Analytical true positive workplace drug testing results can occur due to legitimate use of prescription medication or OTC (over-the-counter) medication. Given the increasing incidence of prescription drug misuse and abuse in the United States over the past two decades, the likelihood of encountering positive workplace drug test results has grown. Amphetamine positive results due to prescription medication were discussed in Chap. 12. Although benzodiazepines are not included on the SAMHSA drug testing panel, prescription use of these drugs commonly yields positive test results. Similarly, topical cocaine preparations can lead to positive cocaine test results. Additionally, various prescription pain medications containing opiates may produce positive opiate test results. Marinol, a synthetic form of marijuana, which is metabolized in the same way as marijuana, can cause positive marijuana results in workplace drug testing.