Historical Perspective on Medical Marijuana
The use of marijuana dates back to 2737 BCE when the Chinese Emperor Shen Nung described its therapeutic uses for joint pain, constipation, malaria, and childbirth. Around 1000 BCE its therapeutic and religious use achieved great popularity in India. Medicinal use of marijuana continued, and spread to Africa, the Middle East, and the Arabian Peninsula into the 18th century. Marijuana was introduced into western medicine by physician W.B. O’Shaughnessy, who in 1839, described its’ use for pain control, muscle relaxation, appetite stimulation, and as a treatment for nausea and seizures. Use of marijuana declined in the U.S. from 1900 through the 1930’s due to difficulty standardizing preparations, development of alternative “mainstream” pharmaceuticals, and taxation by the Federal Marijuana Tax Act of 1937. In 1942 marijuana was removed from the U.S. Pharmacopoeia and then in 1970, it was classified as a “Schedule 1” drug, falling into the same category as heroin under The Controlled Substances Act.
Indications for Medical Use
It is important to note that marijuana is not a first line drug of choice for any medical condition. Instead, it is typically recommended when available therapies have been ineffective, or when side-effects of those therapies have been unacceptable. Marijuana may act synergistically with opioids to enhance the inability to feel pain and to allow lower doses of opioids.
Appropriate indications for medical marijuana have been published by organizations such as the National Academy of Sciences, Health Canada, the State of New York, and the Office of Medicinal Cannabis (OMC) in the Netherlands. Indications for medical marijuana include the following:
- Poor appetite, weight loss, and wasting in cancer or HIV/AIDs
- Autoimmune disorders such as rheumatoid arthritis, inflammatory bowel disease, and lupus erythematosis
- Pain from HIV/AIDS or cancer
- Chronic neuropathic pain from multiple causes including diabetes, nerve trauma, post-shingles, complex regional pain syndrome (CRPS), etc.
- Nausea and vomiting from chemotherapy, radiation, or other medications
- Neuropsychiatric conditions including epilepsy, Parkinson’s disease, Tourette’s syndrome, and PTSD
- Intractable glaucoma
- Pain and spasticity from multiple sclerosis or spinal cord injury
Federal versus State Laws
Marijuana remains illegal at the Federal level. At the state level, as of January, 2017, 28 states and the District of Columbia have legalized medical marijuana. In addition, eight states and the District of Columbia have legalized marijuana for recreational use. The FDA has approved several synthetic marijuana preparations, such as Dronabinol and Nabilone.
Medical marijuana cannot be allowed by any employer who is governed by federal or state regulations that specifically prohibit its use (e.g. FMCSA, NRC). Employer prohibition of marijuana use by employees (medical or recreational) is still supported by federal law and does not violate the Americans with Disabilities Act (ADA). Levels of marijuana in the urine or saliva do not correlate with the level of impairment (unlike blood or breath alcohol levels) so there is no “safe or acceptable” level.
Should Employers Consider Allowing Employees to Use Medical Marijuana?
Employers will likely face increasing pressure from employees to allow medical marijuana use for non-federally regulated jobs. Ongoing legal challenges to workplace drug testing policies may force changes to employer drug testing protocols. Consideration for medical marijuana use by workers must address critical considerations such as:
- Safety sensitive vs. non-safety sensitive jobs
- Underlying diagnoses
- Frequency of use and route of administration (inhalation vs. ingestion)
- Duration of use (short-term vs. long-term)
- Necessary work accommodations or restrictions
- Worker would have to notify the employer of any changes to dose, frequency, or route of administration
- In most cases, medical marijuana should not be administered while the employee is at work
- Pre-placement evaluations including consultation with an Occupational Health physician and neuro-cognitive testing should be available as needed
The Risk of Impairment and Impact on Safety
Marijuana use has a negative effect on learning, memory, attention, reasoning, and concentration. The duration and magnitude of action varies with the route of administration. Inhaled marijuana peaks in 15 to 30 minutes, and effects taper in 2-3 hours. Ingested marijuana peaks in 2-3 hours, and effects taper in 4-12 hours. Marijuana is metabolized predominantly in the liver and is excreted into the bile and urine. In a flight simulator study, pilots were impaired after marijuana use at 1, 4, and even 24 hours after consumption.
Marijuana use (acutely) is associated with an increased risk of motor vehicle collisions and especially fatal crashes. Marijuana use while driving can result in delayed braking reaction time, impaired lane tracking, and inattention to speed. A meta-analysis conducted by Rogeberg and Elvik which consisted of 21 studies in 13 countries with 239,739 participants found that marijuana use (self-reported or found in blood, urine, or saliva tests) was associated with a 20% to 30% greater risk of a motor vehicle crash. In addition, a study posted by the National Institute on Drug Abuse found that postal workers who tested positive for marijuana on a pre-placement drug test had 55% more industrial accidents and their absentee rate was 75% higher.
In contrast, some studies have shown no association between marijuana use and workplace safety. In 1994, a survey of 9,097 employees aged 18 and older showed that there was no association between marijuana use (recent or remote) and the risk of work-related accidents.Also, in 2014, another study found that worker who tested positive for marijuana use were not more likely to have had a work-related injury than the control group, according to the results posted in the Journal of Addictive Diseases. Studies also suggest that tolerance to the effects of marijuana develop in long-term users, and that impairment for short-term users is significantly greater by comparison.
Medical marijuana has been in use throughout the centuries. Although marijuana is not a first line therapy for any medical condition, it does have proven efficacy for a number of difficult-to-treat chronic medical illnesses. Medical marijuana has both benefits and risks. The increasing use of medical marijuana by employees will pose a threat with regard to workplace safety, and will create challenges for current drug testing program policies. Should a company decide to allow the use of medical marijuana for employees, strict safeguards will need to be implemented to address safety sensitive work, any necessary job accommodations or restrictions, or ongoing fitness-for-duty issues. The bottom line is that medical marijuana is neither a miracle drug nor a safety nightmare.
About the author:
Our presenter for this webinar is Dr. Fred Kohanna, Vice-President of Occupational Health and Chief Medical Officer for AllOne Health based in Wilmington, Massachusetts. He began his career as an emergency medicine physician and has now worked for over 20 years in the field of occupational and environmental medicine for which he is board certified. Dr. Kohanna develops innovative, customized occupational and environmental health services solutions for a range of clients. His expertise includes environmental exposures, medical surveillance programs, drug and alcohol testing, work-related injury management, wellness and health promotion, travel medicine, and pre-placement health screening. Dr. Kohanna received his undergraduate degree from Columbia University and his medical degree from George Washington University. He has an MBA from Northeastern University. He is a Fellow in the American College of Occupational and Environmental Medicine, and is a certified Medical Review Officer and DOT medical examiner.