Update on abuse-resistant and abuse-deterrent approaches to opioid formulations.

The number of opioid analgesic prescriptions has increased since 1990. Opioids are being prescribed for longer periods of time for both cancer- and noncancer-associated moderate to severe chronic pain. Concurrent with the increased prescribing of opioids has been an increase in their diversion from prescribed use and their abuse; frequently, this abuse occurs after the opioid analgesic has been physically or chemically manipulated to increase the concentration or bioavailability of the active ingredient. Formulations of opioids have been designed to resist the extraction of the active opioid from prescribed products through the incorporation of physical barriers or to deter the reinforcing effects of opioids through the incorporation of antagonists or other ingredients that only become active when the analgesic is used improperly. However, none of these formulations are currently commercially available in the United States. This paper describes the formulations now under development and their potential clinical utility and impact on society. These emerging opioid formulations designed to reduce the risk of misuse and/or abuse may be useful to physicians in meeting the important goals of maximizing pain relief and minimizing prescription opioid abuse.