Opioid use disorders have significantly increased over the past two decades, affecting between 26 and 36 million people worldwide. There are several unique methodological challenges in the design and conduct of studies assessing the efficacy of various opioid use disorder treatments. Nonetheless, with careful planning these can all be effectively managed. Barry J. Dussault, Jr. and Henry J. Riordan of World Wide Clinical Trials explains that given the currently available treatment options and increasing global prevalence more clinical trials of drugs to treat opioid use disorders with eventual subsequent approvals of new and improved treatments for this growing epidemic are essential.