In some embodiments, the invention provides a non-addictive analgesic co-formulation comprising an opioid agonist in an amount sufficient to confer analgesia in a mammalian subject (such as a human) and a neutral opioid antagonist in an amount sufficient to inhibit peripheral effects of the opioid agonist, and insufficient to block substantial central effects of the opioid agonist in the subject. The formulation may be formulated for oral administration to the subject. Such formulations, and methods of using the same, may also deter diversion, inhibit peripheral effects of the opioid agonist, and reduce addiction liability.