Controlled-release compositions containing opioid agonist and antagonist

A transdermal delivery system for an opioid analgesic, comprising an opioid agonist and an opioid antagonist contained in a reservoir or matrix and capable of supplying from the system in a controlled manner so that, when the system is applied to the skin of a human patient, the opioid agonist and the opioid antagonist are released at substantially proportionate rates, the opioid agonist is delivered at a rate effective mean relative release to provide analgesia to the patient for at least 3 days, and opioid antagonist is delivered at a mean relative release rate sufficient to reduce a side effect associated with the opioid agonist, said antagonist selected from the group consisting of naloxone, naltrexone, cyclazocine, levallorphan, and pharmaceutically acceptable salts thereof.