Michele Paige of Enlyte, writing for WorkersCompensation.com, tackles the issues surrounding topical medications:

Topical analgesics—medications applied directly to the skin—are commonly used to manage pain in workers’ compensation claims involving injuries like sprains, strains or muscle aches. While these medications offer targeted relief and are often seen as safer alternatives to opioids, they also present rising cost concerns...

Topical analgesics have become a significant cost driver in pharmacy spend for workers' compensation. According to the Workers Compensation Research Institute (WCRI), these products now account for approximately 22% of total medication
payments. Dermatological agents and NSAIDs continue to be top cost drivers, and both the number of injured employees using topical medications and the associated costs have been increasing.

You can read the full article here.  The WCRI study that she references is "Topical Analgesic Use in Workers’ Compensation" (2021).  You can find more information, including details on how to get a copy, on the study's page of our website.