Research on application of opioids to skin wounds is very sparse and has primarily been performed in palliative care patients. These reports demonstrate that topical opioid gel (morphine or diamorphine) provided rapid and effective relief. In some patients pain subsided within 20 minutes after application with a long-lasting (7-8 hours) effect. Fundamental aspects regarding topical application of opioids onto skin wounds are still lacking. For example, issues such as optimal dose and dose-effect relationships have not been investigated. We hope to determine these in this study.