Medical Marijuana in the Workplace: Challenges and Management Options for Occupational Physicians.

Although possession and use of marijuana is prohibited by federal law, legalization in four states (Alaska, Colorado, Oregon, and Washington) and allowance for palliation and therapy in 19 others may reposition the drug away from the fringes of society. This evolving legal environment, and growing scientific evidence of its effectiveness for select health conditions, requires assessment of the safety and appropriateness of marijuana within the American workforce. Although studies have suggested that marijuana may be used with reasonable safety in some controlled environments, there are potential consequences to its use that necessitate employer scrutiny and concern. Several drug characteristics must be considered, including Δ-tetrahydrocannabinol (Δ-THC, or THC) concentration, route of administration, dose and frequency, and pharmacokinetics, as well as the risks inherent to particular workplace environments.