Many prescription drugs, including but not limited to: opioids, amphetamines, benzodiazepines, and similar prescriptions, are considered to be legal in drug testing situations granted the employee has a verifiable prescription. These drugs can cause cognitive impairment, addiction, and other ill health effects. In addition, these prescriptions are more easily abused due to the rate at which the compound leaves one's body.
However, medical marijuana is not considered a prescription in the workplace, even if an employee holds a prescription, verifiable by the state. Cannabis is used to treat the same symptoms as the drugs listed above and more. Cannabis has shown to cause cognitive impairment, but is not physically addictive nor does it produce ill health effects.
Reform employee testing.