A new era in painkillers has officially started, as FDA approved King Pharmaceuticals' extended-release morphine drug Embeda.

This is a story that has been several months in the making, and the public health potential is huge. When extended-release morphine originally came out, they were desperately needed for chronic pain patients (like those with cancer). The problem with such drugs, like OxyContin (oxycodone), is that they were easily abused. Several drug companies have been working on tamper-resistant XR pain drugs, and now the first has crossed the finish line.

King's Embeda has an interesting formulation - the outer shell is XR morphine, an opioid receptor agonist, which works to relieve pain quickly and potently. The key is the inner core of the pill - the core is made of naltrexone, which is an opioid receptor antagonist. (Docs have used this to treat morphine addiction, and to counter effects of morphine.)

If Embeda is taken as prescribed, the naltrexone core passes through the body without any effect, and no one is the wiser. However, if someone tries to tamper with the drug to get a high - crushed, chewed, dissolved in alcohol - the naltrexone is released to counter any effects of the morphine.

Now, they're still a bit iffy on how well it deters people - King says "the clinical significance of the degree of this reduction has not been established, and there is no evidence that the naltrexone in Embeda reduces the abuse liability." But the unmet need is there, and the potential is there.

Embeda was approved for the management of moderate to severe pain when a continuous,
around-the-clock opioid analgesic is needed for an extended period of time. Here is King's press release. Bloomberg reports that King is also working on tamper-resistant Remoxy, an long-acting oral oxycodone that could compete with OxyContin, and Acurox, a short-acting oxycodone that guards against overdose.