As use and misuse of prescription drugs in the U.S. increases, employers are becoming increasingly concerned over the possible effects of such use on worker safety. Cautions issued by manufacturers of commonly prescribed drugs such as Xanax, Oxycodone and Lortab recommend that the user not operate machinery or engage in potentially dangerous tasks. Despite these restrictions, growing numbers of Americans routinely take these drugs to manage long-term medical conditions.

Last week, in Bates v. Dura Automotive Systems, Inc., the Sixth Circuit Court of Appeals issued a decision in a lawsuit brought by former employees of an automobile parts manufacturer that was experiencing an increase in workplace accidents. As part of its efforts to address this issue, Dura adopted a policy strictly prohibiting employees who use these pain and anxiety medications from working in safety sensitive jobs. The plaintiffs had legal prescriptions for these drugs, and were fired after they refused to stop using the prescriptions. All had doctors' notes indicating that their use of these substances did not present a risk of harm to themselves or others.

The plaintiffs sued under the Americans with Disabilities Act, claiming that the policy discriminates against employees with disabling medical conditions by screening them out without an individual analysis of their ability to perform the job. The Sixth Circuit dismissed the claim, holding that the plaintiffs in this case were not disabled as defined under the ADA. However, this suit predated the ADA Amendments Act of 2008. Under that law's broadened definition of disability, the plaintiffs in this case very likely would have been considered disabled or regarded as disabled.

This decision does not give employers dealing with employee prescription drug use much comfort. First, employers' drug policies should clearly state that employees must disclose in advance any legal prescription drug use that could adversely affect their ability to safely perform the job. Next, employers should treat employees' use of pain or anxiety medication on a case-by-case basis. Neither the drugs' generic warnings nor the employees' physicians' opinions should be the sole basis for a decision on whether the employee can safely perform the job while using these medications. Under the ADA, the employer is entitled to an independent medical review of the interaction between the particular employee's use of prescription drugs, and the possible safety impact on the workplace.

As prescription drug use increases, employers will need clear policies in order to balance legitimate safety concerns with employee rights.