The drug combination morphine/naltrexone (trade name Embeda) was an opioid combination pain medication developed by King Pharmaceuticals for use in moderate to severe pain. The active ingredients were 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 was 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.
Embeda capsules are formulated with morphine pellets and an inner core containing naltrexone. The purpose of this formulation was to prevent people from crushing the tablet for intravenous injection or intranasal ingestion. If crushed, the naltrexone would mix with the morphine and competitively antagonizes morphine's physiological effects. Ingested orally and intact, the inner core encapsulating the naltrexone is not digestible in the gastrointestinal tract.
However, King Pharmaceuticals voluntarily recalled Embeda in 2011 after complaints from the FDA in regards to King Pharmaceuticals omitting information regarding the potentially fatal reaction if crushed and swallowed and also for making unsubstantiated claims regarding Embeda's reduced abuse potential.