A Healthesystems publication

Spring 2014

Medical Marijuana: A Primer For Workers’ Compensation

As more states move to legalize marijuana for medical or recreational use, the potential clinical risks for patients and financial implications for workers’ compensation payers will need to be considered carefully.

Is Marijuana Safe For Use in Workers’ Compensation?

Marijuana (Cannabis sativa) contains over 400 chemical components. Marijuana contains a mix of diverse chemical compounds called cannabinoids that also includes delta-9-tetrahydrocannabinol (THC), the most psychoactive component of marijuana and the one thought to cause the feeling of being “high” that users experience.

Marijuana is classified as a Schedule I substance under the Controlled Substances Act. Other Schedule I substances include heroin, methylenedioxymethamphetamine (commonly called ecstasy) and lysergic acid diethylamide (commonly called LSD). These drugs have a high potential for abuse, lack accepted medical uses, and are not accepted as safe for use under medical supervision.1

Study Results are Inconclusive

Studies that examined the benefits and harm posed by marijuana use produced conflicting results. Some found in favor of marijuana use for medicinal purposes but were small-scale, conducted on animals, or lacked the statistical power needed to make a solid conclusion. Other studies showed a possible synergistic effect between the cannabinoid and opioid systems.2,3,4 These studies suggested the potential for lower opioid doses, fewer side effects, and delayed tolerance, but were not large-scale in nature or were not conducted on humans so their conclusions cannot be relied upon regarding benefits to humans.

No large-scale randomized controlled human trials have been conducted that sufficiently ease concerns about the inherent risks of marijuana use. This is a factor in failed efforts to legalize marijuana for medical use on a federal level. The FDA requires all drugs seeking approval to undergo rigorous controlled trials to prove both safety and efficacy. Approval of marijuana at the state level bypassed this important safety process.

The answers to the questions below and other questions included in the FDA approval process are important. Without them, physicians are left to employ a trial and error approach.

We do know that the effects of smoked and ingested marijuana are not equal. The chemical processes that occur in the body change with the route of administration. We also know that the techniques used to smoke marijuana can lead to dosage inconsistencies. The depth of inhalation and time before exhalation can cause significant variations in the amount of the drug received. The side effects, duration of action, associated “high” and potential drug interactions also vary. More study is needed.

Unanswered questions

Marijuana also lacks the standardization required in the FDA-approval process. Important questions are left unanswered such as:

  • How should marijuana be dosed?
  • Is there a dose-response effect?
  • How much marijuana is toxic or will cause a harmful effect?
  • What is the chemical purity or acceptable batch variations?
  • What are the best and worst routes of administration?
  • What are the side effects?
  • What are potential contraindications for use and/or potential drug-interactions?

Varied Risks

The potential for increased utilization of marijuana should raise concerns about possible adverse risks with payers. Marijuana use can cause the following:

  • delay an injured worker’s return to work9
  • elevate risks for lung cancer when smoked10
  • induce psychosis and other mental health disorders11
  • lead to addiction or diversion12,13,14
  • contribute to motor vehicle accidents15

Expectations for Workers’ Compensation

The FDA has not approved any uses for marijuana. Neither the American College of Occupational and Environmental Medicine (ACOEM)5 nor Official Disability Guidelines (ODG) recommends its use. Furthermore, it is illegal under federal law for a physician to prescribe marijuana or for anyone to sell or use it. A growing number of states have legalized the sale and use of marijuana within the state. Technically, federal law supersedes state law; however, the federal government has informally indicated it will not interfere in those states.

Approved indications for medical use vary by states in which it is legal. Some have open-ended indications that allow determination on a case-by-case basis. Others use vague language to describe approved uses and leave considerable room for interpretation. For example, California law states that medical marijuana is approved for “chronic or persistent medical conditions that substantially limit a person’s ability to conduct one or more major life activities as defined in the Americans with Disabilities Act of 1990, or if not alleviated, may cause serious harm to the person’s safety, physical or mental health.”6 This could be interpreted to include severe, chronic or debilitating pain; muscle spasms/spasticity; seizures; post traumatic stress disorder (PTSD); migraines; arthritis; and other conditions commonly seen in workers’ compensation populations. In Colorado, 94 percent of the 108,000 registered medical users in 2012 qualified based on a diagnosis of severe pain.7

It is not likely that medical marijuana will replace mainstay therapies in the near future. There is however, the potential for it to be recommended as an alternative therapy in cases where other approved therapies failed, or as adjunctive therapy.

Concerns have also been expressed about adverse drug-disease interactions and the dangerous cumulative adverse effects that can occur when marijuana is used concomitantly with therapies commonly prescribed in workers’ compensation — opioid analgesics, sedative-hypnotics and muscle relaxants.8 Interactions with other drugs can alter the effects of marijuana as well as the duration and intensity of the effects.

Recommendations for Payers

Healthesystems recommends against approving claims for medical marijuana in light of the absence of FDA-approved uses. Future legislative changes could require approval in some states under some circumstances. Payers would be prudent to work with their pharmacy benefit manager (PBM) to proactively develop a marijuana strategy and establish policies and procedures for handling any future marijuana claims. Documentation of medical necessity, step therapy, signed agreements, urine drug screening and the like could be incorporated. Educational materials and guidance for claims professionals on how best to handle such claims should be part of the effort.



1 -Controlled Substance Schedules. U.S. Department of Justice Drug Enforcement Administration. Office of Diversion Control Web site. http://www.deadiversion.usdoj.gov/schedules/#define. Accessed March 20, 2014.
2 -Welch SP. Interaction of the cannabinoid and opioid systems in the modulation of nociception. International Review of Psychiatry. 2009;21(2):143-151.
3 -Cichewicz DL, McCarthy EA. Antinociceptive synergy between Δ9-tetrahydrocannabinol and opioids after oral administration. The Journal of Pharmacology and Experimental Therapeutics. 2003;(304):1010-1015.
4 -Abrams DI, Couey P, Shade SB, et al. Cannabinoid-opioid interaction in chronic pain. Clinical Pharmacology and Therapeutics. 2011;90(6)844-851.
5 -Brown D. A look at marijuana and workers’ compensation. Sedgwick Connection web site. February 7, 2014. http://blog.sedgwick.com/2014/02/07/a-look-at-marijuana-and-workers-compensation/. Accessed March 20, 2014.
6 -Medical Marijuana Program Frequently Asked Questions. California Department of Public Health web site. http://www.cdph.ca.gov/programs/MMP/Pages/MMPFAQ.aspx. Accessed March 20, 2014.
7 -Burke J. Drug Diversion and Abuse: Marijuana revisited. Pharmacy Times. http://www.pharmacytimes.com/publications/issue/2013/December2013/Drug-Diversion-and-Abuse-Medical-Marijuana-Revisited. December 2013. Accessed February 20, 2014.
8 -Harrison S. Workers compensation industry braces for impact of medical marijuana. Employers urged to set policies on marijuana. Business Insurance Web site. http://www.businessinsurance.com/article/20131215/NEWS08/312159977/workers-compensation-industry-braces-for-impact-of-medical-marijuana?tags=%7C79%7C92%7C329%7C304. December 15, 2013. Accessed March 20, 2014.
9 -Callaghan RC, Allebeck P, Sidorchuk A. Marijuana use and risk of lung cancer: a 40-year cohort study. Cancer Causes Control. 2013:24:1811-1820.
10 -Marijuana. Science-based information for the public. University of Washington Alcohol & Drug Abuse Institute (ADAI) Web site. http://adai.washington.edu/marijuana/factsheets/medications.pdf. June 2011. Accessed February 24, 2014.
11 -Marijuana Abuse. Is Marijuana Addictive? National Institute on Drug Abuse Web site. http://www.drugabuse.gov/publications/marijuana-abuse/marijuana-addictive. July 2012. Accessed February 24, 2014.
12 -Price M. Marijuana addiction a growing risk as society grows more tolerant. American Psychological Association Web site. http://www.apa.org/monitor/2011/05/marijuana.aspx. May 2011. Accessed February 24, 2014.
13 -Drug Facts. Is Marijuana Medicine? National Institute on Drug Abuse Web site. http://www.drugabuse.gov/publications/drugfacts/marijuana. Accessed February 24, 2014.
14 -Burke J. Drug Diversion and Abuse: Marijuana revisited. Pharmacy Times. http://www.pharmacytimes.com/publications/issue/2013/December2013/Drug-Diversion-and-Abuse-Medical-Marijuana-Revisited. December 2013. Accessed February 20, 2014.
15 -Clinical Pharmacology [database online]. Tampa, FL: Gold Standard Inc; 2014. http://www.goldstandard.com/. Accessed March 20, 2014.
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