The drug combination morphine/naltrexone (trade name Embeda) is an opioid combination pain medication developed by King Pharmaceuticals for use in moderate to severe pain. The active ingredients are morphine sulfate and naltrexone hydrochloride; morphine being an opioid receptor agonist and naltrexone an opioid receptor antagonist. It is a schedule 2 controlled substance, and is intended for long-term pain caused by malignancy or where lower tiers of the pain management ladder have already been exhausted, and where medications such as oxycodone would otherwise have been indicated.