rehabilitation in the new LSU Health Shreveport Center for Brain Health. She has presented both internationally and nationally as well as numerous continuing education seminars on the topics of pharmacology and neurologic rehabilitation. In addition, she has served on the ABPTS Academy of Content Experts. Dr. Tinsley has published in the area of pharmacology and rehabilitation and is an author of a pharmacology textbook for McGraw-Hill Publishing.
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