Duragesic an Durogesic (IPA: [ˌdɚə'dʒiʒɪk]) are the trade names of fentanyl transdermal therapeutic systems, and are used for moderate to severe pain relief. Since Duragesic/Durogesic release fentanyl, a potent opioid, slowly through the skin, one patch may provide 72 hours of pain relief. Though its initial onset after a patch has been applied is roughly (under normal conditions) 8-12 hours, thus Duragesic patches are often prescribed with another opioid (such as morphine sulfate) to handle breakthrough-pain.