28Sep/090
POPSCI.COM: DARPA-funded nanotech drug automatically regulates morphine dose to injured soliders on the battlefield
The drug relies upon nanotech particles that carry both morphine and its antagonist, known as Naloxone. That creates a self-regulating feedback system where Naxolone only activates to suppress morphine when blood oxygen levels drop too low. The antagonist then goes inactive when oxygen blood levels return to normal, and allows more morphine to become available.