This invention relates to a tamper-resistant transdermal dosage form comprising an active agent, such as an opioid, or a pharmaceutically acceptable salt thereof, a free base of an adverse agent, such as an opioid antagonist, and a pharmaceutically acceptable salt of an adverse agent, such as an opioid antagonist. The transdermal dosage form allows an effective amount of the active agent, or a pharmaceutically acceptable salt thereof, to be transdermally administered to an animal. The invention further relates to methods for treating or preventing pain in an animal comprising contacting the skin of an animal in need thereof with the transdermal dosage form of the invention for an amount of time sufficient to treat or prevent pain.
